Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 109)

Publication AG-UM008C-EN-P - February 2005
Configuring MicroLogix 1100/1200/1500 Controllers 3-41
Message Timeout value should be at least (Slave Channel Poll
Timeout) * (Slave channel Message Retries + 1), rounded up to the
next whole second.
Minimum Radio Modem MSG Block Message Timeout
The minimum radio modem MSG Block Message Timeout should
allow for the end-to-end transmission of the command going out and
the reply coming back over the radio modem network, including time
through repeaters and/or store and forward nodes.
Minimum Point-to-Point MSG Block Message Timeout
The minimum point-to-point MSG Block Message Timeout should
allow for the processor to go through Message Retries plus one ACK
time out. Therefore, the minimum MSG Block Message Timeout value
should be at least (ACK Timeout) * (Channel Message Retries + 1),
rounded up to the next whole second.
TIP
Leave the Message Retries at default (3) unless you
have an extremely error free or extremely error
prone network.
Minimum Slave MSG Block
Message Timeout
= (Slave channel Poll Timeout)*(Slave Channel Message Retries + 1)
TIP
The default MSG Block Message Timeout is 5
seconds but for most radio modem configurations,
this can be reduced to 2 seconds.
TIP
Leave the channel Message Retries at default (3)
unless you have an extremely error free or extremely
error prone network.
Minimum Point-to-Point MSG Block
Message Timeout
= (ACK Timeout)*(Channel Message Retries + 1)