Rockwell Automation Allen-Bradley 1747-SN

Publication 1747-UM013B-EN-P - January 2005
Specifications A-9
Adapter #1 (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 BT write/read modules in logical
rack 0
• one 2 word BT write/read module in logical rack 1
Adapter #2 (1771-ASB module):
• starting logical rack 2, logical group 0
• 2 logical groups (1/4 logical rack)
• one 64 word BT write/read module
Adapter #3 (1771-ASB module):
• starting logical rack 2, logical group 2
• 2 logical groups (1/4 logical rack)
• one 32 word BT write/read module
1. Use the throughput formula to calculate the maximum
throughput of the 1747-ASB module.
T
dm-bt
= 2T
ps
+ 2T
RIO
+ 2T
btx
+ T
adp
+ T
SNo-bt
+ T
SNi
+ T
id
+ T
od
T
ps
= 25.0 ms
T
RIO
= The total RIO scan time (ms)
T
btx
= Additional time due to sending any BT data on the RIO
link
T
adp
= Two 1747-ASB module backplane scan times (calculated
from ASB manual) = 2(4.5) = 9.0 ms
T
SNo-bt
= 22.0 ms from the table on page A-14, T
SNo
with
Block Transfers (Normal Mode). There are 3 logical racks
configured.
T
SNi
= 5.0 ms
T
id
= 10.0 ms, which is from I/O module instruction sheets
T
od
= 1.0 ms, which is from I/O module instruction sheets
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