Msg_Modbus - Allen-Bradley Micro800 General Instructions Manual

MSG_MODBUS

Parameter
IN
Cancel
LocalCfg
TargetCfg
LocalAddr
Q
Error
ErrorID
MSG_MODBUS sends a Modbus message over a serial port.
MSG_MODBUS operation
A maximum of four message requests per channel can be processed in one scan.
For Ladder Diagram programs, message requests are executed at the end of a
ladder scan.
Arguments
Parameter Data type
type
Input BOOL
Input BOOL
Input MODBUSLOCPARA
Input MODBUSTARPARA
Input MODBUSLOCADDR
Output BOOL
Output BOOL
Output UINT
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015
Communication instructions
Description
If Rising Edge (IN turns from FALSE to TRUE), start the function block with the
precondition that the last operation has been completed.
TRUE - Cancel the execution of the function block.
Define structure input (local device).
Defines the input structure for the local device.
See MODBUSLOCPARA data type on page
Define structure input (target device).
Defines the input structure for the target device.
See MODBUSTARPARA data type on page
MODBUSLOCADDR is a 125 Word array that is used by Read commands to store
the data (1-125 words) returned by the Modbus slave and by Write commands
to buffer the data (1-125 words) to be sent to the Modbus slave.
Outputs of this instruction are updated asynchronously from the program scan.
Output Q cannot be used to re-trigger the instruction since IN is edge
triggered.TRUE - MSG instruction is finished.
FALSE - MSG instruction is not finished.
TRUE - When error occurs.
FALSE - No error.
Show the error code when message transfer failed.
See Modbus error codes on page 199.
Chapter 9
199.
204.
197