Wireless process variable transmitter with removable power module

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 Art

[0002] In an industrial environment, control systems are used to monitor and control the status of industrial and chemical processes. Typically, a control system uses a number of field devices distributed at key locations in an industrial process to perform these functions. Field devices can operate in a variety of different facilities. Examples of process facilities include oil, pharmaceutical, chemical, pulp, and other processing facilities. These field devices are communicatively connected to a control circuit in a control room.

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

[0004] Conventionally, field devices have been connected to a process communication system (such as a control room) by physical conductors. Such a wired connection not only supplies power to the field device but also provides a route for communication. One limitation with wired field devices is that installation can sometimes be labor-intensive because 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 control rooms and / or other suitable devices. These wireless field devices typically have 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® (IEC 62591) or ISA 100.11a (IEC 62734), or any other suitable protocol, including other wireless communication protocols such as WiFi, LoRa, Sigfox, BLE, or custom communication protocols.

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

[0007] A wireless process variable transmitter for use in industrial processes includes a process variable sensor configured to sense process variables of an industrial process. A measuring circuit connected to the process variable sensor provides an output related to the sensed process variable. A wireless communication circuit connected to the measuring 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, measuring circuit, and wireless communication circuit. A battery test circuit within 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 in a simplified form to introduce a selection of concepts that will be further described in the forms for carrying out the invention described below. This summary of the invention is not intended to identify any major or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to any implementation that solves any or all of the defects noted in the background art. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 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. [Figure 2] Figure 2 is a simplified block diagram of the electrical circuit of the wireless transmitter shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram of the battery test circuit for the wireless field device shown in Figure 1, according to one exemplary embodiment. [Figure 4] Figures 4A–4E show the operation of a removable industrial power module in one exemplary configuration. [Figure 5A] Figure 5A shows the operation of a mechanical reset indicator for use in a removable industrial power module. [Figure 5B] Figure 5B shows the operation of a mechanical reset indicator for use in a removable industrial power module. [Figure 5C] Figure 5C shows the operation of a mechanical reset indicator for use in a removable industrial power module. [Figure 5D] Figure 5D shows the operation of a mechanical reset indicator for use in a removable industrial power module. [Figure 6A] Figure 6A is a perspective view of a removable industrial power module having a hinged cover or cap that connects to the main body. [Figure 6B]Figure 6B is a perspective view of a removable industrial power module having a hinged cover or cap that connects to the main body. [Figure 7A] Figure 7A is a perspective view of the upper circuit board of a removable industrial power module. [Figure 7B] Figure 7B is a perspective view of the lower or bottom circuit board of a removable industrial power module. [Figure 8] Figure 8 is a simplified schematic diagram showing a battery test circuit in a removable industrial power module, including a switch operated by an operator. [Figure 9] Figure 9 is a simplified schematic diagram showing a battery test circuit in a removable industrial power module, which includes an astable multivibrator circuit for flashing an LED or other display as desired. [Modes for carrying out the invention]

[0010] It is desirable to allow operators to replace depleted batteries in removable industrial power modules with new, off-the-shelf batteries. However, replacement batteries present problems, and operators may not know if the newly installed battery is working correctly, if it is properly installed, or if the battery pack assembly is functioning correctly. One way to test a battery pack is to connect it to a handheld communicator after the power module has been replaced in the field equipment. Furthermore, the operator can wait to see if the field device can rejoin the wireless network. However, this requires additional testing, must be performed in the field, and may result in damage to components of the field equipment. In various embodiments, removable battery packs are provided for wireless process variable transmitters for use in industrial processes. Removable battery packs include a replaceable battery along with a battery test circuit to test the replaceable battery and ensure the proper operation of the removable battery pack.

[0011] Figure 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 can be mounted in close proximity to the process installation location. One or more sensors located within or connected to the sensor module 14 provide electrical instructions to 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 one or more sensors into usable information that can be transmitted to other devices. The electronics compartment 16 generally includes communication circuits, such as wireless communication (I / O) circuits that communicate with other devices via an antenna 18. The communication circuits within the compartment 16 can communicate with a gateway device, or other field devices located between the field device 10 and the gateway device, using the antenna 18, and interact with the gateway device. Wireless field devices are generally known, and one example of a commercially available wireless field device is the trade name Model 3051S Wireless, available from Emerson Automation Solutions in Chanhassen, Minnesota. 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 the wireless field device 10, use an internal battery pack (removable industrial power module) that lasts for several years. However, when the battery pack's energy is depleted, a technician typically has to travel to the physical location of the field device 10 and replace the battery pack. For the field device to function, the new battery must be properly installed. If the replacement battery is not properly installed or is not functioning correctly, the wireless process variable transmitter will not work, and another technician will need to be dispatched to diagnose the problem.

[0013] According to one embodiment of the present invention, the battery used to power the field device 10 is located in a module (removable industrial power module 12) housed in a module compartment 22 separate from the electronics compartment 16. As shown in Figure 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 a manner that prevents misconnection when installed in the field device. Typically, the entire power module is replaced with a new power module. In one embodiment, 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 into the power module. If a power module with a misconnected battery / cell is installed in a field device, the field device will not function. Reverse polarity can cause damage to the field device circuitry or other equipment, potentially causing injury and violating intrinsic safety standards. Furthermore, the terminals of a new battery or power module may corrode, thereby failing to make good electrical contact with the connectors within the power module; the operator may mistakenly install a faulty or otherwise depleted battery; the operator may install a battery with the wrong voltage; or the power module may have some internal malfunction. In various embodiments, the present invention can warn the operator of these conditions.

[0014] Figure 2 is a simplified block diagram of the process variable transmitter 10, which includes a process variable sensor 40 configured to detect process variables such as pressure, level, and flow rate. The sensor 40 provides an output to a measuring circuit 42, which may include, for example, an analog-to-digital converter, and 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 memory 46 and communicates using a wireless I / O communication circuit 48 connected to an antenna 18. The controller can use the antenna 18 to wirelessly transmit information related to the sensed process variable. Similarly, commands can be received from a remote location using the wireless I / O circuit 48. The controller 44 can also communicate status information, such as an instruction 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 measuring circuit 42, the controller 44, and the wireless I / O circuit 48. The battery 50 is carried within a removable industrial power module 12 shown in Figure 1. The battery test circuit 54, which will be described in more detail below, is also housed within module 12.

[0015] Figure 3 is a schematic diagram showing an example configuration of a battery test circuit 54. The circuit 54 is configured to connect to a removable battery 50 and includes a toggle switch 60 and a first resistor connected in series with a green LED 64 and a green first resistor 62 connected in series with the first resistor 66 connected in series with a red LED 68. In Figure 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 potential of a battery with reversed polarity or improperly installed, the present invention provides a battery test circuit configured to provide an indication that the battery is incorrectly connected.

[0017] After a new battery is attached to the power module 12, the operator mechanically resets the toggle switch 60 to the closed position. Next, power from the battery 50 is supplied to the power circuit 52. When properly connected, the green LED 64 is biased in the forward direction and illuminated, while the red LED 68 is biased in the reverse direction and remains off. However, if the cells are installed with the opposite polarity, the opposite occurs and the red LED 68 lights up.

[0018] Figures 4A - 4E illustrate the operation of one configuration of the battery module 12 that includes a visual reset indicator 90 that can also be used to activate the switch 60. Figure 4A shows the power module with the power module cap 76 in the closed position sealed to the power module body 74. The LEDs 64 and 68 are visible, as is the reset indicator 90. In Figure 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 within the module compartment 22 of the wireless field device 10 shown in Figure 1. Figure 4C is a diagram of the power module 12 with one battery 50 inserted with the wrong polarity. When this occurs, as described above, the red LED 68 lights up, indicating to the operator that the battery polarity is incorrect. In contrast, in Figure 4D, the battery 50 is inserted in the correct direction and the green LED indicator 64 lights up. After properly inserting the battery 50 into the module 12 and closing the cap 76, the operator can push the reset indicator 90 back into the body 74, as shown in Figure 4E, thereby disconnecting the LEDs 64 and 68 from the battery 50 and reducing battery drain. Additionally, this allows the battery module 12 to be inserted into the module chamber 22 shown in Figure 1.

[0019] Figures 5A to 5D show the operation of an example configuration of the reset indicator 90. As shown in Figure 5A, in the state where the cover 76 is closed, the link mechanism 102 has a tip 104 that is received within the slot 106 of the reset indicator 90. Accordingly, the spring 100 is maintained in a compressed state. When the power module cap 76 is opened or removed from the main body 74, the link mechanism 102 can move upward, thereby releasing the reset indicator 90, and thereby the spring 100 pushes the reset indicator out of the main body 74. Following battery replacement, as shown in Figure 5C, the power module cap 76 can be replaced on the main body 74, and the operator can view the states of the LEDs 64 and 68. When it is ensured by the operator that the polarity of the battery 50 is correct, the reset indicator can be pushed inward as shown in Figure 5D and fixed by the tip 104 of the link mechanism 102. In the state shown in Figure 5D, the module 12 can be disposed within 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, as shown in Figure 5D, when the reset indicator 90 is pushed inward, the LEDs 64 and 68 are disconnected from the battery 50, thereby preventing battery drain.

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

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

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

[0023] Figure 8 is a schematic diagram of another exemplary embodiment of the battery test circuit 120. In the configuration of Figure 8, the circuit can be carried on the upper circuit board 110, as both positive and negative battery connection points are available in place. A status LED 122 is provided to indicate whether the battery is providing a voltage output sufficient to operate the wireless field device 10. Pressing the test button 122 can be actuated by an operator to connect the battery 50 to the comparator 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 comparator circuit 124 may be configured to operate only when the battery voltage is within a predetermined voltage range. By enabling the test circuit 120 only when the button 122 is actuated, battery current is conserved, thereby ensuring that the battery is not depleted. An optional second resistor (not shown) can 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] Figure 9 is a simplified schematic diagram of another exemplary embodiment of the battery test circuit 120 that provides a continuous visual display of the battery status. In the configuration of Figure 9, the push button 122 of Figure 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 comparator circuit 124, resulting in minimal energy being consumed from the battery. The system causes the LED 122 to flash 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 of 12 mA from the battery 50. These parameters can be adjusted as needed. Additional resistors (not shown in Figure 9) may be placed in series with the battery 50 to limit the current that can be drawn in accordance with specific safety standards.

[0025] While the present invention has been described in relation to preferred embodiments, those skilled in the art will recognize that various modifications may be made to the form and details without departing from the spirit and scope of the invention. For example, an external battery test terminal may be provided so that an operator can perform battery testing 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. A wireless process variable transmitter for use in industrial processes, A process variable sensor configured to sense process variables in an industrial process, A measurement circuit connected to the process variable sensor, configured to provide an output related to the detected process variable, A wireless communication circuit connected to the measurement circuit is 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 to supply power to the measurement circuit and the wireless communication circuit, Equipped with, The aforementioned removable industrial power module is A battery test circuit, configured to connect to the replaceable battery and provide a visual output related to the status of the replaceable battery, is located within the removable industrial power module. A visible reset indicator, Cover and contents, The visible reset indicator is activated by removing the cover. Wireless process variable transmitter.

2. The wireless process variable transmitter according to claim 1, comprising a visual indicator connected to the battery test circuit and providing a visual output related to the status of the replaceable battery.

3. The wireless process variable transmitter according to claim 2, wherein the visual indicator includes an LED.

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

5. The wireless process variable transmitter according to claim 4, comprising an astable multivibrator configured to periodically activate the visual indicator.

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

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

8. The wireless process variable transmitter according to claim 1, comprising a switch configured to connect the battery test circuit to the replaceable battery.

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

10. The wireless process variable transmitter according to claim 1, wherein the visible reset indicator is of the spring load type.

11. The wireless process variable transmitter according to claim 1, wherein a visible reset indicator activates a switch that selectively connects the battery test circuit to the replaceable battery.

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

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

14. The wireless process variable transmitter according to claim 13, wherein the battery test circuit is supported on at least one of the upper circuit board and the lower circuit board.

15. The wireless process variable transmitter according to claim 13, wherein the upper circuit board and the lower circuit board are electrically connected.

16. The wireless process variable transmitter according to claim 15, wherein the electrical connection between the upper circuit board and the lower circuit board includes a positive electrical connection, a negative electrical connection, and a communication connection.

17. A removable industrial power module for use with a wireless process variable transmitter, An electrical connector configured to connect to the wireless process variable transmitter, A main unit configured to hold a replaceable battery and supply power to the measurement circuit and wireless communication circuit of the wireless process variable transmitter via an electrical connector, A battery test circuit, configured to connect to the replaceable battery and provide a visual output related to the status of the replaceable battery, is located within the removable industrial power module. A visible reset indicator, Equipped with a cover, The visible reset indicator is activated by removing the cover. Removable industrial power module.

18. A removable industrial power module according to claim 17, comprising a visual indicator connected to the battery test circuit, the visual indicator providing a visual output related to the status of the replaceable battery.

19. The removable industrial power module according to claim 18, wherein the visual indicator includes an LED.

20. The removable industrial power module according to claim 18, wherein the visual indicator is periodically activated to reduce power consumption.

21. A removable industrial power module according to claim 19, comprising an astable multivibrator configured to periodically activate the visual indicator.

22. The removable industrial power module according to claim 17, wherein the visible reset indicator is spring-loaded.

23. The removable industrial power module according to claim 17, wherein the visible reset indicator activates a switch that selectively connects the battery test circuit to the replaceable battery.

24. The removable industrial power module according to claim 17, wherein the visible reset indicator prevents the removable industrial power module from being placed inside the housing of the wireless process variable transmitter.

25. The removable industrial power module according to claim 17, wherein the removable industrial power module includes an upper circuit board and a lower circuit board, and 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.

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