Compact logix odd integer behavior

[rwraley 1]

Question, we have several compact logix processors with no nonvolitale storage. When the units are powered down some retain integer values that were written from the OIT to Int[50] before power down and yet others revert back to the original programmed value default, which is what I would expect to happen. The logic uses an up pushbutton on the OIT to one shot an ADD 1 to the integer and a down pushbutton to one shot a subtract 1 to the integer to increment this positioner valve from 1 to 100%. The original default in the program is 24. Some go back to 24 after power cycle and some stay at 55 or what ever the last value was before power cycle. Can anyone explain if I have no non-volatile memory to write from on power up how this can occur? Thanks.

[METSYSTEM 1]

How long do you power down for? Is it possible there is a capacitance charge holding memory? I'm no expert but it sounds like hardware electronics rather than code issues.

[b_carlton 61]

Since you are concerned about values which can be changed by the OIT you may wish to look at their setup. Some OIT's keep a record of the last change and download it at start up, some keep a default and do the same and others do no writing at all on start up. Edited 15 Sep 2011 by b_carlton