Contactless conductivity sensors

Abstract

A system, device, or apparatus for measuring conductivity of a fluid. A system may include a flow cell, a sensor assembly, and a controller. The sensor assembly includes a first sensor and a second sensor. The controller is configured to modulate an amplitude of a stimulus signal output to the first sensor to tune a resolution and a measurement range of the fluid. The controller is also configured to condition a received signal obtained from the second sensor to tune a starting point of measurement. The conductivity of the fluid is determined based on the stimulus signal and the conditioned received signal, the received signal corresponding to the stimulus signal modulated by the conductivity of the fluid. The first sensor induces an electric current signal in the fluid based on the stimulus signal. The second sensor measures the electric current signal in the fluid and outputs the received signal.

Description

Attorney Docket No. 218079-023501 (IDF00019 PCT)CONTACTLESS CONDUCTIVITY SENSORSCROSS REFERENCE

[0001] This application claims the benefit and priority to U.S. Provisional Application No. 63 / 714,397, filed on October 31 , 2024, and titled “CONTACTLESS CONDUCTIVITY SENSORS”, the entire content of which is incorporated by reference herein.FIELD

[0002] The present disclosure relates to the field of dialysis systems. More particularly, to contactless sensors for measuring ionic conductivity of fluids in, for example, peritoneal and hemodialysis systems.BACKGROUND

[0003] Monitoring ionic conductivity of fluids has widespread applications such as, for example, in the medical field and in the production of fuels, oils, and foodstuffs. In the medical field, for example, peritoneal dialysis fluid (“PDF”) can be utilized to treat renal diseases including renal failure. The PDF can be introduced into the peritoneal cavity of a patient’s body, where the PDF absorbs waste products produced by the body. After a suitable period of time, the PDF can be drained from the patient’s body to remove the waste products. To ensure the PDF is suitable for treating the patient, the parameters of the PDF can be measured.SUMMARY

[0004] In some embodiments, a probe for measuring a conductivity of a conductive fluid includes a flow cell; a sensor assembly including a first sensor and a second sensor; and a controller. In some embodiments, the controller is configured to modulate an amplitude of a stimulus signal output to the first sensor to tune a resolution and a measurement range of the conductive fluid. In some embodiments, the controller is configured to condition a received signal obtained from the second sensor to tune a starting point of measurement. In some embodiments, the conductivity of the conductive fluid is determined based on the stimulus signal and the conditioned received signal. In someAttorney Docket No. 218079-023501 (IDF00019 PCT) embodiments, the received signal corresponds to the stimulus signal modulated by the conductivity of the conductive fluid.

[0005] In some embodiments, the first sensor induces an electric current signal in the conductive fluid in the flow cell based on the stimulus signal. In some embodiments, the second sensor measures the electric current signal in the conductive fluid and outputs the received signal.

[0006] In some embodiments, the stimulus signal includes a sine wave signal.

[0007] In some embodiments, the probe includes a transmitting front-end. In some embodiments, the transmitting front-end enables tuning the resolution and the measurement range of the conductive fluid by the sensor assembly.

[0008] In some embodiments, the transmitting front-end includes a first filter. In some embodiments, the first filter, based on an input signal, outputs a reference DC signal. In some embodiments, the transmitting front-end includes a modulator. In some embodiments, the modulator obtains the input signal and the reference DC signal as input and outputs a square wave signal modulated in amplitude based on a duty cycle of the input signal and the reference DC signal. In some embodiments, the transmitting front-end includes a second filter. In some embodiments, the second filter converts the square wave signal to a sine wave signal. In some embodiments, the transmitting front-end includes a driver. In some embodiments, the driver energizes the first sensor using the sine wave signal.

[0009] In some embodiments, the second filter includes an amplifier. In some embodiments, the amplifier is embedded into the second filter. In some embodiments, the amplifier is separate from the second filter and connected in series so that the signal passes first through the second filter and second through the amplifier.

[0010] In some embodiments, increasing the amplitude of the stimulus signal increases the resolution and decreases the measurement range by the sensor assembly. In some embodiments, decreasing the amplitude of the stimulus signal increases the measurement range and decreases the resolution by the sensor assembly.

[0011] In some embodiments, the probe includes a receiving front-end. In some embodiments, the receiving front-end enables tuning the starting point of the measurement range based on programmable offsets.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0012] In some embodiments, increasing the programmable offsets increases the starting point of the measurement range by the sensor assembly. In some embodiments, decreasing the programmable offsets decreases the starting point of the measurement range by the sensor assembly.

[0013] In some embodiments, the programmable offsets do not modify a total length of the measurement range.

[0014] In some embodiments, the receiving front-end includes a derivator. In some embodiments, the derivator obtains the received signal from the second sensor. In some embodiments, the receiving front-end includes a positive front-end. In some embodiments, the positive front-end, based on a first programmable offset, conditions a positive differentiated signal. In some embodiments, the receiving front-end includes a negative front-end. In some embodiments, the negative front-end, based on a second programmable offset, conditions a negative differentiated signal. In some embodiments, the receiving front-end includes an analog-to-digital (AD) converter. In some embodiments, the AD converter receives the positive differentiated signal and the negative differentiated signal and outputs a digital signal corresponding to the conditioned received signal.

[0015] In some embodiments, the flow cell includes an inlet, an outlet, and one or more conduits. In some embodiments, the inlet is in fluid communication with the outlet through the one or more conduits to enable the conductive fluid to be directed through the flow cell.

[0016] In some embodiments, the one or more conduits includes a first conduit, and a second conduit.

[0017] In some embodiments, the first sensor and the second sensor are located at the first conduit.

[0018] In some embodiments, the first sensor is located at one of the first conduit and the second conduit and the second sensor is located at the other of the first conduit and the second conduit not including the first sensor.

[0019] In some embodiments, a method for measuring a conductivity of a fluid in a flow cell using a probe includes modulating, by a controller, an amplitude of a stimulus signal; energizing, by the controller, a first sensor based on the stimulus signal. In some embodiments, the method includes obtaining, by the controller, a received signal from a second sensor based on the stimulus signal,Attorney Docket No. 218079-023501 (IDF00019 PCT) the received signal corresponding to the stimulus signal modulated by the conductivity of the fluid. In some embodiments, the method includes determining, by the controller, the conductivity of the fluid based on the stimulus signal and the received signal.

[0020] In some embodiments, the method includes generating, in response to the stimulus signal, a first electromagnetic (EM) field at the first sensor and inducing an electric current signal in the fluid. In some embodiments, the method includes sensing, by the second sensor, a second EM field based on the electric current signal in the fluid. In some embodiments, the method includes generating the received signal at the second sensor. In some embodiments, the received signal is induced at the second sensor by the electric current signal in the fluid.

[0021] In some embodiments, modulating the amplitude of the stimulus signal includes obtaining a first pulse width modulation (PWM) signal and a second PWM signal, determining a reference DC signal based on the first PWM signal, determining a square wave signal based on the second PWM signal and the reference DC signal, and filtering the square wave signal to output the stimulus signal, the stimulus signal including a sine wave signal. In some embodiments, increasing the amplitude of the stimulus signal decreases a measurement range and increases a resolution of the measurement, and decreasing the amplitude of the stimulus signal increases the measurement range and decreases a resolution of the measurement.

[0022] In some embodiments, the second filter includes an amplifier. In some embodiments, the amplifier is embedded into the second filter. In some embodiments, the amplifier is separate from the second filter and connected in series so that the signal passes first through the second filter and second through the amplifier.

[0023] In some embodiments, the method includes conditioning, by the controller, the received signal from the second sensor.

[0024] In some embodiments, conditioning the received signal from the second sensor includes determining, at a positive front end, a positive differential signal based on the received signal, determining, at a negative front end, a negative differential signal based on the received signal, amplifying, based on a first programmable offset, the positive differential signal, amplifying, based on aAttorney Docket No. 218079-023501 (IDF00019 PCT) second programmable offset, the negative differential signal, and converting the amplified positive differential signal and the amplified negative differential signal into a digital signal. In some embodiments, the conditioned received signal received by the controller is the digital signal.

[0025] In some embodiments, the conditioning uses a positive and negative peak detection function. In some embodiments, the conditioning uses a positive and negative edge rectification function.

[0026] In some embodiments, increasing an electrical offset increases a starting conductivity of a measurement range, and decreasing the electrical offset decreases the starting conductivity of the measurement range.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Some embodiments of the disclosure are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the embodiments shown are by way of example and for purposes of illustrative discussion of embodiments of the disclosure. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the disclosure may be practiced.

[0028] FIG. 1 is a schematic diagram illustrating a system, according to some embodiments.

[0029] FIG. 2 is a schematic diagram illustrating the system, according to some embodiments.

[0030] FIG. 3 is a schematic illustration of the system in FIG. 1 , according to some embodiments.

[0031] FIG. 4A is a block diagram of a non-limiting example of a transmitting front end, according to some embodiments.

[0032] FIG. 4B is a block diagram of a non-limiting example of a transmitting front end, according to some embodiments.

[0033] FIG. 4C is a block diagram of a non-limiting example of a transmitting front end, according to some embodiments.

[0034] FIG. 5 is a block diagram of another non-limiting example of the transmitting front end, according to some embodiments.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0035] FIG. 6 is a block diagram of another example transmitting front end, according to some embodiments.

[0036] FIG. 7 is a block diagram of a non-limiting example of a receiving front end, according to some embodiments.

[0037] FIG. 8 is a block diagram of another non-limiting example of the receiving front end, according to some embodiments.

[0038] FIG. 9 is a flow diagram of a method, according to some embodiments.

[0039] FIG. 10 is a flow diagram of a method, according to some embodiments.

[0040] FIG. 11 is a flow diagram of a method, according to some embodiments.

[0041] FIG. 12 is a flow diagram of a method, according to some embodiments.

[0042] FIG. 13 is a flow diagram of a method, according to some embodiments.Attorney Docket No. 218079-023501 (IDF00019 PCT)DETAILED DESCRIPTION

[0043] Various embodiments of the present disclosure relate to systems, devices, and apparatuses for contactless measurement of an ionic conductivity of a fluid located in a hydraulic circuit. Contactless can, in some embodiments, refer to electrodes that are outside of the fluid channel or vessel. The system can be contactless to avoid electrode fouling, which occurs when a layer of unwanted substances accumulates on an electrode’s surface. In some embodiments, contactless can mean not in direct physical contact with a fluid. The hydraulic circuit may include one or more conduits through which the fluid flows therethrough, the ionic conductivity of the fluid being measured at one or more of the conduits. The fluid being measured can be utilized for different applications including, but not limited to, a peritoneal dialysis fluid (“PDF”) utilized in the treatment of renal diseases. The ionic conductivity of the fluid can be measured using a sensor assembly. The ionic conductivity of the fluid is indicative of a dissolved ion content in the fluid. In some embodiments, the systems, devices, and apparatuses may be utilized in a hemodialysis system.

[0044] According to some embodiments, the hydraulic circuit may include a flow cell. The flow cell may include an inlet, an outlet, and a conduit extending between the inlet and the outlet. In some embodiments, the flow cell may include one or more conduits. In some embodiments, the flow cell may include a first conduit and a second conduit extending between the inlet and the outlet. The first conduit and the second conduit may thereby define a closed loop flow path for an electric current signal to be directed through the flow cell for measuring the ionic conductivity of the fluid therein.

[0045] According to some embodiments, the sensor assembly may include a pair of sensors arranged on or near the hydraulic circuit so as to enable measuring the ionic conductivity of the fluid therein while maintaining fluidic isolation between the fluid and the sensor assembly components. The sensor assembly may include a transmitting sensor and a receiving sensor. In some embodiments, the transmitting sensor and the receiving sensor may be coil sensors. In some embodiments, the transmitting sensor and the receiving sensor may be toroidal coil sensors. In some embodiments, the transmitting sensor and the receiving sensor may each include a single coil, the transmitting sensor and the receiving sensor being configured to include a respective turns ratio based on anAttorney Docket No. 218079-023501 (IDF00019 PCT) application of the sensor assembly. In some embodiments, the transmitting sensor may be referred to as a transmitting coil, transmitting sensor coil, transmitter, transmitter coil, and the like. In some embodiments, the receiving sensor may be referred to as a receiving coil, receiving sensor coil, receiver, receiver coil, receiver sensor, and the like.

[0046] By utilizing electromotive force, the transmitting sensor is configured to generate an electromagnetic (“EM”) field based on a stimulus signal. The transmitting sensor may apply the EM field to the fluid in the hydraulic circuit. Based on the ion concentration of the fluid, the EM field from the transmitting sensor induces a varying electric current signal in the fluid. The electric current signal may be directed through the electric signal path determined by the hydraulic circuit and the fluid therein from the transmitting sensor to the receiving sensor.

[0047] The receiving sensor is exposed to the EM field generated by the electric current signal in the fluid. The changing magnetic flux of the electric current signal in the fluid generates an electric current signal in the receiving sensor that is proportional to the electric current measured in the fluid. The electric current signal in the fluid thereby promotes an electrical waveform at the receiving coil corresponding to a receiving signal.

[0048] The stimulus signal and the receiving signal from the respective transmitting sensor and the receiving sensor enables determining the ionic conductivity of the fluid in the flow cell. The ionic conductivity may be determined based on the mutual inductance observed between the two sensors and via the sensed fluid. As the ion concentration in the fluid directly influences electrical conductivity, the ionic concentration of the fluid can be determined based on the stimulus signal from the transmitting sensor and the receiving signal from the receiving sensor along with the temperature of the fluid.

[0049] According to some embodiments, a controller may be utilized to determine the ionic conductivity of the fluid. The controller may be in electrical connection with the sensor assembly including the transmitting sensor and the receiving sensor to enable determining the ionic conductivity of the fluid. In some embodiments, the controller may drive the transmitting sensor to generate the stimulus signal, thereby inducing the electric current signal in the fluid. In some embodiments, the controller may also receive the receiving signal from the receiving sensor.Attorney Docket No. 218079-023501 (IDF00019 PCT)Based on the stimulus signal and the receiving signal, the controller may determine the ionic conductivity of the fluid, as will be further described herein. In some embodiments, the controller may be a micro-controller. In some embodiments, an electrical printed circuit board (“PCB”) may include the controller. In other embodiments, the sensor assembly may include the electrical PCB, the PCB including the controller.

[0050] The controller may include an integrated electronics front-end. In some embodiments, the electronics front-end of the controller may include a single- ended coil drive at one end of the transmitting sensor. The single-ended coil drive at the electronics front-end modulates an amplitude of the stimulus signal at only one end of the transmitting sensor, thereby improving efficiency of operation and ease of management by the controller while also reducing a number of components in the electronic circuitry.

[0051] According to some embodiments, the electronics front-end of the controller utilizes a sinusoidal stimulus signal rather than other signals such as, for example, a square wave signal. Utilizing sine wave signals provides improved noise reduction during measurement, provides a higher signal to noise ratio, and thereby allows for improved accuracy in measurement.

[0052] According to some embodiments, the transmitting sensor may be coupled to the receiving sensor at the electronics front-end of the controller so as to provide integrity test functionality. In this regard, the front-end circuitry enables tuning the amplitude of the stimulus signal utilizing the controller. Accordingly, the controller does not modulate the stimulus signal at the transmitting coil by utilizing feedback circuitry integrally formed with the transmitting sensor. Instead, the transmitting sensor has a single coil that is driven by the controller to produce the stimulus signal for generating the EM field and to induce the varying electric current signal in the fluid.

[0053] According to some embodiments, the measurement range of the controller may be adaptively adjusted based on the target value(s) of the fluid’s electrical properties. This enables improved sensitivity by the controller at narrow measurement ranges. This also enables variable measurement ranges by the controller depending on the selected fluid. For example, the measurement range may vary based on the formulation of the PDF. Accordingly, the controller including the sensor assembly may be adaptively utilized for differentAttorney Docket No. 218079-023501 (IDF00019 PCT) applications while ensuring that accuracy and precision requirements for detection of the ionic conductivity of the fluid according to the relevant pharmacological standards are being met.

[0054] According to some embodiments, the flow cell is configured so as to promote coupling between the sensors in the sensor assembly via the fluid flowing through a closed-loop fluidic channel of the flow cell, while simultaneously enabling contact-less in-line monitoring of the fluid. In this regard, the sensors are not in direct contact with the fluid being measured. According to some embodiments, the sensor assembly may include a transmitting sensor and a receiving sensor on separate branches of the flow cell. This facilitates reducing noise from cross-coupling between the two coils. Other types of known sensors are typically on the same conduit or on the same branch. In addition, the sensor assembly’s adaptability and biocompatibility enables its deployment across various application areas.

[0055] According to some embodiments, the flow cell may be made of one or more materials. The one or more materials of the flow cell may reduce a cost and effort associated with manufacturing the flow cell. In some embodiments, the one or more materials of the flow cell may not include borosilicate glass 3.3 due to its higher relative cost and due to the difficulty associated with manufacturing fluid conduits out of the materials. In some embodiments, the one or more materials of the flow cell can be any polymeric material that is insensitive to electromagnetic fields. In some embodiments, the one or more materials can be workable by extrusion, injection molding, or any suitable manufacturing method to form the corresponding flow cell.

[0056] Among those benefits and improvements that have been disclosed, other objects and advantages of this disclosure will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the disclosure that may be embodied in various forms. In addition, each of the examples given regarding the various embodiments of the disclosure which are intended to be illustrative, and not restrictive.

[0057] FIG. 1 is a schematic diagram illustrating a system 100, according to some embodiments.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0058] The system 100 includes a flow cell 102 and a sensor assembly 104. The flow cell 102 includes an inlet 106, an outlet 108, a conduit 110, and a conduit 112. The conduit 110 may define a first fluidic path and the conduit 1 12 may define a second fluidic path. The inlet 106 may be in fluid communication with the outlet 108 through the conduit 110 and the conduit 112, the conduit 110 and the conduit 112 defining the respective first fluidic path and the second fluidic path. A fluid 114 may be directed to flow between the inlet 106 and the outlet 108 through the conduit 110, conduit 112, or both. For example, the fluid 114 may be a peritoneal dialysis fluid (“PDF”) flowing between the inlet 106 and the outlet 108 through the conduit 110 and the conduit 112. The fluid 114 can flow into the inlet 106 and be provided to one or both of conduit 110 and conduit 112, then flow out from the outlet 108. As such, in some embodiments, the fluid in the first fluidic path and the fluid in the second fluidic path can flow in a same direction (i.e., from the inlet 106 to the outlet 108).

[0059] In the flow cell 102, the first fluidic path of the conduit 110 and second fluidic path of the conduit 112 define a fluidic path 1 16. The fluidic path 116 of the flow cell 102 enables an electric current signal applied to the fluid 114 to be directed along an electrical signal path 118 between the first fluidic path of the conduit 110 and the second fluidic path of the conduit 112. In some embodiments, the electrical signal path 118 may be in a same direction as a direction of the fluid 114 flow in the flow cell. In some embodiments, the electrical signal path 118 may be in a different direction than the direction of the fluid 114 flow in the flow cell.

[0060] The sensor assembly 104 includes a transmitting sensor 122 and a receiving sensor 124. The transmitting sensor 122 and the receiving sensor 124 may be located on one of the conduit 110 or the conduit 1 12. Referring to FIG. 1 , in some embodiments, the transmitting sensor 122 and the receiving sensor 124 may be located on the conduit 110 defining the first fluidic path. In other embodiments, although not shown in the figures, the transmitting sensor 122 and the receiving sensor 124 may be located on the conduit 112 defining the second fluidic path.

[0061] According to some embodiments, the transmitting sensor 122 and the receiving sensor 124 may be sensor coils. That is, in some embodiments, the transmitting sensor 122 and the receiving sensor 124 may each include a coil windingAttorney Docket No. 218079-023501 (IDF00019 PCT) including a respective turns ratio. In some embodiments, the transmitting sensor 122 may include a single coil winding including an inlet and an outlet connected to an electrical front end for modulating an amplitude of the stimulus signal. In some embodiments, the receiving sensor 124 may include a single coil winding including an inlet and an outlet connected to an electrical front end for conditioning the received signal.

[0062] The transmitting sensor 122 may include a turns ratio of M:1. The turn ratio of the transmitting sensor 122 directly influences the EM field generated at the transmitting sensor 122. That is, the greater the number of turns in the transmitting sensor 122, the greater the EM field induction at the transmitting sensor 122 that is applied to the fluid 114 in the flow cell 102. The receiving sensor 124 may include a turns ratio of 1 :N. The turn ratio of the receiving sensor 124 also directly influences the induced current signal at the receiving sensor 124. That is, the greater the number of turns in the receiving sensor 124, the greater the induced electrical current signal corresponding to the received signal at the receiving sensor 124. In this regard, the turns ratio of the transmitting sensor 122 and the receiving sensor 124 may be determined based on the application of the system 100 and the sensor assembly 104 therein. In some embodiments, value of M may be greater than a value of N. In other embodiments, the value of M may be less than a value of N. In yet other embodiments, the value of M may be equal to the value of N.

[0063] According to some embodiments, system 100 may include controller 130. The controller 130 may be in electrical connection with the sensor assembly 104. The controller 130 may drive the sensor assembly 104 to produce a stimulus signal and to obtain a received signal from the sensor assembly 104 in response to the stimulus signal. In some embodiments, sensor assembly 104 may include controller 130. For example, in some embodiments, the sensor assembly 104 may include an electronic printed circuit board (“PCB”), the PCB including controller 130 arranged thereon. In other embodiments, the system 100 may include the controller 130 in electrical connection with the sensor assembly 104. For example, the controller 130 may be on a different PCB than the sensor assembly 104.

[0064] According to some embodiments, the controller 130 may include a processor and a memory. The memory may be a non-transitory computer readable mediaAttorney Docket No. 218079-023501 (IDF00019 PCT) having stored thereon instructions executable by the processor to enable the controller 130 to perform operations for determining an ionic conductivity of a fluid utilizing sensor assembly 104 in accordance with the present disclosure. The controller 130 is configured to determine the ionic conductivity of the fluid 114 based on the mutual inductance observed between the two paired sensors of the sensor assembly 104 via the sensed fluid 114. As the ion content that is dissolved in the fluid 114 directly influences electrical conductivity, the ionic concentration of the fluid 114 can be determined by the controller 130 through conductivity measurements by the sensor assembly 104. In some embodiments, the controller 130 may be a micro controller.

[0065] According to some embodiments, the sensor assembly 104 includes the transmitting sensor 122 and the receiving sensor 124, and the controller 130 may be in electrical connection with the transmitting sensor 122 and the receiving sensor 124. In this regard, the controller 130 may energize the transmitting sensor 122, thereby causing the transmitting sensor 122 to produce a stimulus signal. The stimulus signal induces an electromagnetic (“EM”) field at the transmitting sensor 122, which is then applied to the fluid 1 14 in flow cell 102, the fluid 114 having a certain ionic conductivity. In response to applying the EM field induced at transmitting sensor 122 to the fluid 114 in flow cell 102, a varying electrical current signal is induced in the fluid 114. The varying electrical current signal is directed through the fluid 114 along the electrical signal path 118 in flow cell 102. That is, the electrical current signal is directed from transmitting sensor 122 to receiving sensor 124. It is to be appreciated that the electrical current signal follows along the fluidic path 116 in the flow cell 102 back to the transmitting sensor 122 to thereby define the electrical signal path 118. Although the fluid flows from the inlet 106 to the outlet 108, the electrical current signal flows in a closed loop path in the flow cell 102.

[0066] The fluid 114 in flow cell 102 acts as a conductive wire, in which the varying electrical current signal in the fluid 114 generates a varying EM field. The receiving sensor 124 senses the varying EM field caused by the varying electrical current signal in the fluid 114. In response to the EM field due to the electrical current signal in fluid 114, the receiving sensor 124 generates a received signal, which is induced by the EM field of the electrical current signal in the fluid 114. That is, the electrical current signal generated along the fluidicAttorney Docket No. 218079-023501 (IDF00019 PCT) path 116 and the electrical signal path 118 from the transmitting sensor 122 and sensed by the receiving sensor 124 promotes an electrical waveform corresponding to the received signal at the receiving sensor 124. In addition, the pairing mechanism between transmitting sensor 122 and receiving sensor 124, and through fluid 114, thereby promotes a received signal that is modulated by both the stimulus signal and the ionic conductivity of the fluid 114 in the sensor assembly 104.

[0067] Accordingly, the controller 130 may obtain the received signal from sensor assembly 104. That is, the controller 130 may obtain the stimulus signal from transmitting sensor 122 and may obtain the received signal from receiving sensor 124. Based on the stimulus signal and the received signal, the controller 130 may determine the ionic conductivity of the fluid 114 in the flow cell 102, as will be further described herein.

[0068] The controller 130 may include one or more components configured to energize the transmitting sensor 122 to cause the transmitting sensor 122 to generate the stimulus signal at the sensor assembly 104 and to receive the received signal from the receiving sensor 124 of the sensor assembly 104 in response to energizing the transmitting sensor 122. In this regard, the pairing mechanism of the transmitting sensor 122 and the receiving sensor 124 through the fluid 114 in the flow cell 102 promotes the received signal modulated by both the stimulus signal and the conductivity of the fluid 114. In this regard, based on the stimulus signal and the received signal, the controller 130 can determine the ionic conductivity of the fluid 114 in the flow cell 102. For example, the system 100 may be utilized in a hemodialysis machine for monitoring and / or setting the ionic concentration of a dialysis fluid to ensure a patient is receiving a dosage within certain parameters in accordance with the degree of pureness required by relevant pharmacopoeia standards. In another example, the system may be monitoring the ionic concentration to maintain the dialysis fluid within a ± 5% error with respect to nominal ion content.

[0069] According to some embodiments, the flow cell 102 may be made of materials that enable the sensor assembly 104 to be arranged on or near the conduit 110, 112 of the flow cell 102 and to enable the sensor assembly 104 to measure the ionic conductivity of the fluid 114 flowing through the flow cell 102. In some embodiments, the flow cell 102 may be made of one or more materials to enableAttorney Docket No. 218079-023501 (IDF00019 PCT) the EM field generated at the transmitting sensor 122 to induce a varying electric current signal in the fluid 114 flowing through the flow cell 102 and to enable the receiving sensor 124 to sense the EM field of the electric current signal in the fluid 114 to then generate the received signal. In some embodiments, the flow cell 102 may be made of one or more materials other than borosilicate glass 3.3. That is, in some embodiments, the one or more materials forming the flow cell 102, and the corresponding conduits 110, 112, may not include borosilicate glass 3.3.

[0070] FIG. 2 is a schematic diagram illustrating a system 100, according to some embodiments. The configuration of the system 100 in FIG. 2 is an alternative to the configuration of the system 100 in FIG. 1. Features described regarding FIG. 1 above will not be redescribed in further detail, unless specifically referenced otherwise.

[0071] In the embodiment of FIG. 2, transmitting sensor 122 is located on conduit 110 and receiving sensor 124 is located on conduit 112. In this regard, the transmitting sensor 122 is located on the first fluidic path of conduit 110 and the receiving sensor 124 is located on the second fluidic path of conduit 112.

[0072] The controller 130 may apply a voltage to the transmitting sensor 122 to energize the transmitting sensor 122, thereby driving the transmitting sensor 122 to generate the stimulus signal and to induce an EM field at the transmitting sensor 122. The transmitting sensor 122 may be arranged at conduit 110 so as to apply the EM field to the fluid 114 in conduit 110. The fluid 114 flowing through the flow cell 102, and defining the fluidic path 116, may have a certain ion content. In response to the transmitting sensor 122 applying the EM field to the fluid 114 in the flow cell 102, the EM field from the transmitting sensor 122 induces a varying electrical current signal in the fluid 114.

[0073] The varying electrical current signal is directed through the fluid 114 along the electrical signal path 118 in flow cell 102 from transmitting sensor 122 to receiving sensor 124, the transmitting sensor 122 being arranged at conduit 110 and the receiving sensor 124 being arranged at conduit 112. It is to be appreciated that the electrical current signal runs along the fluidic path 116 from transmitting sensor 122 to receiving sensor 124 and back to transmitting sensor 122, thereby defining the electrical signal path 118. Although the fluid flows fromAttorney Docket No. 218079-023501 (IDF00019 PCT) the inlet 106 to the outlet 108, the electrical current signal flows in a closed loop path in the flow cell 102.

[0074] The fluid 114 in flow cell 102 acts similar to a conductive wire, in which the varying electrical current signal induced in the fluid 114 generates a varying EM field due to the ions in the fluid 114. The receiving sensor 124 senses the varying EM field caused by the varying electrical current signal in the fluid 114. In response to the EM field produced by the electrical current signal in the fluid 114, the receiving sensor 124 generates a received signal. That is, by applying the EM field from the electric current signal in the fluid 114 to the receiving sensor 124, the receiving sensor 124 generates the received signal. The receiving sensor 124 senses the EM field from the electrical current signal at conduit 112, which promotes an electrical waveform corresponding to the received signal at the receiving sensor 124.

[0075] The controller 130 obtains the received signal from the receiving sensor 124 of sensor assembly 104. In addition, the controller 130 also obtains the stimulus signal from the transmitting sensor 122. The pairing mechanism between transmitting sensor 122 and receiving sensor 124 through fluid 114 promotes a received signal that is modulated by both the stimulus signal and the ionic conductivity of the fluid 114. That is, based on the stimulus signal and the received signal, the controller 130 may determine the ionic conductivity of the fluid 114 indicative of a total dissolved ion content in the fluid 114 in the flow cell 102, as will be further described herein. In some embodiments, when the transmitting sensor 122 is arranged at one of conduit 110 and conduit 112 and the receiving sensor 124 is arranged at the other of conduit 110 and conduit 112 that does not include the transmitting sensor 122 arranged thereon, determining the ionic conductivity of the fluid 114 may include the controller 130 accounting for the distance between the transmitting sensor 122 and the receiving sensor 124 along the electrical signal path 118. For example, one or more parameters at the controller 130 may be conditioned or calibrated to accommodate for the distance between the transmitting sensor 122 and the receiving sensor 124.

[0076] FIG. 3 is a schematic illustration of the system 100, according to some embodiments.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0077] The system 100 includes one or more sections for stimulating the sensor assembly 104 and for determining the ionic conductivity in the fluid 114 in flow cell 102. The one or more sections may include, but is not limited to, a power section 134, a digital section 136, an analog section 138, a sensing section 140, other sections, or any combinations thereof. In some embodiments, the system 100 may include a PCB 132, the PCB 132 including the one or more sections arranged thereon. In other embodiments, the system 100 may include a plurality of PCB 132, the one or more sections being arranged on one of the plurality of PCB 132.

[0078] The power section 134 may be configured to receive an input power 135 and output one or more voltages. The one or more voltages output by the power section 134 may be utilized to power the one or more other sections including, but not limited to, digital section 136, analog section 138, sensing section 140, other sections, one or more components therein, or any combinations thereof, to enable the stimulation of the sensor assembly 104 and determining of the ionic conductivity of the fluid 114 in the flow cell 102. For example, the PCB 132 may receive an input voltage of 12 Vdc and may supply one or more voltages to the digital section 136, analog section 138, and the sensing section 140. In some embodiments, the PCB can include various components 162 such as a re-program button, a debug button or mode, a bus 166, a serial, a shielding can, or any combination thereof.

[0079] According to some embodiments, the power section 134 may include one or more converters 142. In some embodiments, the converters 142 may include one or more DC / DC converters. For example, the input voltage may be 12 Vdc and the power section 134 may convert the 12 Vdc to 5 Vdc and to 0.5 Vdc. In other embodiments, the converters 142 may include AC / DC converters. For example, the input voltage may be 120 Vac and the power section 134 may convert the input voltage to one or more DC output voltages. In some embodiments, the power section 134 may further include a stabilization module 144. The stabilization module 144 may be configured to maintain the one or more output voltages at their respective value or values to enable performing the ionic conductivity measurements of the fluid 114. In some embodiments, the stabilization module 144 can ensure that the generated output voltages remain within desired ranges based on corresponding specifications of theAttorney Docket No. 218079-023501 (IDF00019 PCT) sensor assembly 104. In some embodiments, the stabilization module 144, by maintaining output voltages, can reduce noise that could otherwise impact sensor performance. As a result, the stabilization module 144 can improve a sensing accuracy by reducing power supply noise.

[0080] The digital section 136 may be configured to control an operation of the other sections including, but not limited to, power section 134, analog section 138, sensing section 140, other sections, or any combinations thereof. In this regard, the digital section 136 provides the logic for controlling one or more of the components in the other sections to enable driving the sensor assembly 104 to generate the stimulus signal at transmitting sensor 122 and to determine the ionic conductivity of the fluid 114 based on the received signal from the receiving sensor 124.

[0081] According to some embodiments, the digital section 136 may include a transceiver 146, controller 130, analog-to-digital (“AD”) converter 148, and a potentiometer 150. It is to be appreciated that the digital section 136 can include more than one potentiometer 150. For example, in some embodiments, the digital section 136 can include three potentiometers. It is to be appreciated that three potentiometers is an example and the actual number of potentiometers can vary beyond the stated example according to the principles of this disclosure. The AD converter 148 may also be referred to herein as ADC 148. The transceiver 146 may be in electrical communicable connection with a controller 152, the controller 152 controlling an operation of one or more sections of the PCB 132 to enable determining the ionic conductivity of the fluid 114 in the flow cell 102 using the sensor assembly 104. In some embodiments, the controller 152 can be described as a system level controller or the like.

[0082] The controller 130 may control the operation of the analog section 138 to enable the analog section 138 to drive the transmitting sensor 122 to generate the stimulus signal at the transmitting sensor 122 and obtain the received signal from the receiving sensor 124 in response to the stimulus signal.

[0083] The ADC 148 processes the received signal obtained from analog section 138 into a digital signal and sends the digital signal to the controller 130. In some embodiments, the controller 130 may also manage the ADC 148 for data digitalization so as to provide improved accuracy and resolution of the received signal obtained from the analog section 138. In addition, the controller 130 mayAttorney Docket No. 218079-023501 (IDF00019 PCT) also communicate the acquired data via digital communication protocols to one or more other components. In some embodiments, the controller 130 may communicate the acquired data from the analog section 138 to the controller 152 using the transceiver 146.

[0084] The potentiometer 150 may include one or more resistive elements which serves to scale the signal of the analog section 138. In this regard, the potentiometer 150 may enable the analog-digital converter 148 to convert the received signal from the analog section 138 according to an offset determined by the potentiometer 150.

[0085] In addition, the system 100 may include a programmable range and sensitivity to provide improved versatility in determining the ionic conductivity of the fluid 114 in the flow cell 102. That is, the measurement range and sensitivity of the system 100 may be programmed to enable determining the ionic concentration of different formulations of fluids. In this regard, the digital section 136 may be configured to control the one or more other sections including, but not limited to, the analog section 138 and the sensing section 140 to tune the amplitude of the stimulus signal at the transmitting sensor 122 and to tune the conditioning of the received signal from the receiving sensor 124 to program the measurement range and sensitivity of the system 100 depending on the application scenario, as will be further described herein.

[0086] It is to be appreciated by those having ordinary skill in the art that the digital section 136 does not include a digital to analog converter. That is, the digital section 136 does not include a digital to analog converter embedded therein and does not utilize the digital to analog converter to control the stimulation of the sensor assembly 104. Instead, the digital section 136 controls the analog section 138 to generate a digital square wave signal and filters it to obtain a voltage reference used to modulate the sinusoidal stimulation signal at the transmitting sensor 122. In some embodiments, the digital section 136 can control the analog section 138 to set electrical offsets using the potentiometer 150.

[0087] The analog section 138 may include a transmitting front end 154 and a receiving front end 156. The analog section 138 may be configured to utilize the transmitting front end 154 to energize the transmitting sensor 122 by applying an electrical current signal to an input of the transmitting sensor 122.Attorney Docket No. 218079-023501 (IDF00019 PCT)In response to the current signal at the input, the transmitting sensor 122 produces the stimulus signal, which thereby induces an EM field at the transmitting sensor 122.

[0088] According to some embodiments, the transmitting front end 154 of the analog section 138 may be configured to control an amplitude of the stimulus on the transmitting sensor 122 to tune the detected range of the ionic conductivity in the fluid 1 14 by the system 100 and the digital section 136. In some embodiments, a higher stimulus amplitude may improve a resolution and decrease a measurement range. In some embodiments, a lower stimulus amplitude increases the measurement range and reduces the resolution.

[0089] According to some embodiments, the receiving front end 156 of the analog section 138 may be configured to condition the received signal obtained from the receiving sensor 124 to enable the determination of the ionic conductivity of the fluid 114. That is, the receiving front end 156 may be utilized to tune the electrical offset to act on the starting point for the measurement range of the ionic conductivity. In some embodiments, a higher electrical offset increases the starting point in conductivity of the measurement range. In some embodiments, a lower electrical offset decreases the starting point in conductivity of the measurement range. It is to be appreciated by those having ordinary skill in the art that acting on the electrical offset does not modify the total length of the range of measurement but rather only defines the starting point of measurement. In some embodiments, if the electrical offset is not controlled correctly, the range of the measurement of the sensor assembly 104 can be impacted.

[0090] The sensing section 140 includes the sensor assembly 104, the sensor assembly 104 including the transmitting sensor 122 and the receiving sensor 124. The sensing section 140 may also include measurement module 158. According to some embodiments, the measurement module 158 enables the controller 130 to test the coupling between the transmitting sensor 122 and the receiving sensor 124. As such, the controller 130 may utilize the measurement module 158 to tune the amplitude of the stimulus signal at the transmitting sensor 122. In some embodiments, the sensing section 140 may further include a temperature sensor 160 arranged at the flow cell 102 to measure a temperature of the fluid 114. The controller 130 may utilize the temperatureAttorney Docket No. 218079-023501 (IDF00019 PCT) measurements obtained from the temperature sensor 160 to determine the ionic conductivity of the fluid 114 in the flow cell 102 and to ensure the fluid 114 is meeting the relevant pharmacopeia standards. In some embodiments, the temperature sensor 160 may be located near the inlet 106 of the flow cell 102. In other embodiments, the temperature sensor 160 may be located near the outlet 108 of the flow cell 102. In some embodiments, the temperature sensor 160 may be located outside the flow cell 102.

[0091] FIG. 4A is a block diagram of a non-limiting example of a transmitting front end 154 in system 100, according to some embodiments. FIG. 4B is a block diagram of a non-limiting example of a transmitting front end 154 in system 100, according to some embodiments. FIG. 4C is a block diagram of a non-limiting example of a transmitting front end 154 in system 100, according to some embodiments. Unless specific reference is made otherwise, FIG. 4A, FIG. 4B, and FIG. 4C will be referenced collectively.

[0092] The system 100 may include an analog section 138 including a transmitting front end 154 and a receiving front end 156. The transmitting front end 154 may be in electrically communicable connection with the digital section 136 and the sensing section 140. In some embodiments, the transmitting front end 154 may be in electrically communicable connection with the controller 130 in the digital section 136 and the transmitting sensor 122 in the sensing section 140.

[0093] As illustrated in FIG. 4A, according to some embodiments, the transmitting front end 154 includes a filter 202, a modulator 204, a filter 206, and a driver 208. As illustrated in FIG. 4B, in some embodiments the transmitting front end 154 includes the filter 202, the modulator 204, a filter 206B, and the driver 208. In some embodiments, the filter 206B can include a combination of a filter and an amplifier. As illustrated in FIG. 4B, in some embodiments, the transmitting front end 154 includes the filter 202, the modulator 204, the filter 206, an amplifier 207, and the driver 208. The filter 202 is in electrical connection with controller 130 and modulator 204. The modulator 204 is in electrical connection between controller 130 and filter 206 and is also in electrical connection with filter 202. The filter 206 is in electrical connection with modulator 204 and driver 208. When present, the filter 206B is in electrical connection with the modulator 204 and driver 208. As illustrated in FIG. 4C, the filter 206 is in electrical connection with modulator 204 and amplifier 207. Additionally, the amplifier 207 is inAttorney Docket No. 218079-023501 (IDF00019 PCT) electrical connection with the filter 206 and driver 208. The driver 208 outputs the stimulus signal to energize transmitting sensor 122.

[0094] The controller 130 provides a first pulse width modulation (PWM) signal 210 to filter 202. The first PWM signal 210 is tuned in duty cycle so as to define the stimulation signal amplitude. The filter 202 obtains the first PWM signal 210 from controller 130 and outputs a reference DC signal 212. The reference DC signal 212 is modulated in amplitude with a starting DC based on the first PWM signal 210. In some embodiments, the filter 202 may be a low pass filter. In other embodiments, the filter 202 may be a passive low pass filter. For example, the filter 202 can be a passive low pass filter at 1 kHz.

[0095] The controller 130 provides a second PWM signal 214 to modulator 204. In some embodiments, the second PWM signal 214 may have a 50% duty cycle. The modulator 204 obtains the second PWM signal 214 from controller 130 and the reference DC signal 212 from filter 202. The modulator 204 outputs an electrical voltage signal 216 based on the second PWM signal 214 and the reference DC signal 212. In some embodiments, the voltage signal 216 output by the modulator 204 may be a wave signal modulated in amplitude based on the reference DC signal 212. In some embodiments, the voltage signal 216 output by the modulator 204 may be the second PWM signal 214 modulated in amplitude based on the reference DC signal 212. In some embodiments, the voltage signal 216 output by modulator 204 may be a square wave signal.

[0096] In the embodiment of FIG. 4A, the filter 206 obtains the voltage signal 216 output by modulator 204 and outputs a sine wave signal 218. In the embodiment of FIG. 4B, the filter 206B obtains the voltage signal 216 output by modulator 204, amplifies the signal with the amplifier, and outputs a sine wave signal 218 that has been amplified. In the embodiment of FIG. 4C, the filter 206 obtains the voltage signal 216 output by modulator204 and outputs a sine wave signal to the amplifier 207, which amplifies the signal and outputs an amplified sine wave signal 218. The sine wave signal 218 being modulated in amplitude based on the reference DC signal 212. In this regard, the filter 206 includes therein one or more electrical components configured to filter the voltage signal 216 obtained from modulator 204 into the sine wave signal 218. In some embodiments, the filter 206 may be a band pass filter. The driver 208 obtains the sine wave signal 218 from filter 206 and outputs stimulus signal forAttorney Docket No. 218079-023501 (IDF00019 PCT) energizing the transmitting sensor 122. In some embodiments, the driver 208 may be a coil driver.

[0097] FIG. 5 is a block diagram of another non-limiting example of the transmitting front end 154 in system 100, according to some embodiments.

[0098] According to some embodiments, the transmitting front end 154 includes an oscillator 220 and the driver 208. The oscillator 220 is in electrical connection with controller 130 and the driver 208. The driver 208 is in electrical connection with oscillator 220 and transmitting sensor 122.

[0099] The oscillator220 obtains an input signal from controller 130 and outputs a sine wave signal 224 at stimulation frequency. In some embodiments, the oscillator 220 may be a sine wave oscillator. In other embodiments, the oscillator 220 may be a sine wave generator. The driver 208 obtains the sine wave signal 224 from the oscillator 220 and outputs the stimulus signal to transmitting sensor 122.

[0100] In some embodiments, the transmitting front end 154 may further include an amplifier 222, which is shown in the dashed lines in FIG. 5. The amplifier 222 may be in electrical connection with controller 130, oscillator 220, and the driver 208, with amplifier 222 being located between oscillator 220 and driver 208. In this regard, oscillator 220 obtains the input signal from controller 130 and outputs the sine wave signal 224 at stimulation frequency to amplifier 222. The amplifier 222 obtains the sine wave signal 224 from oscillator 220 and tunes the amplitude of the sine wave signal 224. The amplifier 222 outputs the tuned sine wave signal 226 to driver 208 to enable the driver 208 to output the stimulus signal to energize transmitting sensor 122.

[0101] FIG. 6 is a block diagram of another example transmitting front end 154, according to some embodiments.

[0102] The transmitting front end 154 includes oscillator 220 and driver 208. The oscillator 220 is in electrical communicable connection with controller 130 and driver 208. The driver 208 is in electrical communicable connection with oscillator 220 and the transmitting sensor 122.

[0103] The oscillator 220 obtains the input signal 210 from controller 130 and outputs the tuned sine wave signal 226. That is, the signal output by the oscillator 220 is a sine wave signal at the stimulation frequency with a tuned amplitude. The driver 208 obtains the tuned sine wave signal 226 from the oscillator 220 andAttorney Docket No. 218079-023501 (IDF00019 PCT) outputs the stimulus signal for driving the transmitting sensor 122. In some embodiments, the oscillator 220 may be a sine wave oscillator on a single chip. In other embodiments, the oscillator 220 may be a sine wave generator on a single chip.

[0104] FIG. 7 is a block diagram of a non-limiting example of a receiving front end 156 in system 100, according to some embodiments.

[0105] The receiving front end 156 includes a dual front-end to determine a differentiated signal from the received signal. The dual front-end of the receiving front end 156 allows for canceling noise effects. A programmable offset allows for tuning the range of acquisition of measurement.

[0106] The conditioning of the received signal from receiving sensor 124 using the programmable offsets at the dual front-end allows to change the measurement range. That is, tuning the programmable electrical offsets at the receiving front end 156 enables to set a starting point for the measurement range of the ionic conductivity of the fluid 114 being sensed in flow cell 102. In some embodiments, increasing the programmable offset increases the starting point in conductivity of the measurement range. For example, increasing the programmable offset may increase the starting point of the measurement range from 10 S / cm to 15 S / cm. In some embodiments, decreasing the programmable offset decreases the starting point in conductivity of the measurement range. For example, decreasing the programmable offset may decrease the starting point of the measurement range from 9.5 S / cm to 5.5 S / cm. In another example, decreasing the programmable offset may decrease the starting point of the measurement range from 9.5 S / cm to 1 .5 S / cm.

[0107] In addition, by the receiving front end 156 including programmable offsets, the controller 130 may be able to compensate for different factors including, but not limited to, calibration, manufacturing differences, size of the flow cell 102, other factors, or any combinations thereof. For example, the programmable offsets may compensate for an initial calibration of the system 100. In another example, the programmable offsets may compensate for the materials used to form the flow cell 102 conduits.

[0108] Accordingly, the amplitude modulation of the stimulus signal at the transmitting front end 154 and the adjustable offsets on the receiving front end 156 allow the sensor assembly 104 to change the measurement ranges, sensitivities, andAttorney Docket No. 218079-023501 (IDF00019 PCT) accuracies depending on the application. For example, the range of measurement may be changed based on the treatment being performed with the fluid 114. In another example, the range of measurement may be changed based on the ionic concentration of the fluid 114. In addition, the amplitude modulation of the stimulus signal at the transmitting front end 154 and the adjustable offsets on the receiving front end 156 enable the system 100 to maintain high accuracy and resolution at different working ranges of measurement.

[0109] The receiving front end 156 provides differential signal conditioning of the received signal from receiving sensor 124. In addition, the receiving front end 156 process the received signal using a single-ended signal conditioning. In this regard, the receiving front end 156 provides rejection of common-mode noise, higher dynamic range, and improved accuracy in measurement. In turn, this translates to improved performance in terms of both measurement range and sensitivity.

[0110] According to some embodiments, the receiving front end 156 includes a derivator 228, a positive front-end 230, a negative front-end 232, and a differential analog-digital converter (“ADC”) 234. The derivator 228 is located between and in electrical connection with receiving sensor 124 and each of the positive front-end 230 and negative front-end 232. The ADC 234 is located between and in electrical connection with the positive front-end 230 and negative front-end 232 and with controller 130.

[0111] The derivator 228 obtains the received signal from receiving sensor 124. The derivator 228 enables the received signal to be applied to the positive front-end 230 and the negative front-end 232 to provide the programmable offset. The programmable offset is applied at the receiving front end 156 along the two differential conditioning branches of the dual front-end. That is, the programmable offset is applied at the positive front-end 230 and the negative front-end 232. The programmable offset for the positive front-end 230 is a first programmable offset and the negative front-end 232 is a second programmable offset. In some embodiments, the first programmable offset and the second programmable offset are different.

[0112] Depending on the conductivity of the fluid 114 being sensed by receiving sensor 124, this implementation allows to adapt the dynamic range coming from theAttorney Docket No. 218079-023501 (IDF00019 PCT) respective amplifier outputs to the inputs of the ADC 234, thereby retaining high performance in terms of both measurement range and sensitivity. The ADC 234 obtains the analog signal output from the respective positive front-end 230 and negative front-end 232 and outputs a digital signal corresponding to the conditioned received signal with programmed offsets to controller 130 to enable the determining of the ionic conductivity of the sensed fluid 114.

[0113] The positive front-end 230 includes a rectifier 236, filter 238, and an amplifier 240. The rectifier 236 is located between derivator 228 and filter 238, the filter 238 is located between rectifier 236 and amplifier 240, and the amplifier 240 is located between filter 238 and ADC 234.

[0114] The rectifier 236 converts the received signal to a DC signal. In some embodiments, the rectifier 236 converts the AC signal corresponding to the received signal to a DC signal. In some embodiments, the rectifier 236 may be a positive peaks rectifier that converts the received signal to a positive DC signal.

[0115] The filter 238 obtains the positive DC signal from rectifier 236 and may remove unwanted frequency components (e g., noise) from the positive DC signal. In some embodiments, the filter 238 may also enhance certain wanted frequency components in the positive DC signal.

[0116] The amplifier 240 obtains the output from filter 238 and amplifies the DC signal output. In the positive front-end 230, the amplifier 240 allows for canceling noise effects. In some embodiments, a first programmable offset allows for tuning the range of acquisition. In some embodiments, the filter 238 may allow for canceling noise effects while the first programmable offset can allow for tuning the range of acquisition. In other embodiments, the rectifier 236 may allow for canceling noise effects. In some embodiments, the first programmable offset may allow for tuning the range of acquisition.

[0117] The negative front-end 232 includes a rectifier 242, filter 244, and an amplifier 246. The rectifier 242 converts the received signal to a DC signal. In some embodiments, the rectifier 242 converts the AC signal corresponding to the received signal to a DC signal. In some embodiments, the rectifier 242 may be a negative peaks rectifier that converts the received signal to a negative DC signal.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0118] The filter 244 obtains the negative DC signal from rectifier 242 and may remove unwanted frequency components (e.g., noise) from the negative DC signal. In some embodiments, the filter 238 may also enhance certain wanted frequency components in the negative DC signal.

[0119] The amplifier 246 obtains the output from filter 244 and amplifies the DC signal output. Referring to FIG. 7, in the negative front-end 232, the amplifier 246 may include a second programmable offset to tune the range of acquisition. In some embodiments, the filter 244 may include a second programmable offset to tune the range of acquisition. In other embodiments, the rectifier 242 may include a second programmable offset to tune the range of acquisition.

[0120] Accordingly, the offsets at the positive front-end 230 and the negative front-end 232 may be programmed depending on the application to allow the system 100 to change the range of measurement of the sensed fluid 114 using the sensor assembly 104.

[0121] According to some embodiments, instead of including derivator 228, the receiving front end 156 may include a current amplifier 248 located between and in electrically communicable connection with the receiving sensor 124 and each of the positive front-end 230 and negative front-end 232. In this regard, the current amplifier 248 may receive the received signal from the receiving sensor 124 and output an amplified received current signal to the positive frontend 230 and negative front-end 232 for conditioning.

[0122] FIG. 8 is a block diagram of another non-limiting example of the receiving front end 156, according to some embodiments.

[0123] The receiving front end 156 may include current amplifier 248, differential rectifier 250, differential filter 252, differential amplifier 254, and differential ADC 256. The current amplifier 248 may be located in between receiving sensor 124 and the differential rectifier 250. The differential rectifier 250 may be located in between current amplifier 248 and differential filter 252. The differential filter 252 may be located in between differential rectifier 250 and differential amplifier 254. The differential amplifier 254 may be located in between differential filter 252 and differential ADC 256. The differential ADC 256 may be located in between differential amplifier 254 and controller 130.

[0124] The current amplifier 248 may receive the received signal from receiving sensor 124 and output an amplified received signal to the differential rectifier 250. InAttorney Docket No. 218079-023501 (IDF00019 PCT) some embodiments, the current amplifier 248 may output a differentiated received signal. In some embodiments, the differentiated received signal output by current amplifier 248 may be an amplified differentiated received signal.

[0125] The differential rectifier 250 obtains the AC signal corresponding to the amplified received signal output by current amplifier 248 and converts the AC signal to a differentiated DC signal. That is, the differential rectifier 250 may differentiate the AC signal from the current amplifier 248 to a positive DC and negative DC signal. In some embodiments, the signal obtained from current amplifier 248 may be a differentiated signal.

[0126] The differential filter 252 obtains the differentiated DC signals from differential rectifier 250 and may remove unwanted frequency components (e.g., noise) from the differentiated DC signals. In some embodiments, the differential filter 252 may remove unwanted frequency components from the positive DC signal and the negative DC signal. The differential filter 252 may also enhance certain wanted frequency components in the DC signals. In some embodiments, the differential filter 252 may also enhance certain wanted frequency components in the positive DC signal and the negative DC signal.

[0127] The differential amplifier 254 amplifies the differentiated DC signal output by the differential filter 252. Referring to FIG. 8, the differential amplifier 254 includes the programmable offsets for the differentiated DC signal. In some embodiments, the differential amplifier 254 includes the first programmable offset for the positive DC signal and the second programmable offset for the negative DC signal. In some embodiments, the differential filter 252 may include the programmable offsets. In other embodiments, the differential rectifier 250 may include the programmable offsets.

[0128] The differential ADC 256 obtains the amplified signal from the differential amplifier 254 and converts the analog signal to a digital signal. The differential ADC 256 outputs the digital signals to the controller 130. In some embodiments, the differential ADC 256 obtains the differentiated DC signal from differential amplifier 254 and converts the differentiated DC signal to a digital signal. In some embodiments, the differential ADC 256 obtains the positive DC signal and the negative DC signal from differential amplifier 254 and converts the positive DC signal and the negative DC signal to respective digital signal and provides them to the controller 130.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0129] In some embodiments, the differential rectifier 250 may be located on its own single chip, the differential filter 252 may be on located on its own single chip, and the differential amplifier254 may be located on its own single chip. In other embodiments, the differential rectifier 250, differential filter 252, and the differential amplifier 254 may be located on a single chip.

[0130] FIG. 9 is a flow diagram of a method 300, according to some embodiments.

[0131] The method 300, or one or more portions thereof, may be performed using system 100 or one or more components thereof. The method 300 may be for measuring a conductivity of a fluid in a flow cell using a probe. The probe may include a sensor assembly and a controller. The sensor assembly may include a first sensor and a second sensor. In FIG. 1 , the sensor assembly is sensor assembly 104, the first sensor is transmitting sensor 122, the second sensor is receiving sensor 124, and the controller is controller 130.

[0132] At 302, the method 300 includes modulating an amplitude of a stimulus signal. At 304, the method 300 includes energizing the first sensor based on the stimulus signal. At 306, the method 300 includes obtaining a received signal from a second sensor based on the stimulus signal. In some embodiments, the received signal corresponds to the stimulus signal modulated by the conductivity of the fluid.

[0133] At 308, the method 300 includes determining the conductivity of the fluid based on the stimulus signal and the received signal. In some embodiments, at 308, the conductivity of the fluid is determined using the stimulus signal and the received signal and uses the fluid temperature to compensate for the fluid conditions. In some embodiments, various parameters can be controlled to ensure accurate conductivity measurements. For example, a cell constant and the properties of the coils (e.g., materials and ratio of turns) can be set as they can impact the received signal. In some embodiments, various parameters can also be tuned to control the received signal including, but not limited to, an amplitude of the stimulus signal and a conductivity of the fluid being sensed.

[0134] At 310, the method 300 includes determining the ion concentration of the fluid using the conductivity of the fluid as determined at 308. In some embodiments, the controller 130 can utilize an empirically derived relationship between the conductivity of the fluid 114 and the ionic concentration to determine the ionic concentration of the fluid 114 based on the measured conductivity of the fluidAttorney Docket No. 218079-023501 (IDF00019 PCT)114. In some embodiments, the controller 130 can utilize an empirically derived relationship between the measured voltage, the temperature of the fluid 114, and conductivity of the fluid 114 to determine the ionic concentration of the fluid 114.

[0135] To derive the empirical relationship, the flow cell 102 was tested using various conditions to characterize the behavior of the flow cell 102. For example, the flow cell 102 can be tested for various environmental conditions experienced while in use, such as, but not limited to, temperature of the fluid 114, components in the fluid 114 that add viscosity but do not impact conductivity, flow rate of the fluid 1 14, ions in the fluid (g / L), or any combination thereof. In some embodiments, the fluid 114 may contain various non-conductive viscous solutions while the flow cell 102 is in use. For example, in some embodiments, the non-conductive viscous solution within the fluid 114 was varied from about 1 .5% to about 4.25% of the fluid. One non-limiting example of a non-conductive viscous solution can be specific sugar solutions. The environmental conditions can be varied and a voltage measurement by the flow cell 102 can be obtained. For example, by adjusting only the temperature and maintaining the other environmental conditions constant, the effect of the fluid’s 114 temperature can be empirically derived. In some embodiments, the temperature was varied from 20°C to about 40°C. The effect of the other environmental conditions can be analyzed similarly. In this way, an empirical relationship between the conductivity of the fluid 114, the measured voltage, the temperature of the fluid 114, the components within the fluid 114, the flow rate of the fluid 114, or any combination thereof, can be determined to, in some embodiments, aid in determining the ionic concentration of the fluid 114.

[0136] In some embodiments, as discussed above, the controller 130 can utilize an empirically derived relationship between the conductivity of the fluid 114 and the ionic concentration to determine the ionic concentration of the fluid 114 based on the measured conductivity of the fluid 114. In some embodiments, the controller 130 can utilize an empirically derived relationship between the measured voltage, the temperature of the fluid 114, and conductivity of the fluid 114 to determine the ionic concentration of the fluid 114. For example, the conductivity of the fluid 114 may be affected by the temperature of the fluid 114, which can be accounted for by applying a temperature compensation. In someAttorney Docket No. 218079-023501 (IDF00019 PCT) embodiments, the temperature compensation can be determined by the relationship between the temperature of the fluid 114 and the measured voltage of the fluid 114, as described above. In some embodiments, the empirically derived relationships between the environmental conditions can be used the creation of a model relating conductivity of the fluid 114 to the ionic concentration of the fluid 114.

[0137] According to some embodiments, blocks 302 through 304 may be performed by a controller. In some embodiments, the controller may control one or more other components including, but not limited to, a transmitting front end, a receiving front end, the sensor assembly, other components, or any combinations thereof to measure the ionic conductivity of the fluid. In FIG. 3, the transmitting front end is transmitting front end 154 and the receiving front end is receiving front end 156.

[0138] FIG. 10 is a flow diagram of a method 400, according to some embodiments. The method 400 may be an embodiment of blocks 302, 304, 306, and 308 of the method 300 in FIG. 9.

[0139] At 402, the method 400 includes generating a first electromagnetic (EM) field at the first sensor and inducing an electric current signal in the fluid. In some embodiments, the first EM field may be induced at the first sensor in response to the stimulus signal applied to the first sensor. In some embodiments, the stimulus signal may be a modulated sine wave signal that induces a varying EM field at the first sensor.

[0140] At 404, the method 400 includes sensing a second EM field based on the electric current signal in the fluid. In some embodiments, the second EM field is sensed by the second sensor.

[0141] At 406, the method 400 includes generating the received signal at the second sensor. In some embodiments, the received signal is induced at the second sensor by the electric current signal in the fluid.

[0142] FIG. 11 is a flow diagram of a method 500, according to some embodiments. The method 500 may be an embodiment of block 302 of method 300 in FIG. 9.

[0143] At 502, the method 500 includes obtaining a first pulse width modulation (PWM) signal and a second PWM signal. In some embodiments, the controller may provide the first PWM signal and the second PWM signal to the transmitting front end, and the transmitting front end may output a modulated stimulus signalAttorney Docket No. 218079-023501 (IDF00019 PCT) based on the input signals from the controller. The transmitting front end is shown as transmitting front end 154 in FIG. 3.

[0144] At 504, the method 500 includes determining a reference DC signal based on the first PWM signal. In some embodiments, the transmitting front end includes a filter that outputs the reference DC signal based on the first PWM signal. In some embodiments, the filter is a low pass filter. In other embodiments, the filter is a passive low pass filter. The filter is filter 202, the first PWM signal is first PWM signal 210, and the reference DC signal is reference DC signal 212 in FIG. 4B-C.

[0145] At 506, the method 500 includes determining a square wave signal based on the second PWM signal and the reference DC signal. In some embodiments, the transmitting front end 154 includes a modulator that outputs the square wave signal based on the second PWM signal and the reference DC signal. In FIG. 4A-C, the modulator is modulator 204, the second PWM signal is second PWM signal 214, and the square wave signal is voltage signal 216.

[0146] At 508, the method 500 includes filtering the square wave signal to output the stimulus signal. In some embodiments, the filter includes an amplifier and thus the filtering includes amplifying. In some embodiments, the filter is arranged in series with an amplifier and thus the method 500 includes filtering and amplification of the square wave signal. In some embodiments, the stimulus signal comprises a sine wave signal. In some embodiments, the transmitting front end includes a second filter for converting the square wave signal to the stimulus signal. In some embodiments, the second filter may be a band pass filter. In FIG. 4A-C, the filter is shown as filter 206. The stimulus signal is shown as sine wave signal 218.

[0147] In some embodiments, the stimulus signal may be modulated to control an amplitude of the stimulus signal. By tuning the amplitude of the stimulus signal, the detected range of the conductivity of the fluid is acted upon. In some embodiments, increasing the amplitude of the stimulus signal decreases a measurement range and increases a resolution of the measurement. In some embodiments, decreasing the amplitude of the stimulus signal increases the measurement range and decreases a resolution of the measurement.

[0148] FIG. 12 is a flow diagram of a method 600, according to some embodiments.Attorney Docket No. 218079-023501 (IDF00019 PCT)

[0149] The method 600 may be an embodiment of blocks 302, 304, 306, 308 of method 300 in FIG. 9.

[0150] At 602, the method 600 includes conditioning the received signal from the second sensor. The second sensor is shown as receiving sensor 124 in FIG. 1 . In some embodiments, a receiving front end may obtain the received signal from the second sensor and may be utilized to condition the received signal. In some embodiments, the controller may control one or more components of the receiving front end to condition the received signal. The controller then obtains the conditioned received signal to enable determining the conductivity of the fluid, the conductivity being determined based on the stimulus signal and the conditioned received signal. The receiving front end is shown as receiving front end 156 in FIG. 3.

[0151] FIG. 13 is a flow diagram of a method 700, according to some embodiments. The method 700, or one or more portions thereof, may be an embodiment of block 602 of method 600 in FIG. 12. In some embodiments, the method 700, or one or more portions thereof, may be an embodiment of blocks, 302, 304, 306, 308 of method 300 in FIG. 9.

[0152] At 702, the method 700 includes determining a positive differential signal based on the received signal. In some embodiments, the positive differential signal may be determined at a positive front end. That is, in some embodiments, the receiving front end may include a dual front-end including a positive front end. The positive front end is shown as positive front-end 230 in FIG. 7. In some embodiments, the positive front end may include a positive rectifier for determining the positive differential signal based on the received signal. The positive rectifier is shown as rectifier 236 in FIG. 7.

[0153] At 704, the method 700 includes determining a negative differential signal based on the received signal. In some embodiments, the negative differential signal may be determined at a negative front end. That is, in some embodiments, the receiving front end may include a dual front-end including a negative front end. As such, the receiving front end includes both the positive front-end and the negative front-end. The negative front end is shown as negative front-end 232 in FIG. 7. In some embodiments, the negative front end may include a negative rectifier for determining the negative differential signalAttorney Docket No. 218079-023501 (IDF00019 PCT) based on the received signal. The negative rectifier is shown as rectifier 242 in FIG. 7.

[0154] At 706, the method 700 includes amplifying the positive differential signal. In some embodiments, the positive differential signal is amplified based on a first programmable offset. In some embodiments, the positive front end includes an amplifier. The amplifier obtains the positive differential signal from the positive rectifier and amplifies the obtained signal based on the first programmable offset. In FIG. 7, the amplifier is shown as amplifier 240.

[0155] In some embodiments, the first programmable offset may be applied at the positive rectifier. In other embodiments, the first programmable offset may be applied at a filter located between the positive rectifier and the positive amplifier. In some embodiments, the first programmable offset can be applied to the positive amplifier. In FIG. 7, the filter is shown as filter 238.

[0156] At 708, the method 700 includes amplifying the negative differential signal. In some embodiments, the negative differential signal is amplified based on a second programmable offset. In some embodiments, the negative front end includes a second amplifier. The second amplifier obtains the negative differential signal from the negative rectifier and amplifies the obtained signal based on the second programmable offset. In FIG. 7, the amplifier is shown as amplifier 246.

[0157] In some embodiments, the second programmable offset may be applied at the negative rectifier. In other embodiments, the second programmable offset may be applied at a second filter located between the negative rectifier and the negative amplifier. In some embodiments, the second programmable offset can be applied to the negative amplifier. In FIG. 7, the second filter is shown as filter 244.

[0158] At 710, the method 700 includes converting the amplified positive differential signal and the amplified negative differential signal into a digital signal. In some embodiments, the conditioned received signal obtained by the controller is the digital signal. That is, the differential signal is an analog signal that is converted into a digital signal to enable the controller to obtain the digital signal corresponding to the conditioned received signal for determining the conductivity of the fluid. In some embodiments, the receiving front end may include an ADC, the ADC receiving the differential signals from the dual front-Attorney Docket No. 218079-023501 (IDF00019 PCT) end, e.g., positive front-end and negative front-end, and outputting the digital signal. In FIG. 7, the ADC is shown as ADC 234.

[0159] By conditioning the received signal obtained from the second sensor using the programmable electrical offsets, the starting of the measurement range may be tuned. In this regard, acting on the offsets does not modify the total length of the measurement range but rather only defines the starting point of measurement range. In this regard, the one or more methods described herein may be utilized for a plurality of different applications and for different conductivities. In addition, the programmable electrical offsets enables measurement of fluids having lower or higher conductivities. In some embodiments, increasing the electrical offset increases the starting conductivity of the measurement range. In some embodiments, decreasing the electrical offset decreases the starting conductivity of the measurement range. In some embodiments, if the electrical offset is not correctly controlled, the range of measurement of the sensor can be impacted.

[0160] All prior patents and publications referenced herein are incorporated by reference in their entireties.

[0161] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases “in one embodiment,” “in an embodiment,” and “in some embodiments” as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. All embodiments of the disclosure are intended to be combinable without departing from the scope or spirit of the disclosure.

[0162] As used herein, the term “based on” is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of “a,” “an,” and “the” include plural references. The meaning of “in” includes “in” and “on.”

[0163] As used herein, the term “between” does not necessarily require being disposed directly next to other elements. Generally, this term means a configuration where something is sandwiched by two or more other things. At the same time, the term “between” can describe something that is directly next to two opposing things. Accordingly, in any one or more of the embodimentsAttorney Docket No. 218079-023501 (IDF00019 PCT) disclosed herein, a particular structural component being disposed between two other structural elements can be: disposed directly between both of the two other structural elements such that the particular structural component is in direct contact with both of the two other structural elements; disposed directly next to only one of the two other structural elements such that the particular structural component is in direct contact with only one of the two other structural elements; disposed indirectly next to only one of the two other structural elements such that the particular structural component is not in direct contact with only one of the two other structural elements, and there is another element which juxtaposes the particular structural component and the one of the two other structural elements; disposed indirectly between both of the two other structural elements such that the particular structural component is not in direct contact with both of the two other structural elements, and other features can be disposed therebetween; or any combination(s) thereof.

[0164] As used herein “embedded” means that a first material is distributed throughout a second material.

Claims

Attorney Docket No. 218079-023501 (IDF00019 PCT)CLAIMSWhat is claimed is:

1. A probe for measuring a conductivity of a conductive fluid, the probe comprising: a flow cell; a sensor assembly comprising: a first sensor, and a second sensor; and a controller, wherein the controller is configured to modulate an amplitude of a stimulus signal output to the first sensor to tune a resolution and a measurement range of the conductive fluid, and wherein the controller is configured to condition a received signal obtained from the second sensor to tune a starting point of measurement; wherein the conductivity of the conductive fluid is determined based on the stimulus signal and the conditioned received signal, the received signal corresponding to the stimulus signal modulated by the conductivity of the conductive fluid.

2. The probe according to claim 1 , wherein the first sensor induces an electric current signal in the conductive fluid in the flow cell based on the stimulus signal, and wherein the second sensor measures the electric current signal in the conductive fluid and outputs the received signal.

3. The probe according to claim 1 , further comprising: a transmitting front-end, wherein the transmitting front-end enables tuning the resolution and the measurement range of the conductive fluid by the sensor assembly.

4. The probe according to claim 3, wherein the transmitting front-end comprising: a first filter,Attorney Docket No. 218079-023501 (IDF00019 PCT) wherein the first filter, based on an input signal, outputs a reference DC signal, a modulator, wherein the modulator obtains the input signal and the reference DC signal as input and outputs a square wave signal modulated in amplitude based on a duty cycle of the input signal and the reference DC signal, a second filter, wherein the second filter converts the square wave signal to a sine wave signal, and a driver, wherein the driver energizes the first sensor using the sine wave signal.

5. The probe according to claim 4, wherein the second filter includes an amplifier and the second filter is configured to amplify the square wave signal.

6. The probe according to claim 4, wherein increasing the amplitude of the stimulus signal increases the resolution and decreases the measurement range by the sensor assembly, and wherein decreasing the amplitude of the stimulus signal increases the measurement range and decreases the resolution by the sensor assembly.

7. The probe according to claim 1 , further comprising: a receiving front-end, wherein the receiving front-end enables tuning the starting point of the measurement range based on programmable offsets,8. The probe according to claim 7, wherein the receiving front-end comprising: a derivator, wherein the derivator obtains the received signal from the second sensor, a positive front-end, wherein the positive front-end, based on a first programmable offset, conditions a positive differentiated signal, a negative front-end,Attorney Docket No. 218079-023501 (IDF00019 PCT) wherein the negative front-end, based on a second programmable offset, conditions a negative differentiated signal, an analog-to-digital (AD) converter, wherein the AD converter receives the positive differentiated signal and the negative differentiated signal and outputs a digital signal corresponding to the conditioned received signal.

9. The probe according to claim 1 , wherein the flow cell comprises: an inlet, an outlet, and one or more conduits including a first conduit and a second conduit, wherein the inlet is in fluid communication with the outlet through the one or more conduits to enable the conductive fluid to be directed through the flow cell.

10. The probe according to claim 9, wherein the first sensor and the second sensor are located at the first conduit.11 . The probe according to claim 9, wherein the first sensor is located at one of the first conduit and the second conduit, and the second sensor is located at the other of the first conduit and the second conduit not including the first sensor.

12. A method for measuring a conductivity of a fluid in a flow cell using a probe, the method comprising: modulating, by a controller, an amplitude of a stimulus signal; energizing, by the controller, a first sensor based on the stimulus signal; obtaining, by the controller, a received signal from a second sensor based on the stimulus signal, the received signal corresponding to the stimulus signal modulated by the conductivity of the fluid; and determining, by the controller, the conductivity of the fluid based on the stimulus signal, the received signal, and a temperature of the fluid.

13. The method of claim 12, the method further comprising: generating, in response to the stimulus signal, a first electromagnetic (EM) field at the first sensor and inducing an electric current signal in the fluid;Attorney Docket No. 218079-023501 (IDF00019 PCT) sensing, by the second sensor, a second EM field based on the electric current signal in the fluid; and generating the received signal at the second sensor, wherein the received signal is induced at the second sensor by the electric current signal in the fluid.

14. The method of claim 13, wherein conditioning the received signal from the second sensor comprises: determining, at a positive front end, a positive differential signal based on the received signal, determining, at a negative front end, a negative differential signal based on the received signal, amplifying, based on a first programmable offset, the positive differential signal, amplifying, based on a second programmable offset, the negative differential signal, and converting the amplified positive differential signal and the amplified negative differential signal into a digital signal, wherein the conditioned received signal received by the controller is the digital signal.

15. The method of claim 12, wherein modulating the amplitude of the stimulus signal comprises: obtaining a first pulse width modulation (PWM) signal and a second PWM signal, determining a reference DC signal based on the first PWM signal, determining a square wave signal based on the second PWM signal and the reference DC signal, and filtering the square wave signal to output the stimulus signal, the stimulus signal comprising a sine wave signal, wherein the filtering includes amplifying the square wave signal, wherein increasing the amplitude of the stimulus signal decreases a measurement range and increases a resolution of the measurement, and decreasing the amplitude of the stimulus signal increases the measurement range and decreases a resolution of the measurement.

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