Publication 1766-RM001A-EN-P - October 2008
Communications Instructions
399
The Message Element
The MSG instruction built into the controller uses a MG data file to
process the message instruction. The MG data file, shown at left, is
accessed using the MG prefix. Each message instruction utilizes an
element within a MG data file. For example, MG11:0 is the first element in
message data file 11.
Message File Sub-Elements
Each MSG instruction must use a unique Element in a MSG File. The MSG
element for each MSG instruction holds all of the parameters and status
information for that particular MSG instruction.
Each MSG File Element consists of Sub-Elements 0…24 as shown in the
following table.
Message File Elements
Sub-
Element
Name
Description
Paramet
er
Size
User Program
Access
(2)
0 to 1
Reserved
Word
read only
2
Messaging Type: 0 (for PCCC), 1 (for CIP), 2 (for Modbus Master)
Word
read only
3
for PCCC Messaging: bits 07-00 (CMD code), bits 15-08 (FNC code)
for CIP: bits 07-00 (Service Code), bits 15-08 (Supplemental Object
Path Data Count)
for Modbus Master: bits 07-00 (Function Code), bits 15-08 (Reserved)
derived
Word
read only
4
Internal Physical Address
Word
read only
5
MG11:0.RBL
PCCC: Remote Bridge Link ID
Modbus Master: not used
Y
Word
read only
6
MG11:0.LBN
PCCC: Local Bridge Node Address
Modbus Master: not used
Y
Word
read only
7
MG11:0.RBN
PCCC: Remote Bridge Node Address
Modbus Master: not used
Y
Word
read only
8
MG11:0.CHN
Channel: bits 07-00 (0 for Channel 0,1 for Channel 1)
Slot: bits 15-08 (Not used)
Y
Word
read/write
9
MG11:0.NOD Target Node Number
Y
Word
read/write
10
MG11:0.MTO Message timeout setting or preset in seconds
Y
Word
read/write
11
PCCC: Number of bytes to read/write
Modbus Master: Number of Modbus elements to read/write
Word
read only
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