WIRELESS PROCESS VARIABLE TRANSMITTER HAVING REMOVABLE POWER MODULE - Patent application

Abstract

A wireless process variable transmitter (10) for use in an industrial process includes a process variable sensor (40) configured to sense a process variable of an industrial process. A measurement circuit (42) connected to the process variable sensor provides an output related to the sensed process variable (40). A wireless communication circuit (48) connected to the measurement circuit (42) wirelessly transmits information related to the sensed process variable to a remote location. A removable industrial power module (12) holds a replaceable battery (50) and is configured to power the process variable sensor (40), the measurement circuit (42), and the wireless communication circuit (48). A battery test circuit (54) within the removable industrial power module (12) connects to the replaceable battery (50) and provides a visual output related to the status of the replaceable battery (50).

Description

[Technical field]

[0001] The present invention relates to a wireless process variable transmitter having a removable power module. [Background technology]

[0002] In industrial environments, control systems are used to monitor and control the current state of industrial and chemical processes. Typically, control systems perform these functions using a large number of field devices distributed at key locations throughout the industrial process. The field devices may operate in a variety of different facilities. Examples of process facilities include petroleum, pharmaceutical, chemical, pulp, and other processing facilities. These field devices are communicatively connected to control circuits in a control room.

[0003] Field devices are used by the process control measurement industry for a variety of purposes. Typically, such devices have field-hardened enclosures so that they can be installed outdoors in relatively rugged environments and can withstand climatological extremes of temperature, humidity, vibration, and mechanical shock. Field devices also typically operate on relatively low power. For example, there are several field devices currently available that receive all of their operating power from the well-known 4-20 mA loop.

[0004] Traditionally, field devices have been connected to process communication systems (such as a control room) by physical conductors. Such wired connections not only provide power to the field equipment, but also provide a route for communication. One limitation with wired field devices is that installation can sometimes be labor intensive, as wires must be run to each physical location of the field device.

[0005] More recently, field devices have emerged that use wireless communication to communicate with a control room and / or other suitable devices. These wireless field devices typically include an internal power source, such as a battery, that can provide operating power to the wireless field device for several years. Exemplary wireless communication standards include WirelessHART (registered trademark) (IEC 62591) or ISA 100.11a (IEC 62734), or another wireless communication protocol, e.g., WiFi, LoRa, Sigfox, BLE, or any other suitable protocol, including a custom communication protocol.

[0006] The use of wireless technology in the industrial process industries has created a need for a way to locally power wireless transmitters. Batteries are one way that local power can be provided. However, one problem with batteries is that they may need to be replaced. Summary of the Invention

[0007] A wireless process variable transmitter for use in an industrial process includes a process variable sensor configured to sense a process variable of an industrial process. A measurement circuit connected to the process variable sensor provides an output related to the sensed process variable. A wireless communication circuit connected to the measurement circuit wirelessly transmits information related to the sensed process variable to a remote location. A removable industrial power module holds a replaceable battery and is configured to power the process variable sensor, the measurement circuit, and the wireless communication circuit. A battery test circuit in the removable industrial power module connects to the replaceable battery and provides a visual output related to the status of the replaceable battery.

[0008] This Summary is provided to introduce in a simplified form a selection of concepts that are further described in the Formulation for Carrying Out the Invention below. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended for use as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all of the shortcomings noted in the Background. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a partially exploded perspective view of a wireless field device including a removable industrial power module according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a simplified block diagram of the electrical circuitry of the wireless transmitter of FIG. [Diagram 3] FIG. 3 is a schematic diagram of a battery test circuit of the wireless field device of FIG. 1 according to one exemplary embodiment. [Figure 4] 4A-4E illustrate the operation of a removable industrial power module according to one exemplary configuration. [Figure 5A] FIG. 5A illustrates the operation of a mechanical reset indicator for use in a removable industrial power module. [Figure 5B] FIG. 5B illustrates the operation of a mechanical reset indicator for use with a removable industrial power module. [Figure 5C] FIG. 5C illustrates the operation of a mechanical reset indicator for use with a removable industrial power module. [Figure 5D] FIG. 5D illustrates the operation of a mechanical reset indicator for use in a removable industrial power module. [Figure 6A] FIG. 6A is a perspective view of a removable industrial power module having a hinged cover or cap that connects to the body. [Figure 6B]FIG. 6B is a perspective view of a removable industrial power module having a hinged cover or cap that connects to the body. [Figure 7A] FIG. 7A is a perspective view of the upper circuit board of the removable industrial power module. [Figure 7B] FIG. 7B is a perspective view of the lower or bottom circuit board of the removable industrial power module. [Figure 8] FIG. 8 is a simplified schematic diagram showing a battery test circuit in a removable industrial power module including an operator operated switch. [Figure 9] FIG. 9 is a simplified schematic diagram showing a battery test circuit in a removable industrial power module that includes an astable multivibrator circuit for flashing an LED or other display as desired. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] It is desirable to allow an operator to replace a worn-out battery in a removable industrial power module with a fresh battery that is off the shelf. However, there are problems with the replacement battery, and the operator may not know if the new battery they just installed is working properly, installed correctly, or if the battery pack assembly is functioning properly. One way to test the battery pack is by connecting the battery pack to a handheld communicator after the power module is replaced in the field device. Furthermore, the operator can wait to see if the field device can rejoin the wireless network. However, this requires additional testing, the testing must be done in the field, and may result in damage to components of the field device. In various aspects, a removable battery pack is provided for a wireless process variable transmitter for use in an industrial process. The removable battery pack includes a replaceable battery along with a battery test circuit to test the replaceable battery and ensure proper operation of the removable battery pack.

[0011] FIG. 1 is a front exploded perspective view of a wireless field device (wireless process variable transmitter) 10 connected to a removable industrial power module (external battery pack) 12, according to an embodiment of the present invention. The field device 10 generally includes a sensor module 14 that is mountable proximate to a process installation. One or more sensors disposed within or connected to the sensor module 14 provide electrical indications for the process. Examples of sensors include absolute, gauge, and / or differential pressure sensors, as well as temperature sensors, acoustic sensors, and other suitable devices. The sensor module 14 is connected to an electronics compartment 16 that houses electronics for processing or converting electrical signals received from the one or more sensors into usable information that can be communicated to other devices. The electronics compartment 16 generally includes communication circuitry, such as wireless communication (I / O) circuitry that communicates with other devices via an antenna 18. The communication circuitry in the compartment 16 can use the antenna 18 to communicate with a gateway device, or other field devices disposed between the field device 10 and the gateway device, to interact with the gateway device. Wireless field devices are commonly known, and one example of a commercially available wireless field device is the trade designation Model 3051S Wireless available from Emerson Automation Solutions of Chanhassen, Minn. Field device 10 may be one of many field devices deployed in a process installation that may be referred to as a "mesh" network.

[0012] Some wireless field devices, such as wireless field device 10, use an internal battery pack (a removable industrial power module) that lasts for several years. However, when the battery pack's energy is depleted, a technician must typically travel to the physical location of field device 10 to replace the battery pack. The new battery must be properly installed for the field device to function. If the replacement battery is not properly installed or not functioning properly, the wireless process variable transmitter will not function and another technician will have to be dispatched to diagnose the problem.

[0013] According to one embodiment of the present invention, the batteries used to power the field device 10 are placed in a module (removable industrial power module 12) that is received in a module compartment 22 separate from the electronics compartment 16. As shown in FIG. 1, the module compartment 22 is sealed with an end cap 24. Examples of replaceable industrial power modules include the 701PGNKF and 701PBKKF available from Emerson Automation Solutions. These power modules are keyed in such a way that they cannot be misconnected when installed in a field device. Typically, the entire power module is replaced with a new power module. In one aspect, the present invention provides a power module configured to allow an operator to replace its internal battery. However, in such a power module, it is possible for an operator to reverse the polarity of the battery / cell when placing the battery / cell in the power module. If a power module with a battery / cell misconnected is installed in a field device, the field device will not operate. Reverse polarity can cause damage to field device circuitry or other equipment, cause injury, and violate intrinsic safety standards. Additionally, the terminals of a new battery or power module may become corroded and therefore not make good electrical contact with the connectors in the power module, an operator may mistakenly install a bad or otherwise depleted battery, an operator may install a battery with the wrong voltage, or the power module may have some internal fault. In various aspects, the present invention can alert the operator to these conditions.

[0014] FIG. 2 is a simplified block diagram of a process variable transmitter 10, including a process variable sensor 40 configured to sense a process variable, such as pressure, level, flow, etc. The sensor 40 provides an output to a measurement circuit 42, which may include, for example, an analog-to-digital converter, which provides an output related to the sensed process variable to a controller 44, such as a microprocessor. The controller 44 operates according to instructions stored in a memory 46 and communicates using wireless I / O communication circuitry 48 connected to an antenna 18. The controller can wirelessly transmit information related to the sensed process variable using the antenna 18. Similarly, commands can be received from a remote location using the wireless I / O circuitry 48. The controller 44 can also communicate status information, such as an indication that a replaceable battery 50 should be replaced. The battery 50 is connected to a power supply circuit 52 and is used to power the components of the transmitted process variable 10, including, for example, the sensor 40, the measurement circuitry 42, the controller 44, and the wireless I / O circuitry 48. The battery 50 is carried within a removable industrial power module 12 shown in FIG. 1. Also maintained within module 12 is battery test circuitry 54, which is described in more detail below.

[0015] 3 is a schematic diagram showing an example of the configuration of the battery test circuit 54. The circuit 54 is configured to connect to the removable battery 50 and includes a toggle switch 60 and a first resistor connected in series with a green first resistor 62 connected in series with a green LED 64. A second resistor 66 is connected in series with a red LED 68. In FIG. 3, the test circuit 54 provides a power module output that connects to the power supply circuit 52. However, the test circuit 54 can also be connected in parallel with the power supply circuit 52.

[0016] To mitigate the risk of reversed polarity or improperly installed battery potential, the present invention provides a battery test circuit configured to provide an indication that a battery is misconnected.

[0017] After a new battery is installed in the power module 12, an operator mechanically resets the toggle switch 60 to the closed position. Power from the battery 50 is then provided to the power circuit 52. When properly connected, the green LED 64 is forward biased and illuminated, and the red LED 68 is reverse biased and remains off. However, if the cells are installed with reverse polarity, the opposite will happen and the red LED 68 will illuminate.

[0018] 4A-4E illustrate the operation of one configuration of the battery module 12 including a visible reset indicator 90 that can also be used to activate the switch 60. FIG. 4A shows the power module in a closed position with the power module cap 76 sealed to the power module body 74. The LEDs 64 and 68 are visible as is the reset indicator 90. In FIG. 4B, when the power module cap 76 is removed, the reset indicator 90 extends from the body 74, preventing the power module 12 from being placed in the module compartment 22 of the wireless field device 10 shown in FIG. 1. FIG. 4C is an illustration of a power module 12 with one battery 50 inserted with incorrect polarity. When this occurs, as described above, the red LED 68 is illuminated to indicate to the operator that the battery polarity is incorrect. In contrast, in FIG. 4D, the battery 50 is inserted in the correct orientation and the green LED indicator 64 is illuminated. After the battery 50 is properly inserted into the module 12 and the cap 76 is closed, the operator can push the reset indicator 90 back into the body 74, as shown in FIG 4E, thereby disconnecting the LEDs 64 and 68 from the battery 50 to reduce battery drain, which in turn allows the battery module 12 to be inserted into the module chamber 22 shown in FIG 1.

[0019] 5A-5D show the operation of one example of the configuration of the reset indicator 90. As shown in FIG. 5A, with the cover 76 closed, the linkage 102 has a tip 104 that is received in the slot 106 of the reset indicator 90. Thus, the spring 100 is maintained in a compressed state. When the power module cap 76 is opened or removed from the body 74, the linkage 102 can move upward, thereby releasing the reset indicator 90, whereby the spring 100 pushes the reset indicator out of the body 74. Following a battery replacement, the power module cap 76 can be replaced onto the body 74, as shown in FIG. 5C, and the status of the LEDs 64 and 68 can be viewed by an operator. Once the operator has ensured that the polarity of the battery 50 is correct, the reset indicator can be pushed inward and secured by the tip 104 of the linkage 102, as shown in FIG. 5D. In the state shown in FIG. 5D, the module 12 can be placed into the module compartment 22 of the process variable transmitter 10. Additionally, the movement of the reset element 90 can be connected to the switch 60 such that when the reset indicator 90 is pressed inward, as shown in FIG. 5D, the LEDs 64 and 68 are disconnected from the battery 50, thereby preventing battery drain.

[0020] 6A and 6B are further views of an example of a removable industrial power module 12. Figures 6A and 6B are perspective views of a power module cap 76 in a closed and open position. In this example configuration, the power module cap 76 is hinged and secured with a latch.

[0021] 7A is a perspective view of the upper circuit board 110 and FIG. 7B is a perspective view of the lower circuit board 112 configured to mate with both ends of the power module 12. Connectors 120 on the lower circuit board 112 are used to provide electrical connections to the field device 10. Additionally, three wires (not shown) connect the two circuit boards together in the power module 12. The three wires provide a battery positive connection, a battery negative connection, and a communication connection for communicating with a handheld diagnostic device.

[0022] The upper circuit board 110 may include battery test circuitry according to one exemplary embodiment since the two battery terminals are accessible on the upper circuit board 110. Alternatively, the battery test circuitry may be located on the lower circuit board.

[0023] FIG. 8 is a schematic diagram of another exemplary embodiment of the battery test circuit 120. In the configuration of FIG. 8, the circuit may be carried on the upper circuit board 110 since both positive and negative battery connection points are available at that location. A status LED 122 is provided to indicate whether the battery is providing sufficient voltage output to operate the wireless field device 10. A press on the test button 122 may be activated by an operator to connect the battery 50 to the comparison circuit 124. Based on a voltage comparison with a predetermined threshold, an output is provided to the LED 122 via a current limiting resistor 126, thereby indicating that the battery is "good," and the comparison circuit 124 may be configured to operate only if the battery voltage is within a predetermined voltage range. By enabling the test circuit 120 only when the button 122 is activated, battery current is conserved, thereby ensuring that the battery is not drained. An optional second resistor (not shown) may be placed between the battery 50 and the switch 122 to limit the current that can be drawn from the battery 50 for intrinsic safety purposes.

[0024] FIG. 9 is a simplified schematic diagram of another exemplary embodiment of a battery test circuit 120 that provides a continuous visual indication of the battery condition. In the configuration of FIG. 9, the push button 122 of FIG. 8 is not used. Instead, an astable multivibrator circuit 132 is used to periodically energize the LED 122 at a very low duty cycle when enabled by the output from the comparison circuit 124, so that a minimal amount of energy is consumed from the battery. The system blinks the LED 122 at a rate set by the stable multivibrator. The astable multivibrator circuit 132 can be a comparator-based circuit or a transistor-based circuit. The circuit 132 can be set to have a fixed oscillation period of about 5 seconds with an on-time of about 40 milliseconds. The current through the LED 122 can be set to a relatively low value, such as less than 2 mA. This configuration results in an equivalent DC circuit drain from the battery 50 of 12 mA. These parameters can be adjusted as needed. An additional resistor (not shown in FIG. 9) may be placed in series with the battery 50 for the purpose of limiting the current that can be drawn in accordance with inherent safety standards.

[0025] Although the present invention has been described with respect to preferred embodiments, those skilled in the art will recognize that various changes may be made in form and detail without departing from the spirit and scope of the invention. For example, an external battery test terminal may be provided to allow an operator to perform a battery test using an external voltmeter. In the configurations of Figures 8 and 9, additional LEDs may be provided to provide additional information such as indicating higher or lower voltage values, reverse polarity, etc.

Claims

1. 1. A wireless process variable transmitter for use in an industrial process, comprising: a process variable sensor configured to sense a process variable of an industrial process; a measurement circuit coupled to the process variable sensor and configured to provide an output related to a sensed process variable; a wireless communication circuit coupled to the measurement circuit and configured to wirelessly transmit information related to the sensed process variable to a remote location; a removable industrial power module configured to hold a replaceable battery and provide power to the measurement circuitry and the wireless communication circuitry; a battery test circuit disposed within the removable industrial power module configured to connect to the replaceable battery and provide a visual output related to a status of the replaceable battery; 1. A wireless process variable transmitter comprising:

2. 10. The wireless process variable transmitter of claim 1 further comprising a visual indicator coupled to the battery test circuit and providing a visual output related to a condition of the replaceable battery.

3. The wireless process variable transmitter of claim 2 , wherein the visual indicator comprises an LED.

4. The wireless process variable transmitter of claim 2 , wherein the visual indicator is activated periodically to reduce power consumption.

5. 5. The wireless process variable transmitter of claim 4 including an astable multivibrator configured to periodically activate the visual indicator.

6. 10. The wireless process variable transmitter of claim 1, wherein the visual output indicates a polarity of the replaceable battery in the removable industrial power module.

7. The wireless process variable transmitter of claim 1 , wherein the visual output is related to a voltage of the replaceable battery.

8. The wireless process variable transmitter of claim 1 including a switch configured to connect the battery test circuit to the replaceable battery.

9. The wireless process variable transmitter of claim 1 , wherein the battery test circuit compares the voltage of the replaceable battery to a threshold value.

10. The wireless process variable transmitter of claim 1 , wherein the removable industrial power module includes a visible reset indicator.

11. The wireless process variable transmitter of claim 10 , wherein the visible reset indicator is spring loaded.

12. 10. The wireless process variable transmitter of claim 1, wherein a visible reset indicator activates a switch that selectively connects the battery test circuitry to the replaceable battery.

13. The wireless process variable transmitter of claim 1 , wherein a visible reset indicator prevents the removable industrial power module from being placed within a housing of the wireless process variable transmitter.

14. The wireless process variable transmitter of claim 10 , wherein the removable industrial power module includes a cover and the visible reset indicator is activated by removal of the cover.

15. The wireless process variable transmitter of claim 1 , wherein the removable industrial power module includes an upper circuit board and a lower circuit board.

16. 16. The wireless process variable transmitter of claim 15, wherein the battery test circuitry is carried on at least one of the upper circuit board and the lower circuit board.

17. 16. The wireless process variable transmitter of claim 15, wherein the upper circuit board and the lower circuit board are electrically connected.

18. 20. The wireless process variable transmitter of claim 17, wherein the electrical connections between the upper circuit board and the lower circuit board include a positive electrical connection, a negative electrical connection, and a communication connection.

19. 1. A removable industrial power module for use with a wireless process variable transmitter, comprising: an electrical connector configured to connect to the wireless process variable transmitter; a body configured to hold a replaceable battery and to provide power to the measurement circuitry and the wireless communication circuitry of the wireless process variable transmitter via the electrical connector; a battery test circuit disposed within the removable industrial power module configured to connect to the replaceable battery and provide a visual output related to a status of the replaceable battery; 1. A removable industrial power module comprising:

20. 20. The removable industrial power module of claim 19 including a visual indicator coupled to the battery test circuit, the visual indicator providing a visual output related to a condition of the replaceable battery.

21. 21. The removable industrial power module of claim 20, wherein the visual indicator comprises an LED.

22. 21. The removable industrial power module of claim 20, wherein the visual indicator is activated periodically to reduce power consumption.

23. 22. The removable industrial power module of claim 21, comprising an astable multivibrator configured to periodically activate the visual indicator.

24. 20. The removable industrial power module of claim 19, wherein the removable industrial power module includes a visible reset indicator.

25. 25. The removable industrial power module of claim 24, wherein the visible reset indicator is spring loaded.

26. 25. The removable industrial power module of claim 24, wherein the visible reset indicator activates a switch that selectively connects the battery test circuitry to the replaceable battery.

27. 25. The removable industrial power module of claim 24, wherein the visible reset indicator prevents placement of the removable industrial power module within a housing of the wireless process variable transmitter.

28. 20. The removable industrial power module of claim 19, wherein the removable industrial power module includes an upper circuit board and a lower circuit board, and wherein electrical connections between the upper circuit board and the lower circuit board include a positive electrical connection, a negative electrical connection, and a communication connection.

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