84
Explicit Messages
Appendix C
C-3
Using Explicit Messages
The following example shows how to use explicit messages with a PROFIBUS Communication Unit connected
to a CJ1W-PRM21 Profibus Master Unit.
Example: Sending a “Unit Maintenance Present Value Read” command to the
PROFIBUS Communication Unit
.
Example: PROFIBUS Master Unit’s station address: 05
Unit number: 0
Unit address: 11 Hex
GRT1-PRT Communication Unit’s station address: 65
Operation
Reads the Alarm data of the connected SmartSlice I/O Unit from the PROFIBUS Communication Unit.
The data is read using the EXPLICIT MESSAGE SEND command (2801).
The command data is written in words starting from D01000 in the PLC and the response data is stored in
words starting from D02000.
If the command does not end normally, the end code is stored in D00006 and the send command is re-exe-
cuted.
Note
The maximum length of the EXPLICIT MESSAGE SEND command (2801) when used for sending data
over PROFIBUS is limited to 1004 bytes.
CMND
C
S
D
PROFIBUS DP-V1 Master Unit
Ladder program
Explicit message
sent
PROFIBUS
Network
Read SmartSlice
alarm data
SmartSlice I/O System
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