Constant-current-source high-precision multi-channel temperature control system

Abstract

The utility model relates to a constant current source high-precision multi-channel temperature control system, which comprises a microprocessor, a reference voltage source and a front-end acquisition unit, the front-end acquisition unit comprises a plurality of temperature probes, a multiplexing switch, a signal amplifier, a constant current source module and a filtering connector, and each temperature probe is connected with each signal input end of the multiplexing switch through the corresponding connector; a serial communication interface of the multiplexing switch is connected with a signal input end of the microprocessor through the signal amplifier, and the constant current source module is connected with another serial port of the multiplexing switch. The constant-current-source high-precision multi-channel temperature control system can realize multi-channel temperature real-time monitoring, and at the same time, a high-precision temperature probe is utilized to cooperate with high-precision constant-current-source input and differential amplification to form an acquisition front end, so that subsequent accurate and stable 16-bit AD sampling is ensured, and the accuracy and stability of temperature monitoring data are greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of medical equipment products, in particular to a constant current source high-precision multi-channel temperature control system applied to a reaction disk of a full-automatic biochemical analyzer. Background Art

[0002] In the fully automatic biochemical analyzer, the temperature control system is used to monitor and adjust the temperature inside the reaction plate to make it fluctuate within 37℃±0.1℃. For the large reaction plate area of ​​the high-speed biochemical analyzer, considering the temperature uniformity of the reaction plate, it is very necessary to monitor multiple temperatures at the same time. At the same time, the temperature measurement accuracy has an important impact on the incubation of the reaction plate. The more accurate the temperature, the smaller the fluctuation of the enzyme reactants, so it directly affects the accuracy and repeatability of the data results.

[0003] The existing temperature control system used in fully automatic biochemical analyzers generally uses NTC thermistors to collect the temperature of the reaction disk, which directly enters the AD for collection through resistance voltage division. NTC itself has limited accuracy, and the resistance values ​​of different NTCs vary greatly. When used for multi-channel sampling of the reaction disk, the temperature data varies greatly; in addition, the resistance voltage division method is easily affected by the power supply and other factors, which directly or indirectly affects the accuracy and stability of the instrument results. Utility Model Content

[0004] The technical problem to be solved by the utility model is: to overcome the adverse effects of the NTC thermistor used in the reaction disk of the fully automatic biochemical analyzer as a multi-channel acquisition front end on the accuracy and stability of the monitoring data, and to provide a constant current source high-precision multi-channel temperature control system, which can realize real-time monitoring of multiple temperatures to obtain the temperature values ​​of multiple points on the reagent disk body, and at the same time utilize a high-precision temperature probe, cooperate with a high-precision constant current source input, and differential amplification to form an acquisition front end, to ensure subsequent accurate and stable 16-bit AD sampling, thereby greatly improving the accuracy and stability of the temperature monitoring data.

[0005] The constant current source high-precision multi-channel temperature control system includes a microprocessor, a reference voltage source for powering the microprocessor, and a front-end acquisition unit for collecting temperature signals and sending the signals to the microprocessor, wherein the front-end acquisition unit is connected to the signal input end of the microprocessor, and the reference voltage source is connected to the power input of the microprocessor; wherein the front-end acquisition unit includes a plurality of temperature probes, a multiplexing switch, a signal amplifier, a constant current source module, and a filter connector corresponding to each temperature probe, each of the temperature probes is connected to each signal input end of the multiplexing switch through a corresponding connector, the serial communication interface of the multiplexing switch is connected to the signal input end of the microprocessor via a signal amplifier, and the constant current source module is connected to another serial port of the multiplexing switch.

[0006] Specifically, the temperature probe adopts a PT1000 temperature sensor.

[0007] Specifically, the multiplexing switch adopts the MAX4052AESE multiplexing switch.

[0008] Specifically, the signal amplifier uses the INA118U high-precision instrument-grade differential amplifier chip.

[0009] Specifically, the constant current source module adopts the REF200 high-precision constant current source chip.

[0010] Specifically, the filter connector adopts a B03B-PASK-1 connector.

[0011] Specifically, the microprocessor adopts the STM32F373CBT6 processing chip.

[0012] The utility model discloses a constant current source high-precision multi-channel temperature control system, which overcomes the adverse effect of the NTC thermistor used in the reaction disk of the fully automatic biochemical analyzer as the multi-channel acquisition front end on the accuracy and stability of the monitoring data. It can realize real-time monitoring of multi-channel temperatures to obtain the temperature values ​​of multiple points on the reagent disk body, and at the same time utilizes a high-precision temperature probe, cooperates with a high-precision constant current source input, and differential amplification to form an acquisition front end, ensuring subsequent accurate and stable 16-bit AD sampling, thereby greatly improving the accuracy and stability of the temperature monitoring data. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following is a further description of a constant current source high-precision multi-channel temperature control system of the utility model in conjunction with the accompanying drawings:

[0014] Figure 1 This is the logic structure and connection principle wireframe diagram of this constant current source high-precision multi-channel temperature control system;

[0015] Figure 2 It is the circuit diagram of the filter connector in the front-end acquisition unit of the constant current source high-precision multi-channel temperature control system;

[0016] Figure 3 It is the circuit diagram of the multiplexing switch, signal amplifier, and constant current source module in the front-end acquisition unit of the constant current source high-precision multi-channel temperature control system;

[0017] Figure 4 It is a circuit diagram of the microprocessor of the constant current source high-precision multi-channel temperature control system.

[0018] In the figure:

[0019] 1- microprocessor, 2- reference voltage source, 3- front-end acquisition unit;

[0020] 31-temperature probe, 32-multiplexing switch, 33-signal amplifier, 34-constant current source module, 35-filter connector. DETAILED DESCRIPTION

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the description of the present invention, it should be understood that the terms "left", "right", "front", "back", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0023] The technical solution of the utility model is further described below with specific embodiments, but the protection scope of the utility model is not limited to the following embodiments.

[0024] Implementation method 1: Figure 1 As shown, the constant current source high-precision multi-channel temperature control system includes a microprocessor 1, a reference voltage source 2 for powering the microprocessor 1, and a front-end acquisition unit 3 for collecting temperature signals and sending the signals to the microprocessor 1, wherein the front-end acquisition unit 3 is connected to the signal input end of the microprocessor 1, and the reference voltage source 2 is connected to the power input of the microprocessor 1; wherein the front-end acquisition unit 3 includes a plurality of temperature probes 31, a multiplexing switch 32, a signal amplifier 33, a constant current source module 34, and a filter connector 35 corresponding to each of the temperature probes 31, each of the temperature probes 31 is connected to each signal input end of the multiplexing switch 32 through a corresponding connector 35, the serial communication interface of the multiplexing switch 32 is connected to the signal input end of the microprocessor 1 via the signal amplifier 33, and the constant current source module 34 is connected to another serial port of the multiplexing switch 32.

[0025] Implementation method 2: Figure 2 , 3As shown, the temperature probe 31 of this constant current source high-precision multi-channel temperature control system adopts a PT1000 temperature sensor. The PT1000 temperature sensor can achieve high-precision temperature acquisition. The multiplexer switch 32 adopts the MAX4052AESE multiplexer switch. Using the multiplexer switch MAX4052AESE as the selection device for the temperature sampling channel, up to 4 channels of high-precision temperature acquisition can be supported; the current output value of the multiplexer switch MAX4052AESE is a constant 100UA±0.5%, and the error precision is extremely low, which greatly improves the accuracy, and its temperature drift rate is only ±25ppm / ℃, which is extremely small due to the natural environment temperature fluctuation, and also greatly improves the detection accuracy. The signal amplifier 33 adopts the INA118U high-precision instrument-grade differential amplifier chip. The voltage value VO output by the INA118U high-precision instrument-grade differential amplifier chip enters the MCU from the terminal AD_T for AD sampling; the NA118U high-precision instrument-grade differential amplifier chip has an extremely low offset voltage of up to 50uV and an extremely low temperature drift of 0.5uV / ℃, which greatly improves the accuracy of the data. The constant current source module 34 uses the REF200 high-precision constant current source chip. The REF200 constant current source chip provides a precise 200uA current input current for the PT1000 platinum resistor. The I1L pin of REF200 is connected to the COMA export interface of the MAX4052AESE multiplexing switch, and I2L connects R40, R41 to AGND. The constant current source chip REF200 provides 200uA of current from the I1L and I2L channels. The filter connector 35 uses a B03B-PASK-1 connector. C66-C93 on the B03B-PASK-1 connector are filter capacitors, which process the source signal during transmission to improve the signal quality. The remaining structures and components are as described in Implementation 1 and will not be described again.

[0026] Implementation method 3: Figure 4 As shown, the constant current source high-precision multi-channel temperature control system: the microprocessor 1 adopts the STM32F373CBT6 processing chip. It has a built-in 16-bit AD acquisition, which greatly improves the detection resolution and detection accuracy compared with the conventional MCU with a built-in 12-bit AD. The remaining structures and components are as described in Implementation 1 and will not be described again.

[0027] During operation: the PT1000 temperature sensor is connected to each filter connector through interfaces J7 to J10 respectively, and after filtering by filter capacitors C66 to C93 on the B03B-PASK-1 connector to improve the quality of the signal source, the output terminals T1 to T4 of the B03B-PASK-1 connector are respectively connected and output signals to the corresponding group signal input terminals NO0A, NO0B ​​to NO3A, NO3B of the multiplexer switch MAX4052AESE chip, and the constant current source chip REF200 uses I1L and I2L channels to provide 200uA of current to the serial port COMA of the multiplexer switch MAX4052AESE chip, and the serial communication interface COMB of the multiplexer switch MAX4052AESE chip is connected and sends the signal to the INA118U high-precision instrument-level differential amplifier chip, and the voltage value VO output by the INA118U high-precision instrument-level differential amplifier chip enters the MCU from the terminal AD_T for AD sampling.

[0028] This constant current source high-precision multi-channel temperature control system overcomes the adverse effects of the existing NTC thermistor used in the reaction disk of the fully automatic biochemical analyzer as a multi-channel acquisition front end on the accuracy and stability of the monitoring data. It can realize real-time monitoring of multiple temperatures to obtain the temperature values ​​of multiple points on the reagent disk. At the same time, it uses a high-precision temperature probe, combined with a high-precision constant current source input and differential amplification to form an acquisition front end, ensuring subsequent accurate and stable 16-bit AD sampling, thereby greatly improving the accuracy and stability of the temperature monitoring data.

[0029] The above description shows the main features, basic principles, and advantages of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments or embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model. Therefore, the above embodiments or embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the utility model. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0030] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A constant current source high-precision multi-channel temperature control system, characterized by: The invention comprises a microprocessor (1), a reference voltage source (2) for supplying power to the microprocessor (1), and a front-end acquisition unit (3) for collecting temperature signals and sending the signals to the microprocessor (1), wherein the front-end acquisition unit (3) is connected to a signal input terminal of the microprocessor (1), and the reference voltage source (2) is connected to a power supply input terminal of the microprocessor (1); wherein: The front-end acquisition unit (3) comprises a plurality of temperature probes (31), a multiplexing switch (32), a signal amplifier (33), a constant current source module (34), and filter connectors (35) corresponding to the temperature probes (31) one by one, each of the temperature probes (31) being connected to each signal input end of the multiplexing switch (32) via a corresponding connector (35), a serial communication interface of the multiplexing switch (32) being connected to a signal input end of the microprocessor (1) via the signal amplifier (33), and the constant current source module (34) being connected to another serial port of the multiplexing switch (32); The temperature probe (31) adopts a PT1000 temperature sensor; the multiplexing switch (32) adopts a MAX4052AESE multiplexing switch; the signal amplifier (33) adopts an INA118U high-precision instrument-grade differential amplifier chip; the constant current source module (34) adopts a REF200 high-precision constant current source chip; the filter connector (35) adopts a B03B-PASK-1 connector; and the microprocessor (1) adopts an STM32F373CBT6 processing chip.

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