At a Glance

This example covers implementation of a UNITE_SERVER function as an immediate server for a READ_VAR communication function. The Modbus link concerned is connected to the PCMCIA card of a TSX SCY 21601 module located in slot 2 of the base rack.

Programming

Programming in ST:

IF NOT %MW100:X0 THEN
   UNITE_SERVER(%MW100:2, %MW110:3, %MW10);
END_IF;

Request parameters:

Parameters

Description

%MW100:2

Management table

%MW110:3

Example: the immediate server is SCP114 configured as slave 49 in a SCY21601 (slot 4, rack 0).

  • Word 1: 16#FE00 corresponds to rack,

  • Word 2: 16#0405 corresponds to slot,

  • Word 3: 16#0095 correspond to channel.

See X-WAY addressing modes for details.

%MW10

Response:

  • Least significant byte: 16#03, UNITE read n words function received code.

  • Most significant byte: 16#03, UNITE read n words function response code.