JP2020115245A - Transmission unit state diagnosis device and method, and field device - Google Patents

Abstract

To diagnose a transmission unit state of a communication circuit at low cost.SOLUTION: A communication control unit 11 and a diagnosis unit 13 are provided as processing functions of a CPU. The diagnosis unit 13 monitors the level of the transmission signal from a transmission unit 21 of a communication circuit 2, and diagnoses the normal/abnormal state of the transmission unit 21 of the communication circuit 2 based on the change in the level of the transmission signal when the communication control unit 11 changes the transmission unit 21 from the non-communication state to the communication state.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transmitter state diagnosis device and method, and a field device, and particularly to a transmitter state diagnosis device and method for diagnosing the state of a transmitter part of a communication circuit mounted in a field device, and a transmitter part of a communication circuit. The present invention relates to a field device having a function of diagnosing a condition.

2. Description of the Related Art Conventionally, a field device such as an electric control valve or a positioner having a flow rate control function has a CPU (Central Processing Unit) that performs predetermined arithmetic processing based on a control signal from a controller or a detection signal from various sensors, A communication circuit that transmits/receives signals to/from an external device such as a controller or a monitoring device is mounted. Among them, the communication circuit includes a receiving unit that receives a signal from an external device and a transmitting unit that transmits the data calculated by the CPU to the external device (for example, see Patent Document 1).

JP-A-1-141202

However, since the conventional field device is not provided with the function of diagnosing the normal/abnormal state of the transmission unit of the communication circuit, it is possible to perform a failure diagnosis of the transmission unit at the so-called operating end, that is, the field device side. could not. To diagnose the normal/abnormal state of the transmission unit, for example, a method of diagnosing the state of the transmission unit by feeding back all transmission signals from the transmission unit and diagnosing the protocol is considered. To be However, in order to realize this, the CPU is required to have the ability to process the diagnosis of the protocol, resulting in a high cost.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a transmitter state diagnosis device and method capable of diagnosing the state of a transmitter of a communication circuit at low cost, and a method. To provide field devices.

In order to achieve such an object, the present invention provides a communication control unit (11) configured to control a transmission unit (21) of a communication circuit (2), and a transmission signal transmitted from the transmission unit. A diagnostic configured to monitor the level and diagnose the state of the transmission unit based on a change in the level of the transmission signal when the communication control unit changes the transmission unit from the non-communication state to the communication state. And a part (13).

In the present invention, the state of the transmission unit is diagnosed by capturing only the change in the level of the transmission signal when the communication control unit changes the transmission unit from the non-communication state to the communication state. For example, when the transmitter is in the communication state, the level of the transmission signal does not change from the level when the transmitter is in the non-communication state, even though the data to be transmitted is sent to the transmitter. It is diagnosed that the state of the transmitter is abnormal.

In the above description, as an example, the constituent elements in the drawings corresponding to the constituent elements of the invention are indicated by reference numerals in parentheses.

As described above, according to the present invention, since the communication control unit need only capture the change in the level of the transmission signal when the transmission unit is changed from the non-communication state to the communication state, CPU power is not required, The state of the transmitter of the communication circuit can be diagnosed at low cost.

FIG. 1 is a diagram showing a main part of a field device including a transmitter state diagnosis device according to a first embodiment of the present invention. FIG. 2 is a flow chart for explaining the characteristic operation of this field device. FIG. 3 is a diagram showing a main part of a field device including a transmitter state diagnosis device according to a second embodiment of the present invention. FIG. 4 is a diagram showing an example in which a diagnostic unit is provided in a cloud-side server connected to a field device via a network.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a main part of a field device 100 including a transmitter state diagnosis device 200 according to the first embodiment of the present invention.

The field device 100 is realized by hardware including a CPU and a storage device and a program that realizes various functions in cooperation with the hardware, and includes a computing device (CPU) 1, a communication circuit 2, and a storage device. And a device (buffer) 3.

In this field device 100, the arithmetic device 1 includes a communication control unit 11, an arithmetic processing unit 12, and a diagnosis unit 13 as processing functions of the CPU. The communication circuit 2 also includes a transmitter 21 that sends a transmission signal to an external device (not shown) through the output line L1 and a receiver 22 that receives a reception signal from the external device through the input line L2.

In the arithmetic device 1, the communication control unit 11 controls the transmission unit 21 of the communication circuit 2. The arithmetic processing unit 12 executes various arithmetic processes based on detection signals from the various sensors 501, operation signals from the operation device 502, and the like. The data processed by the calculation processing unit 12 and the like are stored in the storage device 3. When the data to be transmitted is generated, the communication control unit 11 sets the transmission unit 21 in the communication state, reads the data from the storage device 3 and sends the data to the transmission unit 21, and the transmission unit 21 outputs the transmission line L1 as a transmission signal. Through an external device.

In the arithmetic unit 1, the diagnosis unit 13 monitors the level of the transmission signal transmitted from the transmission unit 21, and detects the level of the transmission signal when the communication control unit 11 changes the transmission unit 21 from the non-communication state to the communication state. The state of the transmitter 21 is diagnosed based on the change. Specifically, when the transmission unit 21 is in the communication state, the level of the transmission signal changes when the transmission unit 21 is in the non-communication state even though the data to be transmitted is sent to the transmission unit 21. When the level does not change, it is diagnosed that the state of the transmission unit 21 is abnormal.

In this field device 100, the transmission unit state diagnosis device 200 includes a communication control unit 11 and a diagnosis unit 13. In the transmitter state diagnosis device 200, when the data to be transmitted is generated, the communication control unit 11 sets the transmitter 21 of the communication circuit 2 in the communication state, reads the data from the storage device 3, and transmits the data to the communication circuit 2. It is sent to the unit 21 (step S101 shown in FIG. 2). At the same time, the communication control unit 11 notifies the diagnosis unit 13 that the data to be transmitted has been sent to the transmission unit 21 of the communication circuit 2 (step S102).

Here, if the transmission unit 21 of the communication circuit 2 is normal, the transmission unit 21 outputs the data as a transmission signal until a predetermined time T elapses after receiving the data to be transmitted. That is, when the level of the transmission signal from the transmission unit 21 is maintained at the “L” level when the transmission unit 21 is in the non-communication state, the level of the transmission signal from the transmission unit 21 changes. That is, the level changes from the “L” level to the “H” level and from the “H” level to the “L” level.

The diagnostic unit 13 receives the notification from the communication control unit 11 that the data has been sent to the transmission unit 21 (step S102), and after the waiting time TW defined as the predetermined time T has elapsed (step S103), It is checked whether the level of the transmission signal from the transmission unit 21 has changed from the level when the transmission unit 21 is in the non-communication state (idle state) (step S104). Specifically, the voltage VP1 of the output line L1 to which the transmission signal from the transmission unit 21 is output is monitored, and this voltage (hereinafter, referred to as a monitoring voltage) VP1 when the transmission unit 21 is in the non-communication state. Check whether the value has changed.

As described above, if the transmitter 21 of the communication circuit 2 is normal, the transmitter 21 outputs the data as a transmission signal until the predetermined time T elapses after receiving the data to be transmitted. To do. As a result, the transmission signal from the transmission unit 21 changes from the state in which the “L” level has been maintained until then to a state in which the level changes.

When the diagnosis unit 13 confirms that the level of the transmission signal has changed from the level when the transmission unit 21 is in the non-communication state after the lapse of the waiting time TW in step S103 (YES in step S104), the communication circuit 2 The transmitting unit 21 of the above diagnoses that it is normal (step S105).

On the other hand, when it is confirmed that the level of the transmission signal does not change from the level when the transmission unit 21 is in the non-communication state, even though the waiting time TW has elapsed (NO in step S104), the diagnosis unit 13 The transmission unit 21 of the communication circuit 2 is diagnosed as abnormal (step S106).

As described above, according to the present embodiment, since the communication control unit 11 needs only to capture the change in the level of the transmission signal when the transmission unit 21 is changed from the non-communication state to the communication state, it requires no CPU power. Instead, the state of the transmitter 21 of the communication circuit 2 can be diagnosed at low cost. Further, since it is only necessary to detect the change in the level of the transmission signal, it can be applied to various types of communication and is versatile.

In the example shown in FIG. 1, when the transmission unit 21 is in the non-communication state, the level of the transmission signal from the transmission unit 21 is maintained at the “L” level. It may be maintained. Also in this case, the normal/abnormal state of the transmitter 21 of the communication circuit 2 is diagnosed in the same manner as described above.

[Second Embodiment]
FIG. 3 shows a main part of a field device 101 including a transmitter state diagnosis device 201 according to the second embodiment of the present invention. In the transmitter state diagnosis device 201 according to the present embodiment, the level conversion circuit 4 is provided in order to match the monitoring voltage VP1 with the voltage that the diagnosis unit 13 can recognize (the voltage that the CPU can recognize).

In the transmitter state diagnosis device 201, the level conversion circuit 4 is composed of a transistor Tr1 and resistors R1 and R2. The collector of the transistor Tr1 is connected to the input line of the power supply voltage Vcc via the resistor R1. The emitter of the transistor Tr1 is grounded, and the base of the transistor Tr1 is connected to the output line L1 via the resistor R2. The voltage generated at the connection point P1 between the resistor R1 and the collector of the transistor Tr1 is sent to the diagnosis unit 13 as the monitoring voltage VP1.

When the transmission unit 21 is in the non-communication state and the level of the transmission signal from the transmission unit 21 is maintained at the “L” level, the “L” level voltage generated in the output line L1 is level-converted. It is given to the base of the transistor Tr1 via the resistor R2 of the circuit 4. As a result, the transistor Tr1 is turned off, and while the level of the transmission signal from the transmission unit 21 maintains the “L” level, the diagnosis unit 13 has a connection point P1 between the resistor R1 and the collector of the transistor Tr1. The generated power supply voltage Vcc is applied as the monitoring voltage VP1.

On the other hand, when the transmission unit 21 is in the communication state and the level of the transmission signal from the transmission unit 21 maintains the "L" level up to then, a level change occurs, which occurs in the output line L1. The “H” level voltage is applied to the base of the transistor Tr1 via the resistor R2 of the level conversion circuit 4. As a result, the transistor Tr1 is turned on, and the diagnostic unit 13 is supplied with the ground potential as the monitoring voltage VP1.

When the transmitting unit 21 is in the communication state and the data to be transmitted is sent to the transmitting unit 21, the diagnostic unit 13 determines that the monitoring voltage VP1 does not change from the power supply voltage Vcc to the ground potential. It is diagnosed that the state of 21 is abnormal. Since the basic operation of the diagnosis unit 13 is the same as that of the first embodiment, detailed description thereof will be omitted.

Although the circuit configuration using the transistor Tr1 as the level conversion circuit 4 is shown in this embodiment, any type of switching element such as JFET or MOSFET may be used.

[Third Embodiment]
FIG. 4 shows a main part of a network system 600 including a transmitter state diagnosis device 202 according to the third embodiment of the present invention. In this network system 600, the diagnosis unit 13 is provided in the cloud-side server 400 connected to the field device 102 via the network 300.

Further, in this network system 600, the interface (I/F) 5 is provided in the field device 102, and the level of the transmission signal from the transmission unit 21 in the communication circuit 2 or the communication control unit 11 in the arithmetic unit 1 controls the transmission unit 21. Information or the like notifying that the communication state has been changed from the non-communication state is sent to the diagnosis unit 13 in the server 400 on the cloud side via the network 300.

In this network system 600, the transmission unit state diagnosis device 202 is composed of a communication control unit 11 in the arithmetic unit 1 provided on the field device 102 side and a diagnosis unit 13 provided on the cloud side server 400. ing. In the server 400 on the cloud side, the diagnosis unit 13 is provided as a processing function of the CPU. The basic operation of the diagnosis unit 13 in the cloud-side server 400 is the same as that in the first embodiment, and thus detailed description thereof will be omitted.

The diagnosis result of the diagnosis unit 13 in the cloud-side server 400 may be returned to the field device 102 via the network 300, or may be sent to the user's terminal connected to the network 300. Good.

[Expansion of Embodiment]
Although the present invention has been described with reference to the exemplary embodiments, the present invention is not limited to the above exemplary embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the technical idea of the present invention.

1... Arithmetic device, 2... Communication circuit, 3... Storage device, 4... Level conversion circuit, 11... Communication control part, 12... Arithmetic processing part, 13... Diagnostic part, 21... Transmitting part, 100, 101, 102... Field Equipment, 200, 201, 202... Transmitter state diagnostic device, 300... Network, 400... Cloud side server, 600... Network system, Tr1... Transistor, VP1... Monitoring voltage.

Claims (9)

A communication controller configured to control the transmitter of the communication circuit,
The level of the transmission signal sent from the transmission unit is monitored, and based on the change in the level of the transmission signal when the communication control unit changes the transmission unit from the non-communication state to the communication state, And a diagnostic unit configured to diagnose the condition. In the transmitter state diagnosis device according to claim 1,
The diagnostic unit is
When the transmitter is in the communication state, the level of the transmission signal does not change from the level when the transmitter is in the non-communication state, although the data to be transmitted is sent to the transmitter. In this case, the transmitter state diagnosis device is configured to diagnose that the state of the transmitter is abnormal. The transmitter state diagnosis device according to claim 1 or 2,
The transmitter state diagnosis device, wherein the communication control unit and the diagnosis unit are realized by one arithmetic device. The transmitter state diagnosis device according to claim 1 or 2,
The transmission unit and the communication control unit,
Provided in one field device,
The diagnostic unit is
A transmitter state diagnosis device provided in a server connected to the field device via a network. The transmitter state diagnosis device according to any one of claims 1 to 4,
The transmitter state diagnosis device further comprising: a level conversion circuit configured to convert the level of a transmission signal sent from the transmitter and send the level to the diagnostic unit. A communication control step of controlling the transmitter of the communication circuit,
The level of the transmission signal sent from the transmission unit is monitored, and based on the change in the level of the transmission signal when the transmission unit is changed from the non-communication state to the communication state by the communication control step, And a diagnostic step for diagnosing the condition. The transmitter state diagnosis method according to claim 6,
The diagnostic step is
When the transmitter is in the communication state, the level of the transmission signal does not change from the level when the transmitter is in the non-communication state, although the data to be transmitted is sent to the transmitter. In this case, it is diagnosed that the state of the transmitter is abnormal. A communication circuit including at least a transmitter for transmitting data to the outside;
An arithmetic processing unit that executes various arithmetic processes, a communication control unit that controls the transmission unit of the communication circuit, and a level of a transmission signal transmitted from the transmission unit are monitored, and the communication control unit controls the transmission unit. An arithmetic unit configured to operate as a diagnostic unit that diagnoses the state of the transmission unit based on a change in the level of the transmission signal when the communication state is changed from the non-communication state,
At least a storage device configured to store data arithmetically processed by the arithmetic device,
The field device, wherein the transmission unit is controlled by the communication control unit and is configured to transmit the data stored in the storage device. The field device according to claim 8,
The diagnostic unit is
When the transmitter is in the communication state, the level of the transmission signal does not change from the level when the transmitter is in the non-communication state, although the data to be transmitted is sent to the transmitter. In this case, the field device is configured to diagnose that the state of the transmission unit is abnormal.

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