Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 59)

I/O Communication
Chapter 3
3-11
To calculate the time needed to update a specific input file on the
peer-to-peer or backup communication link, use the following procedure:
1. Determine the number of words in the output file being sent to this
specific input file. Divide by 8 and round up.
2. Determine the total number of slaves on the link.
3. Determine the greatest number of active channels on any scanner on
the peer-to-peer communication link.
4. Find the nominal peer-to-peer time by using Table 3.C and the result
of step 2.
5. Multiply the results of steps 1, 2 and 4.
Update time = (Nominal time) x (output words/8) x
(number of slaves)
Figure 3.8 shows an example of 3 PLC-3 controllers using peer-to-peer
communication to communicate with each other on one channel and with
other PLC-3 controllers on other channels. For this example, assume that
each output file has 200 words.