Installation manual

Publication 1747-RM001G-EN-P - November 2008
12-8 SLC Communication Instructions
You can use the timeout control similar to the SLC 5/02 MSG instruction or
use the built in timeout control (recommended). If the timeout value is set to
0, the functionality is similar to the SLC 5/02 MSG instruction. It differs in
that once the TO bit is set, it will be reset automatically along with the ER bit
on the next MSG rung false-to-true transition. We highly recommend setting
the internal timeout value to something other than zero.
Figure 12.3 SLC 5/03, SLC 5/04, and SLC 5/05 Non-repeating
TIP
If you consistently enable more MSG instructions than the
buffers and queues can accommodate, the order in which
MSG instructions enter the queue is determined by the
order in which they are scanned. This means MSG
instructions closest to the beginning of the program enter
the queue regularly and MSG instructions later in the
program may not ever enter the queue.
0000
0000
B3:0
B3:0
0
MSG_TRIGGER
MSG_TRIGGER
EN
EN
DN
DN
ER
ER
MSG
MSG
Read/Write Message
Read/Write Message
Type
Type
Peer-To-Peer
Peer-To-Peer
Read/Write
Read/Write
Read
Read
Target Device
Target Device
500CPU
500CPU
Local/Remote
Local/Remote
Local
Local
Control Block
Control Block
N9:0
N9:0
Control Block Length
Control Block Length
14
14
Setup Screen
Setup Screen
SLC_503_504_505_MSG
SLC_503_504_505_MSG
0001
0001
N9:0
N9:0
13
13
MSG_DN_BIT
MSG_DN_BIT
N9:0
N9:0
12
12
MSG_ER_BIT
MSG_ER_BIT
U
B3:0
B3:0
0
MSG_TRIGGER
MSG_TRIGGER
0002
0002
END
END