What can cause the timing of a program to change?

[JohnKuch]

I have currently written several programs using LabView 7. In these programs I have loops that are written to read data for 10sec(200ms wait 50 loop iterations). I have run and tested these many times with no problems. When I used these programs on the same computer, but in a different facility the timing was completely different. Instead of running for 10 secs. the program ran nearly 50 sec.

Any ideas?

[srm@viewpointusa.com]

If there was no change in other explicit programs that were running on the computer, look to anti-virus and network differences. moving to another network might cause the differences you are seeing. If you are communicating with different equipment, there may be different settings causing your loops to exceed your time limit

[djs_at_eaton]

I've seen speed issues related to OS and processor changes because disk access and processor speed make things happen faster. Timing of signals to the test article gets either faster or slower as a result. Tests that used to pass now fail. Sometimes adding more delay helps. We had one situation where a new OS on an older machine bogged so badly that almost nothing would run. Changing the processor fixed that, but made some program transitions too fast.

That particular program used server calls that dynamically loaded VIs from the disk. The new processor and disk were both faster, but the processor was maybe 5x faster while the disk was only 2x faster. The processor called the disk to write a file, the next call was to print the file using EXCEL. The
call to print arrived at the disk before it finished writing the file. Fixed with a slight delay.