task execution time for micrologix 1500 LRP Series C

[satheesh k gannoju 0]

HI i am using Micrologix 1500 LRP 1764 28BXB. i want to know what is the exexcution time taken by this PLC when my program is downloaded and running. can any one help how to get that time? Scantimes is given when u go through Processor Status but that time is multiple of 100 or what? i want to use timer can any one help how to start and stop timer and get time difference in Accumulator ? Pleas can anyone help in this issue? Thanks & Regards Satheesh.G

[BobLfoot 302]

The scantime for MLGX is usually in microseconds. Remember this is only the program scan time, not I/O Overhead, Messaging Overhead and so forth. You might sample the free running timer at the start and end of a program or at the same rung each scan. This assumes your scan is long enough for it to change. The Ab Library webpage has the instruction ref and can give you time consumed by each instruction down to the .01 microseconds. It woould help to know why scan time is critical to suggest other options?

[paulengr 44]

Downloading and running (and online programming) and generally anything that requires communication also affects scan time. So the act of trying to measure scan times can in fact change them.