Rockwell Automation 1440-RMA00-04RC XM-440 Master Relay Module - Manual (Page 44)

Rockwell Automation Publication GMSI10-UM009D-EN-P - June 2011
44 Configuration Parameters
Slave EPR Sets the rate at which the packets will be expected
to be received by the XM-440.
When the XM-440 opens a polled I/O connection, it
sets a maximum timeout (Expected Packet Rate
(EPR)) with the slave. If the slave does not receive a
packet from the XM-440 within 4 times the EPR
value, the slave drops the connection. If the XM-440
does not receive a packet from the slave within 4
times the EPR value, it drops the connection and
periodically attempts to open a new connection.
Enter a value from 10 to 32,000
milliseconds. The default is 200
milliseconds.
Note:
• Increase the Slave EPR if you are
experiencing timeouts and your
scanlist is longer than typical. If the
Slave EPR value is much less than
the XM-440 total scan period, the
XM-440 and/or slave devices may
timeout because the XM-440 is not
hearing from the slaves within the 4
times the EPR. The total scan period
increases with the number of
modules in the scanlist, the amount
of competing network traffic, and
the interscan delay.
• Decrease the Slave EPR if it takes
too long for the XM-440 to detect a
missing device and your total scan
period is shorter than typical.
Important: Changing the EPR value
should be done carefully.
XM Network Node List Parameters
Parameter Name Description Values/Comments