Rockwell Automation 1756-L55M12, Руководство по выбору

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56
1756-SG001G-EN-P — March 2004
Estimating event task throughput
To estimate the throughput time from input to output (screw to screw), use the
following worksheet:
Use the following table to determine the nominal hardware response time for
selected 1756 I/O modules.
Consideration: Value (in
µµ
s):
1.
What is the input filter time of the module that triggers the event task?
This is typically shown in milliseconds, Convert it to microseconds (
µ
s).
2. What is the hardware response time for the input module that triggers the event task?
Make sure you use the appropriate type of transition (Off to On or On to Off). See the following table.
3. What is the backplane communication time?
If the chassis size is: Use this value (worst case):
4 slot 13
µ
s
7 slot 22
µ
s
10 slot 32
µ
s
13 slot 42
µ
s
17 slot 54
µ
s
4. What is the total execution time of the programs in the event task?
5. What is the backplane communication time (same value as step 3).
6. What is the hardware response time of the output module?
7.
Add steps 1 through 6. This is the minimum estimated throughput, where execution of the motion planner or
other tasks do
not
delay or interrupt the event task.
8. What is the scan time of the motion group?
9. What is the total scan time of the tasks that have a higher priority than this event task (if any)?
10. Add steps 7 through 9. This is the nominal estimated throughput, where execution of the motion planner or
other tasks delay or interrupt the event task.
Module:
1756-IB16
1756-IB16D
1756-IB32
1756-IV16
1756-IV32
1756-OB16D
1756-OB16E
1756-OB32
1756-OV16E
1756-OV32E
Nominal reponse time
µµ
s:
25° C
Off to On
265
303
330
257
381
48
60
38
67
65
On to Off
582
613
359
435
476
519
290
160
260
174
60° C
Off to On
265
305
345
254
319
51
61
49
65
66
On to Off
638
673
378
489
536
573
324
179
326
210