Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 50)

I/O Communication
Chapter 3
3-2
Table 3.A
I/O Scan per I/O Chassis in Milliseconds
Number of Active I/O Channels
bps Chan 4 Config 1 2 3 4
57.6k Not DH/DH+
DH/DH+
7
8
7
8
7.5
9
8
N/A
115.2k Not DH/DH+
DH/DH+
4.5
5
5
6
5
7
6.5
N/A
230.4k Not DH/DH+
DH/DH+
3
N/A
3.5
N/A
5
N/A
6
N/A
Each I/O chassis that you add to the scanning sequence list (including
repeated I/O chassis in the list) increases the I/O scan time.
When you add block-transfer modules to the channel, the I/O scan time
increases by approximately 1ms per adapter on all channels while the
scanner executes the block-transfer instruction.
Calculating BlockĆTransfer Times
The time required to complete a block transfer depends on the number of:
I/O channels on the scanner that contain block-transfer I/O modules
active I/O channels on the scanner
entries in the I/O chassis scanning sequence list for the channel
block-transfer I/O modules on the channel
To calculate the time required for the scanner to execute all block transfers
on the channel and be ready to execute the block-transfer again:
1. Determine the number of active I/O channels on the scanner.
2. Determine the number of I/O channels with block-transfer
I/O modules.
3. Determine the nominal block-transfer time (see Table 3.B).