Rockwell Automation T8017 Trusted Peer to Peer Communications - Manual (Page 43)

Trusted
TM
Communication Software Package T8017
Issue 10 Mar 08 PD-T8017 43
2.6. Suggested Configuration
The Peer to Peer I/O board definitions for timeout parameters should be set appropriate to the peer
system as described below.
Equipment Parameter Description
dxpnc40
RESPONSE_TMO 0ms is recommended on a local network.
REFRESH_TMO (Npeer x TX_DATA_TMO)
Master TX_DATA_TMO Set to RESPONSE_TMO or 2mS, which ever is greater, multiplied by the maximum
number of (dxpao + dxpdo) output boards in any single controller + 16ms.
dxpdi & dxpai
Input REFRESH_TMO Set to the longest acceptable time before stale data should cause a trip. (this time is
used as Input REFRESH_TMO below)
dxpdo &
dxpao
Output REFRESH_TMO (Input REFRESH_TMO) - ((Npeer x TX_DATA_TMO) + TSsource + TSdest + 50ms)
2
Table 22 Peer to Peer I/O Board definitions for Timeouts Parameters
Where: -
Npeer = number of peer to peer controllers
TSsource = Maximum application scan time of controller with output board
TSdest = Maximum application scan time of controller with input board
Note that if the Output REFRESH_TMO calculation results in a negative number, then the Peer to Peer
network is too complex for the Process Safety Time.