Function Description
The XXMIT function block sends Modbus messages from a master PLC to multiple slave PLCs or sends ASCII character strings from the PLC's Modbus slave port number 1 to ASCII printers and terminals. XXMIT sends these messages over telephone dialup modems, radio modems, or simply direct connections.
NOTE: The XXMIT function block can only be used in
MAST task. There is an immediate fault code (127) if it is started
in the FAST / AUX or EVENT tasks (there is no control performed by Control Expert at build time).
NOTE: EN and ENO should NOT be used with the
XXMIT, otherwise the output parameters may
freeze. NOTE: Modbus communication through radio
modems with Quantum PLC is only possible with the XXMIT function block configured as Modbus
Master.
NOTE: Be careful that two masters (on the
same bus) do not send requests simultaneously otherwise the requests
are lost and each report will have a bad result which could be 16#0100
(request could not be processed) or 16#ODFF (slave is not present).
Software and Hardware Required
Software
XXMIT requires the following software:
PLC |
Operating System |
Unity Pro1/Control Expert |
|---|---|---|
Quantum |
2.3 or later |
2.3 or later |
Momentum |
1.0 or later |
8.0 or later |
1 Unity Pro is the former name of Control Expert for version 13.1 or earlier. |
||
Refer to Block availability on various hardware platforms for a list of supported hardware on the XXMIT function block.