LG GLOFA-GM Series User Manual page 277

Chapter 8 Exercising program
2) Communication protocol
Communication protocol to communicate with MJ71UC24 computer link module is as follows.
[Figure 8.13] TX sequence of TX/RX frames
If GLOFA Cnet sends A) Read request frame first, MJ71UC24, to respond to this, reads data of applicable area
to transmit B) Response data frame, and Cnet I/F module sends C) Immediately Response frame to inform
MJ71UC24 of data received. Next is TX/RX frame structure.
A) Read request frame(Cnets' request : Read request of 12 words in D0100 of station 1)
Classification
Frame
B) Response format to total Read (Response of MJ71UC24 side)
Classification
Frame
C) Immediate response
Classification
Frame
Next is for communication frame contents. Refer to the user's manual of GOLDSEC-M computer link unit for
more information.
Station No. : Station No.(station 1) of MJ71UC24
PLC No. : Set to FF
Command : WR (Total Read command of word unit in device memory)
A) Read request frame
C) Immediate response frame
Station
Header PLC No.
No.
ENQ 01 FF
Station
Header PLC No.
No.
STX 01
Header
ACK
B) Response data
Message
Command
wait
WR 0
FF Data (12 words) of D0100 address
Station No.
01
8-26
Number of
Head device
D0100
Data
PLC No.
FF
device
0C
Tail
ETX