Allen-Bradley 1747-SN User Manual page 162

2. Calculate the total RIO scan time (T
(115.2K) and adapter size which is found in the table on page
A–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 = Tadapter1 + Tadapter2 + Tadapter3
RIO
T = 1(5.5) + 1(4.0) + 2(3.5)
RIO
T = 16.5 ms
RIO
3. Calculate the maximum T
determining the largest BT that will occur to any device within a
logical rack and calculating the transfer time using the table on
page A–7. Then add together the T
to obtain T .
btx
T for rack 0 = 0.150(8) + 3.5 = 4.7 ms (maximum BT to rack 0 is 8
ri
words)
T for rack 1 = 0.150(2) + 3.5 = 3.8 ms (maximum BT to rack 1 is 2
ri
words)
T for rack 2 = 0.150(64) + 3.5 = 13.1 ms (maximum BT to rack 2 is 64
ri
words)
T = T + T + T
btx ri0 ri1 ri2
4. Substitute all the values for variables in the throughput formula
and solve for throughput.
T = 2(25.0) + 2(16.5) + 2(21.6) + 9.0 + 22.0 + 5.0 + 10.0 + 1.0
dm–bt
T = 173.2 ms = maximum throughput
dm–bt
Specifications
). Locate the baud rate
RIO
time for each logical rack. Do this by
ri
times for each logical rack
ri
= 4.7 + 3.8 + 13.1 = 21.6 ms
A–9
Publication 1747 6.6 - July 1996