Rockwell Automation 1755-OF8 GuardPLC Controller Systems - Manual (Page 173)

Publication 1753-UM001C-EN-P - March 2010 173
Peer-to-peer Communication Overview Chapter 16
Peer-to-Peer Profile V: Slow & Cleanroom
This profile provides low data throughput for applications where only
a low data update rate is required from remote controllers, via
communication paths, whose conditions cannot be predicted by the
user.
Slow & Cleanroom Characteristics
TIP
Normally use the profile Slow & Noisy
(see page
174 ).
Minimum Ethernet
network
requirements
Slow
Primarily for data exchange via ISDN, leased
line or slow line-of-sight radio link.
Clean
No loss of data due to traffic overload, harsh
environmental conditions or network defects.
Time for
≥
0 repetitions.
Characteristics of the
communication path Moderate to long delays
ResponseTime
≤
ReceiveTMO, otherwise ERROR
Variables
ResponseTime manually set in the Peer-to-Peer Editor
ReceiveTMO manually set in the Peer-to-Peer Editor
WDZ manually set in the controller properties
N number of link partners a controller can talk to
defined in the Peer-to-Peer Editor
Suitable HH network
profile Medium or
Fast
Peer-to-Peer
parameter presets
•
QueueLen = 4
•
Communication Time Slice large enough to process and send
all data defined for transmission in one CPU cycle.
•
ResendTMO
– if ReceiveTMO
≥
2 x WDZ, then
ResendTMO = ResponseTime (
≥
0 Resends possible)
– if ReceiveTMO < 2 x WDZ, then
ResendTMO = ReceiveTMO
•
AckTMO = ReceiveTMO or AckTMO = AckTMOMax, whichever
is smaller
•
ProdRate = ResponseTime
ч
4