Retentive timers

I am posting to pick your brains. I am trying to create an automated maintenace notification system for equipment. The one obstacle I think I am going to run into is loading from the EEPROM upon corrupt memory. All registers would lose their values (i.e. machine run hours which would be used to control the maintenance notification).

Is there some advanced features that can be utilized to store information (register values) to non volitle memory of some kind and then reload the values after a corrupt memory EEPROM load?

Specifically in CLX processors.

Thanks in advance

I don't know about CLX processors. For PLC's in general, I would think you need a Coprocessor module to do something like that.

Upon corrupt memory?
What do you mean?

Upon corrupt memory is a setting that is selected during the EEPROM Loading process.


You have 3 options, upon corrupt memory, on power-up and user initiated.

Upon corrupt memory is most commonly used, i.e. processor losses power for a long period of time and the backup battery fails. The memory is then erased and this would constitute to load from the EEPROM.

It doesn't help with the memory problem, but for your application look at using the TOT instruction instead of RTO.

Fix the tagname.In value at 1.0 instead of connecting it to another tag. Fix the gain at 1.0 and set tagname.timebase to 2. This configures the TOT to totalize time in units of hours. Setting tagname.timebase to 3 configures it to totalize days.
Use the tagname.EN bit to start/stop time totalizing.

Your TOT tag contains some elements named .Target and .TargetDev1 and .TargetDev2. Set Target to the time where you want to signal needed maintenance. .TargetDev1 and TargetDev2 can be set to give you advance warning that the maintenace time is approaching.

.TargetFlag, .TargetDev1Flag, and .TargetDev2Flag are booleans that turn on when the TOT reaches the specified value.

Once maintenance has been performed then instead of resetting, simply add the required time until the next maintenance is required to the .Target. This way you also have a total of how many hours or days the equipment has accumulated over its life.

Thanks for the reply, never looked it the TOT, I have seen it but did not know its function.

Thanks!