User guide

Instructions
Chapter 18
I/O Message and Communication
18–11
Example 2 – Program File 2 of SLC 5/02 Processor
(U)
B3
0
(EN)
(DN)
(ER)
MSG
READ/WRITE MESSAGE
Read/write WRITE
Target Device 500CPU
Control Block N10:0
Control Block Length 7
END
0
2
* MSG instruction
status bits:
13 = DN
15 = EN
]/[
N7:0
0
(L)
B3
0
( )
N7:0
1
(RES)
T4:0
(EN)
(DN)
TON
TIMER ON DELAY
Timer T4:0
Time Base 0.01
Preset 400
Accum 0
Temperature–sensing
Input Device
] [
S:1
15
] [
S:4
6
3
] [
B3
0
(L)
N7:0
0
] [
S:1
15
] [
I:1.0
5
(EN)
(DN)
(ER)
MSG
READ/WRITE MESSAGE
Read/write READ
Target Device 500CPU
Control Block N11:0
Control Block Length 7
] [
N10:0
13*
] [
T4:0
DN
] [
N11:0
13*
(U)
B3
0
(RES)
T4:0
(L)
N7:0
0
(U)
N11:0
15*
(U)
N10:0
15*
Operation notes appear on the following page.
4
5
6
7
Bit 1 of the message
word. Used for fan
control.
Bit 0 of the message
word. This is the
interlock bit.
4–second Timer
Write message instruction.
The source and target file
addresses are N7:0
Target node: 3
Message length: 1 word.
Read message instruction.
The destination and target
file addresses are N7:0
Target node: 3
Message length: 1 word.
Latch – This alarm
instruction notifies the
application if the interlock
bit N7:0/0 remains set for
more than 4 seconds.
First Pass Bit
First Pass Bit
1280 ms Clock Bit
Message Write Done
Bit
Message Read Done
Bit
1
(L)
B3
10