Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 314)

Preface MicroLogix 1000 Programmable Controllers User Manual
B–26
Execution Time Worksheet
Use this worksheet to calculate your execution time for ladder program.
________
µ
s
_______
Procedure Maximum Scan Time
1. Input scan time, output scan time, housekeeping time, and forcing.
2. Estimate your program scan time:
A. Count the number of program rungs in your logic program and multiply by 6.
B. Add up your program execution times when all instructions are true. Include interrupt
routines in this calculation.
➀
3. Estimate your controller scan time:
A. Without communications, add sections 1 and 2
B. With communications, add sections 1 and 2 and multiply by 1.05
4. To determine your maximum scan time in ms, divide your controller scan time by 1000.
210
µ
s (discrete)
330
µ
s with forcing (analog)
250
µ
s without forcing (analog)
________
µ
s
________ ms
________
µ
s
________
➀
If a subroutine executes more than once per scan, include each subroutine execution scan time.