Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 174)

Publication 1747-UM010B-EN-P - September 2003
A-10 Specifications
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, which is from the APS reference manual (assume
for example)
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 B-13, TSNo 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
T
dm-bt
= 2(25.0) + 2T
RIO
+ 2T
btx
+ 9.0 + 22.0 + 5.0 + 10.0 + 1.0
2. Calculate the total RIO scan time (T
RIO
). Locate the baud rate
(115.2K) and adapter size which is found in the table on page
B-4. Multiply the RIO scan times listed under the 115.2K
heading by the number of each different type of rack that you
have. Add those number together.
T
RIO
= Tadapter1 + Tadapter2 + Tadapter3
T
RIO
= 1(5.5) + 1(4.0) + 2(3.5)
T
RIO
= 16.5 ms