device — Modbus Device Representation

API Documentation

Modbus Device Controller

These are the device management handlers. They should be maintained in the server context and the various methods should be inserted in the correct locations.

class pymodbus.device.ModbusAccessControl

This is a simple implementation of a Network Management System table. Its purpose is to control access to the server (if it is used). We assume that if an entry is in the table, it is allowed accesses to resources. However, if the host does not appear in the table (all unknown hosts) its connection will simply be closed.

Since it is a singleton, only one version can possible exist and all instances pull from here.

__contains__(host)

Check if a host is allowed to access resources

Parameters:host – The host to check
__iter__()

Iterater over the network access table

Returns:An iterator of the network access table
add(host)

Add allowed host(s) from the NMS table

Parameters:host – The host to add
check(host)

Check if a host is allowed to access resources

Parameters:host – The host to check
remove(host)

Remove allowed host(s) from the NMS table

Parameters:host – The host to remove
class pymodbus.device.ModbusPlusStatistics

This is used to maintain the current modbus plus statistics count. As of right now this is simply a stub to complete the modbus implementation. For more information, see the modbus implementation guide page 87.

__init__()

Initialize the modbus plus statistics with the default information.

__iter__()

Iterater over the statistics

Returns:An iterator of the modbus plus statistics
encode()

Returns a summary of the modbus plus statistics

Returns:54 16-bit words representing the status
reset()

This clears all of the modbus plus statistics

summary()

Returns a summary of the modbus plus statistics

Returns:54 16-bit words representing the status
class pymodbus.device.ModbusDeviceIdentification(info=None)

This is used to supply the device identification for the readDeviceIdentification function

For more information read section 6.21 of the modbus application protocol.

__getitem__(key)

Wrapper used to access the device information

Parameters:key – The register to read
__init__(info=None)

Initialize the datastore with the elements you need. (note acceptable range is [0x00-0x06,0x80-0xFF] inclusive)

Parameters:information – A dictionary of {int:string} of values
__iter__()

Iterater over the device information

Returns:An iterator of the device information
__setitem__(key, value)

Wrapper used to access the device information

Parameters:
  • key – The register to set
  • value – The new value for referenced register
__str__()

Build a representation of the device

Returns:A string representation of the device
summary()

Return a summary of the main items

Returns:An dictionary of the main items
update(value)

Update the values of this identity using another identify as the value

Parameters:value – The value to copy values from
class pymodbus.device.DeviceInformationFactory

This is a helper factory that really just hides some of the complexity of processing the device information requests (function code 0x2b 0x0e).

classmethod _DeviceInformationFactory__get(identity, object_id)

Read a single object_id from the device information

Parameters:
  • identity – The identity block to pull data from
  • object_id – The specific object id to read
Returns:

The requested data (id, length, value)
classmethod _DeviceInformationFactory__gets(identity, object_ids)

Read multiple object_ids from the device information

Parameters:
  • identity – The identity block to pull data from
  • object_ids – The specific object ids to read
Returns:

The requested data (id, length, value)
classmethod get(control, read_code=1, object_id=0)

Get the requested device data from the system

Parameters:
  • control – The control block to pull data from
  • read_code – The read code to process
  • object_id – The specific object_id to read
Returns:

The requested data (id, length, value)
class pymodbus.device.ModbusControlBlock

This is a global singleotn that controls all system information

All activity should be logged here and all diagnostic requests should come from here.

__iter__()

Iterater over the device counters

Returns:An iterator of the device counters
__str__()

Build a representation of the control block

Returns:A string representation of the control block
_setDelimiter(char)

This changes the serial delimiter character

Parameters:char – The new serial delimiter character
_setListenOnly(value)

This toggles the listen only status

Parameters:value – The value to set the listen status to
_setMode(mode)

This toggles the current serial mode

Parameters:mode – The data transfer method in (RTU, ASCII)
addEvent(event)

Adds a new event to the event log

Parameters:event – A new event to add to the log
clearEvents()

Clears the current list of events

getDiagnostic(bit)

This gets the value in the diagnostic register

Parameters:bit – The bit to get
Returns:The current value of the requested bit
getDiagnosticRegister()

This gets the entire diagnostic register

Returns:The diagnostic register collection
getEvents()

Returns an encoded collection of the event log.

Returns:The encoded events packet
reset()

This clears all of the system counters and the diagnostic register

setDiagnostic(mapping)

This sets the value in the diagnostic register

Parameters:mapping – Dictionary of key:value pairs to set