Time management in control logix

[Hisma 2]

Just wondering what is the best method for recording an accurate sequence of events in control logix. I do not believe that CLX time-stamps events locally, does it? My company has been given a HistorianME module to test out, by our rockwell reps. It seems like a very capable device, and I got it successfully communicating with a CLX processor and Pi server. I have not done much testing with it however. My questions are: 1. To get accurate alarm/status SOE, do I need to poll my digital tags at high speed so events get recorded as fast as the PLC can process it? Or can I poll at a slower speed (say 1 second), and controller-level time-stamping will ensure we have accurate SOE? 2. How do most of you out there handle your event recording? To those of you where sequence of events is absolutely critical, what method do you employ to get maximum accuracy on time-stamps and event sequence?

[Gerry 13]

It depends on what resolution you require -- if a periodic task will catch all expected rapid sequences without detriment to overall processor function, do that. For special needs, there is a special SOE input module 1756-IB16ISOE.