User`s manual

GFK-1742A E-1

Local Logic Execution Time

This appendix contains information necessary to determine a local logic program’s execution time.

Local Logic Execution Timing Data

Local Logic program in the DSM is constrained to complete execution within

300 Microseconds

Exceeding the execution time limit will result in a watchdog timeout and an error being reported.

The watchdog timeout error will stop axes motion and Local Logic execution. The timing data

supplied in the tables below allows the programmer to compute the worst case execution time for a

program. Note that the data below represents

execution

times, not response times. For example, the

execution time required to write a value to the follower ratio variables is 0.30 microseconds,

however the time required to observe the resulting change in the axes motion would be in the order

of 2 to 5 milliseconds. Similarly for the digital inputs the hardware filter delays must be taken into

account when computing the response time.

Note:

If the program execution time is between 300

and 350 microseconds a watchdog timeout may not occur, depending on the task loading in the

module. The user should keep his program execution time within 300 microseconds to ensure that

it runs without any timeouts.

The tables below can be used to compute the worst case execution times and therefore

predetermine that a program will not cause a watchdog timeout. The examples below

illustrate the computation of execution times for a program.

Example 1

Appendix