Rockwell Automation 1747-SN Remote I/O Scanner - Manual (Page 105)

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.
Tdm-bt = 2Tps + 2TRIO + 2Tbtx + Tadp + TSNo-bt + TSNi + Tid
+ Tod
Tps = 25.0 ms
TRIO = The total RIO scan time (ms)
Tbtx = Additional time due to sending any BT data on the RIO
link
Tadp = Two 1747-ASB module backplane scan times (calculated
from ASB manual) = 2(4.5) = 9.0 ms
TSNo-bt = 22.0 ms from the table on page A-14, TSNo with
Block Transfers (Normal Mode). There are 3 logical racks
configured.
TSNi = 5.0 ms
Tid = 10.0 ms, which is from I/O module instruction sheets
Tod = 1.0 ms, which is from I/O module instruction sheets