micrologix 1200 HSC question

This seems like an easy one but I haven't found the answer yet.

I have a micrologix 1200 and a program which uses a STI and IOM to control some outputs based on the value of the HSC.ACC. My question is wether the value contained in the accumulator is updated and available during the scan, or is it only updated once per scan? I would think it would update continuously, but I don't see this stated anywhere. I have seen some mention of a UA (update accumulator) bit for ML1000, but nothing like this in the ML1200 documentation.

Can anybody enlighten me on this?

Thanks

Value in the accumulator is ALWAYS updated continuously, whether counting is enabled or not.
I will find this out in the manual and post it.....
I was wondering the same thing for an app I was working on and it states it in the PV1100 manual programming reference I believe....

Maybe I'm splitting hairs here. I know the accumulator updates continuously, but is the value in the accumulator always up to date as the program scans. Put another way, assumuing I am counting up and we look at any given single scan, will the value of HSC.ACC be higher on the last rung of logic than it was on the first rung?

My guess is the answer is yes?

I will take a stab at this,.
The HSC routine is working OUTSIDE of the ladder softwware, thus the ACC value is NOT AFFECTED by Scan Time.
If the unit that is providing pulses to the counter (Input 0)on ML1200, than the accumulator is updated continuously. If the example (encoder) is stopped, then the accumulator is stopped.
The only difference is HOW you use your accumulated values to complete a task in your user defined subroutines. This is where the scan time will play a factor.
If this is what you are worried about, use the HSC PLS routines. They are completely set aside from your ladder logic, and will occur as fast as needed in your application.....

All right, thanks for the information. I have been reading up on the PLS function and it sounds interesting. I think I will give it a shot.

Thanks again