Module Scan Time - AB Quality ALLEN-BRADLEY 1791 User Manual

Module Scan Time

Block Transfer
Read
Input Sample
Rate
Block Transfer
Write
Output Update
1
Time depends on the remote I/O network configuration.
Scan time depends on the block transfer rate over the remote I/O network,
which is asynchronous to the module input sample rate and output update
rate. The block transfer rate is dependent on the controller, program length,
the amount of communication traffic to other modules on the remote I/O
network and the speed (baud rate) of the remote I/O network.
Figure 3.4
Module Scan Time Relationships
100ms to 2s
BTR1
108ms
Ch 0 Ch 1 Ch 2 Ch 3
100ms to 2s
BTW1
10ms
Ch 0 & Ch 1
updated
Chapter 3
Configuring Your Block I/O for PLC
Family Programmable Controllers
1
BTR2
Ch 0 Ch 1 Ch 2 Ch 3
1
BTW2
Ch 0 Ch 1
10ms
Ch 0 & Ch 1
updated
3-7