Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 User Manual
Page 58
I/O Communication
Chapter 3
3-10
Calculating PeerĆtoĆPeer and Backup Communication Times
The time required to transfer a file across a peer-to-peer or backup
communication link depends on the number of:
active channels on the scanner
communication
rate
words in the output files
To calculate the time needed to update every input file on the link, use the
following procedure:
1.
Determine the number of words in all output files of the master and
each slave on the peer-to-peer communication link. Add them, divide
by 16, and round up to the nearest whole number.
Important: Remember that the master has an output file for
each slave.
2.
Determine the greatest number of active channels on any scanner on
the peer-to-peer communication channel.
3.
Find the nominal peer-to-peer time by using Table 3.C and the result
of step 2.
Table 3.C
PeerĆtoĆPeer and Backup Communication Times per Slave
in Milliseconds
Number of Active I/O Channels
bps
Chan 4 Config
1
2
3
4
57.6k
Not DH/DH+
DH/DH+
12
12.5
12
14
12.5
14
13
N/A
115.2k
Not DH/DH+
DH/DH+
8
9
8.5
10
9
11
10.5
N/A
230.4k
Not DH/DH+
DH/DH+
6.5
N/A
7
N/A
8
N/A
9
N/A
4.
Multiply the result of step 3 by the result of step 1.
Update Time = (Nominal time) x (total words/16)