Rockwell Automation 1755-OF8 GuardPLC Controller Systems - Manual (Page 172)

172 Publication 1753-UM001C-EN-P - March 2010
Chapter 16 Peer-to-peer Communication Overview
Peer-to-Peer Profile IV: Medium & Noisy
The Medium and Noisy profile provides medium data throughput for
applications where only a moderate data update rate is required. It is
good for applications where the Worst Case ReactionTime is not a
critical factor. Minor loss of messages can be corrected.
Medium & Noisy Characteristics
Minimum Ethernet
network requirements
Medium or Fast
10 MBit (10 Base T) or 100 Mbit technology (100
Base TX) or network with both 10 MBit and 100
MBit components.
Usage of hubs possible.
Noisy
Low probability for loss of messages.
Time for
≥
1 repetitions.
Characteristics of the
communication path Moderate delays
ResponseTime
≤
ReceiveTMO
÷
2
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
Suitable HH network
profile Medium or Fast
Peer-to-Peer
parameter presets
•
QueueLen = 3
•
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