Micrologix 1200 Ton preset resets to "0"

I have an application where we're using a Micrologix 1200, and there's a timer on that we use in our program where the preset value resets itself to "0". This is our third time this has happened. The previous two times I just set the preset back to 400 (0.01 time base).

Is there anyone out there that has ever seen or heard of this issue?

Thanks,

I havent seen that, but just put a Mov 400 timer.pre before the instruction.

Alrighty I'll try that, but would you happen to know why it would reset the preset for the timer by chance?

Sorry I misread your post, that you haven't seen that before.

The most common ways would be be a MOV or COP instruction overwriting the preset, or a HMI overwriting it.

Ahhh k, we do have an AB panelview 300 on the automation cell. This is the third time I've seen this issue in the last say four months, and we inherited this cell from our customer prolly over 7 years ago now. It is an older cell at least 15 years old I'd say.

The Panelview Standard can be set to "write to controller on power up". I believe this can be applied to all models (except RIO comms which do that by design). By default, when you create a new application, this box is checked in Panelbuilder32 software.

If this checkbox is ticked in the application that was downloaded to the PV300, then every time you cycle power to the HMI, it will write values from its application to the tags in the PLC. There are two choices, Terminal Presets (from the tag database) Last Terminal States.

In general, I turn this "feature" off...I have a story about an operator who almost got fired for making product out of spec due to a loose wire on a Panelview power connector.

OkiePC, I will have to look into the PV300 to see what its settings are set at. The only thing is that the power to panel view is not cycled that very often, pretty much the PV300 power stays on 24/7 for the cell, unless if something happens where we had to swap a component. Thanks for the response to my post.