Estimate throughput – Rockwell Automation Logix5000 Controllers Tasks, Programs, and Routines Programming Manual User Manual

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Manage event tasks Chapter 2

The event task uses the following logic to control the diverter.

If Diverter_Photoeye = 1 (part is in the diverter position)
and Divert_Part = 1 (divert this part)

then Diverter = 1 (turn on the diverter)

otherwise Diverter = 0 (turn off the diverter)

Immediately send the output values to the output module in slot 5.

Estimate throughput

To estimate the throughput time from input to output (screw to screw), use the

following worksheet.

Consideration

Value

1.

What is the input filter time of the module that triggers the event task?

µs

This is typically shown in milliseconds. Convert it to microseconds (µs).

2.

What is the hardware response time for the input module that triggers the event task?

µs

Make sure you use the appropriate type of transition (Off → On or On → Off). See Nominal hardware response times for
the 1756 I/O modules most commonly used with Event tasks later in this section.

3.

What is the backplane communication time?

µs

If chassis size is

Use this value (worst case)

4 slot

13 µs

7 slot

22 µs

10 slot

32 µs

13 slot

42 µs

17 slot

54 µs

4.

What is the total execution time of the programs of the event task?

µs

5.

What is the backplane communication time? (Same value as step 3.)

µs

6.

What is the hardware response time of the output module.

µs

7.

Add steps 1...6. This is the minimum estimated throughput, where execution of the motion planner or other tasks do not delay or interrupt the

event task.

µs

8.

What is the scan time of the motion group?

µs

9.

What is the total scan time of the tasks that have a higher priority than this event task (if any)?

µs

10.

Add steps 7...9. This is the nominal estimated throughput, where execution of the motion planner or other tasks delay or interrupt the event task.

µs

Rockwell Automation Publication 1756-PM005-EN-P - October 2014

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