diag_message — Diagnostic Modbus Messages

API Documentation

Diagnostic Record Read/Write

These need to be tied into a the current server context or linked to the appropriate data

class pymodbus.diag_message.DiagnosticStatusRequest(**kwargs)

This is a base class for all of the diagnostic request functions

__init__(**kwargs)

Base initializer for a diagnostic request

decode(data)

Base decoder for a diagnostic request

Parameters:data – The data to decode into the function code

encode()

Base encoder for a diagnostic response we encode the data set in self.message

Returns:The encoded packet

get_response_pdu_size()

Func_code (1 byte) + Sub function code (2 byte) + Data (2 * N bytes) :return:

class pymodbus.diag_message.DiagnosticStatusResponse(**kwargs)

This is a base class for all of the diagnostic response functions

It works by performing all of the encoding and decoding of variable data and lets the higher classes define what extra data to append and how to execute a request

__init__(**kwargs)

Base initializer for a diagnostic response

decode(data)

Base decoder for a diagnostic response

Parameters:data – The data to decode into the function code

encode()

Base encoder for a diagnostic response we encode the data set in self.message

Returns:The encoded packet

class pymodbus.diag_message.DiagnosticStatusSimpleRequest(data=0, **kwargs)

A large majority of the diagnostic functions are simple status request functions. They work by sending 0x0000 as data and their function code and they are returned 2 bytes of data.

If a function inherits this, they only need to implement the execute method

__init__(data=0, **kwargs)

General initializer for a simple diagnostic request

The data defaults to 0x0000 if not provided as over half of the functions require it.

Parameters:data – The data to send along with the request

execute(*args)

Base function to raise if not implemented

class pymodbus.diag_message.DiagnosticStatusSimpleResponse(data=0, **kwargs)

A large majority of the diagnostic functions are simple status request functions. They work by sending 0x0000 as data and their function code and they are returned 2 bytes of data.

__init__(data=0, **kwargs)

General initializer for a simple diagnostic response

Parameters:data – The resulting data to return to the client

class pymodbus.diag_message.ReturnQueryDataRequest(message=0, **kwargs)

The data passed in the request data field is to be returned (looped back) in the response. The entire response message should be identical to the request.

__init__(message=0, **kwargs)

Initializes a new instance of the request

Parameters:message – The message to send to loopback

execute(*args)

Executes the loopback request (builds the response)

Returns:The populated loopback response message

class pymodbus.diag_message.ReturnQueryDataResponse(message=0, **kwargs)

The data passed in the request data field is to be returned (looped back) in the response. The entire response message should be identical to the request.

__init__(message=0, **kwargs)

Initializes a new instance of the response

Parameters:message – The message to loopback

class pymodbus.diag_message.RestartCommunicationsOptionRequest(toggle=False, **kwargs)

The remote device serial line port must be initialized and restarted, and all of its communications event counters are cleared. If the port is currently in Listen Only Mode, no response is returned. This function is the only one that brings the port out of Listen Only Mode. If the port is not currently in Listen Only Mode, a normal response is returned. This occurs before the restart is executed.

__init__(toggle=False, **kwargs)

Initializes a new request

Parameters:toggle – Set to True to toggle, False otherwise

execute(*args)

Clear event log and restart

Returns:The initialized response message

class pymodbus.diag_message.RestartCommunicationsOptionResponse(toggle=False, **kwargs)

The remote device serial line port must be initialized and restarted, and all of its communications event counters are cleared. If the port is currently in Listen Only Mode, no response is returned. This function is the only one that brings the port out of Listen Only Mode. If the port is not currently in Listen Only Mode, a normal response is returned. This occurs before the restart is executed.

__init__(toggle=False, **kwargs)

Initializes a new response

Parameters:toggle – Set to True if we toggled, False otherwise

class pymodbus.diag_message.ReturnDiagnosticRegisterRequest(data=0, **kwargs)

The contents of the remote device’s 16-bit diagnostic register are returned in the response

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnDiagnosticRegisterResponse(data=0, **kwargs)

The contents of the remote device’s 16-bit diagnostic register are returned in the response

class pymodbus.diag_message.ChangeAsciiInputDelimiterRequest(data=0, **kwargs)

The character ‘CHAR’ passed in the request data field becomes the end of message delimiter for future messages (replacing the default LF character). This function is useful in cases of a Line Feed is not required at the end of ASCII messages.

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ChangeAsciiInputDelimiterResponse(data=0, **kwargs)

The character ‘CHAR’ passed in the request data field becomes the end of message delimiter for future messages (replacing the default LF character). This function is useful in cases of a Line Feed is not required at the end of ASCII messages.

class pymodbus.diag_message.ForceListenOnlyModeRequest(data=0, **kwargs)

Forces the addressed remote device to its Listen Only Mode for MODBUS communications. This isolates it from the other devices on the network, allowing them to continue communicating without interruption from the addressed remote device. No response is returned.

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ForceListenOnlyModeResponse(**kwargs)

Forces the addressed remote device to its Listen Only Mode for MODBUS communications. This isolates it from the other devices on the network, allowing them to continue communicating without interruption from the addressed remote device. No response is returned.

This does not send a response

__init__(**kwargs)

Initializer to block a return response

class pymodbus.diag_message.ClearCountersRequest(data=0, **kwargs)

The goal is to clear ll counters and the diagnostic register. Also, counters are cleared upon power-up

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ClearCountersResponse(data=0, **kwargs)

The goal is to clear ll counters and the diagnostic register. Also, counters are cleared upon power-up

class pymodbus.diag_message.ReturnBusMessageCountRequest(data=0, **kwargs)

The response data field returns the quantity of messages that the remote device has detected on the communications systems since its last restart, clear counters operation, or power-up

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnBusMessageCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages that the remote device has detected on the communications systems since its last restart, clear counters operation, or power-up

class pymodbus.diag_message.ReturnBusCommunicationErrorCountRequest(data=0, **kwargs)

The response data field returns the quantity of CRC errors encountered by the remote device since its last restart, clear counter operation, or power-up

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnBusCommunicationErrorCountResponse(data=0, **kwargs)

The response data field returns the quantity of CRC errors encountered by the remote device since its last restart, clear counter operation, or power-up

class pymodbus.diag_message.ReturnBusExceptionErrorCountRequest(data=0, **kwargs)

The response data field returns the quantity of modbus exception responses returned by the remote device since its last restart, clear counters operation, or power-up

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnBusExceptionErrorCountResponse(data=0, **kwargs)

The response data field returns the quantity of modbus exception responses returned by the remote device since its last restart, clear counters operation, or power-up

class pymodbus.diag_message.ReturnSlaveMessageCountRequest(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device, or broadcast, that the remote device has processed since its last restart, clear counters operation, or power-up

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnSlaveMessageCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device, or broadcast, that the remote device has processed since its last restart, clear counters operation, or power-up

class pymodbus.diag_message.ReturnSlaveNoResponseCountRequest(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device, or broadcast, that the remote device has processed since its last restart, clear counters operation, or power-up

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnSlaveNoReponseCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device, or broadcast, that the remote device has processed since its last restart, clear counters operation, or power-up

class pymodbus.diag_message.ReturnSlaveNAKCountRequest(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device for which it returned a Negative Acknowledge (NAK) exception response, since its last restart, clear counters operation, or power-up. Exception responses are described and listed in section 7 .

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnSlaveNAKCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device for which it returned a Negative Acknowledge (NAK) exception response, since its last restart, clear counters operation, or power-up. Exception responses are described and listed in section 7.

class pymodbus.diag_message.ReturnSlaveBusyCountRequest(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device for which it returned a Slave Device Busy exception response, since its last restart, clear counters operation, or power-up.

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnSlaveBusyCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device for which it returned a Slave Device Busy exception response, since its last restart, clear counters operation, or power-up.

class pymodbus.diag_message.ReturnSlaveBusCharacterOverrunCountRequest(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device that it could not handle due to a character overrun condition, since its last restart, clear counters operation, or power-up. A character overrun is caused by data characters arriving at the port faster than they can be stored, or by the loss of a character due to a hardware malfunction.

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnSlaveBusCharacterOverrunCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the remote device that it could not handle due to a character overrun condition, since its last restart, clear counters operation, or power-up. A character overrun is caused by data characters arriving at the port faster than they can be stored, or by the loss of a character due to a hardware malfunction.

class pymodbus.diag_message.ReturnIopOverrunCountRequest(data=0, **kwargs)

An IOP overrun is caused by data characters arriving at the port faster than they can be stored, or by the loss of a character due to a hardware malfunction. This function is specific to the 884.

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ReturnIopOverrunCountResponse(data=0, **kwargs)

The response data field returns the quantity of messages addressed to the slave that it could not handle due to an 884 IOP overrun condition, since its last restart, clear counters operation, or power-up.

class pymodbus.diag_message.ClearOverrunCountRequest(data=0, **kwargs)

Clears the overrun error counter and reset the error flag

An error flag should be cleared, but nothing else in the specification mentions is, so it is ignored.

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

class pymodbus.diag_message.ClearOverrunCountResponse(data=0, **kwargs)

Clears the overrun error counter and reset the error flag

class pymodbus.diag_message.GetClearModbusPlusRequest(**kwargs)

In addition to the Function code (08) and Subfunction code (00 15 hex) in the query, a two-byte Operation field is used to specify either a ‘Get Statistics’ or a ‘Clear Statistics’ operation. The two operations are exclusive - the ‘Get’ operation cannot clear the statistics, and the ‘Clear’ operation does not return statistics prior to clearing them. Statistics are also cleared on power-up of the slave device.

encode()

Base encoder for a diagnostic response we encode the data set in self.message

Returns:The encoded packet

execute(*args)

Execute the diagnostic request on the given device

Returns:The initialized response message

get_response_pdu_size()

Returns a series of 54 16-bit words (108 bytes) in the data field of the response (this function differs from the usual two-byte length of the data field). The data contains the statistics for the Modbus Plus peer processor in the slave device. Func_code (1 byte) + Sub function code (2 byte) + Operation (2 byte) + Data (108 bytes) :return:

class pymodbus.diag_message.GetClearModbusPlusResponse(data=0, **kwargs)

Returns a series of 54 16-bit words (108 bytes) in the data field of the response (this function differs from the usual two-byte length of the data field). The data contains the statistics for the Modbus Plus peer processor in the slave device.