Rockwell Automation 1755-OF8 GuardPLC Controller Systems - Manual (Page 174)

174 Publication 1753-UM001C-EN-P - March 2010
Chapter 16 Peer-to-peer Communication Overview
Peer-to-Peer Profile IV: Slow & Noisy
This profile provides low data throughput for applications where only
low data update rates are required. It is primarily for data exchange
via poor quality telephone lines or distorted radio links.
Slow & Noisy Characteristics
Minimum Ethernet
network requirements
Slow
Data transfer via telephone, satellite link, radio,
and so forth.
Noisy
Low loss of data due to distortions on the
communication path or network defects.
Time for
≥
1 repetitions.
Characteristics of the
communication path Moderate to long delays
ResponseTime
≤
ReceiveTMO
÷
2, otherwise ERROR
Variables
ResponseTime manually set in the Peer-to-Peer Editor
ReceiveTMO manually set 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 (
≥
1 Resend possible)
– if ReceiveTMO < 2 x WDZ, then ERROR
•
AckTMO = ReceiveTMO or AckTMO = AckTMOMax, whichever
is smaller
•
ProdRate = ResponseTime
ч
4