Rockwell Automation 1791-XXXX ANALOG BLOCK I/O - Manual (Page 40)

Configuring Your Block I/O for PLC
Family Programmable Controllers
Chapter 3
3-7
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
Ch 0 Ch 1 Ch 2 Ch 3 Ch 0 Ch 1 Ch 2 Ch 3 Ch 0 Ch 1
100ms to 2s 1
Ch 0 & Ch 1
updated
BTW1 BTW2
Block Transfer
Read
Block Transfer
Write
Input Sample
Rate
Output Update
100ms to 2s 1
BTR1 BTR2
Ch 0 & Ch 1
updated
10ms 10ms
108ms
1 Time depends on the remote I/O network configuration.
Module Scan Time