file_message — File Modbus Messages

Module author: Galen Collins <>

Section author: Galen Collins <>

API Documentation

File Record Read/Write Messages

Currently none of these messages are implemented

class pymodbus.file_message.ReadFifoQueueRequest(address)

This function code allows to read the contents of a First-In-First-Out (FIFO) queue of register in a remote device. The function returns a count of the registers in the queue, followed by the queued data. Up to 32 registers can be read: the count, plus up to 31 queued data registers.

The queue count register is returned first, followed by the queued data registers. The function reads the queue contents, but does not clear them.


Decodes the incoming request

Parameters:data – The data to decode into the address

Encodes the request packet

Returns:The byte encoded packet

Run a read exeception status request against the store

Parameters:context – The datastore to request from
Returns:The populated response
class pymodbus.file_message.ReadFifoQueueResponse(values)

In a normal response, the byte count shows the quantity of bytes to follow, including the queue count bytes and value register bytes (but not including the error check field). The queue count is the quantity of data registers in the queue (not including the count register).

If the queue count exceeds 31, an exception response is returned with an error code of 03 (Illegal Data Value).


Decodes a the response

Parameters:data – The packet data to decode

Encodes the response

Returns:The byte encoded message

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