Allen-Bradley 1747-SN User Manual page 158

You need to calculate your T
when the input closes on the 1746-IN16 until the output on the
1746-OB16 is on.
1. Use the throughput formula to calculate the maximum
throughput.
T = 2T + 2T
dm–nbt ps RIO
T = 25.0 ms, which is from the APS reference manual (assume for
ps
example)
T = The total RIO scan time (ms)
RIO
T = See value in the table on page A–13, T
SNo
Writes
(Normal Mode).
T = 5.0 ms
SNi
T = 10.0 ms, which is from I/O module instruction sheets
id
T = 1.0 ms, which is from I/O module instruction sheets
od
T = 2(25.0) + 2T
dm–nbt
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 numbers together:
T = T + T
RIO adapter 1 adapter 2
T = 1(4.0 ms) + 2(5.5 ms) + 3(3.5 ms)
RIO
T = 25.5 ms
RIO
3. Find T on page A–13 in the table T
SNo
Writes (Normal Mode). For this example T
are 4 logical racks configured. Therefore:
T = 7.0 ms
SNo
4. Substitute all the values for variables in the throughput formula
and solve for throughput:
T = 2T + 2T
dm–nbt ps RIO
T = 2(25.0)+ 2(25.5) + 8.0 + 7.0 + 5.0 + 10.0 + 1.0
dm–nbt
T = 132.0 ms = maximum throughput
dm–nbt
Specifications
: the RIO throughput time from
dm–nbt
+ T + T + T + T
adp SNo SNi id
+ 8.0 + T + 5.0 + 10.0 + 1.0
RIO SNo
). Locate the baud rate
RIO
+ T
adapter 3
without M0 File
SNo
+ 2T + T + T + T
bp SNo SNi
A–5
+ T
od
without M0 File
SNo
> T , and there
upd hold
+ T
id od
Publication 1747 6.6 - July 1996