Rockwell Automation 1747-ASB Remote I/O Adapter - Manual (Page 138)

Publication 1747-UM006B-EN-P - June 2003
A-10 Specifications
words sent in the block transfer and the selected baud rate. RIO link
protocol allows for a maximum of one RIO block transfer to be sent to
each logical device on the RIO link during any single RIO scan. The
RIO scan increase (T
ri
) for each logical device is:
The total increase in the RIO scan time (T
btx
) is equal to:
T
btx
= sum of T
ri
for all logical devices
Discrete I/O Throughput with Block Transfers Present Example
A PLC 5/40 is controlling a 115.2K baud RIO link that has 3 adapters
and 4 logical devices.
1747-ASB module:
•
starting logical rack 0, logical group 0
•
12 logical groups (1 1/2 logical racks)
•
one 8 word and two 4 word block transfer write/read modules
in logical rack 0
•
one 2 word block transfer write/read module in logical rack 1
1771-ASB module:
•
starting logical rack 2, logical group 0
•
2 logical groups (1/4 logical racks)
•
one 64 word block transfer write/read module
1771-ASB module
•
starting logical rack 2, logical group 2
•
2 logical groups (1/4 logical racks)
•
one 64 word block transfer write/read module
Baud Rate RIO Scan Time Increase (T
ri
)
57.6K baud 0.300 x block transfer length + 5.0ms
115.2K baud 0.150 x block transfer length + 3.5ms
230.4K baud 0.075 x block transfer length + 2.0ms