AC800M PM891 Load
One of our customer want's to upgrade AC410 controller to AC800M.
Currently AC410 controller running with load 93 to 97%. Only S800 DI/DO's are there.
We are planning to replace AC410 with single PM891.
Is single PM891 can take that load or do I needs to provide 2 controllers by splitting the applications?
No Of IO's - 49 DI Modules and 30 DO Modules.
No of PC Pgm - 1No (Sequence)
Disclaimer : You need to be responsible for calculating the estimated CPU load based on whatever libraries and program cycle times you eventually choose. This isnt a commitment ...
A single PM891 is about the same as an AC450 - So Yes, your AC410 should easily fit into a single PM891.
Because your S800 I/O runs on a bus (AF100) theres no CPU load for running the I/O channels. So the controller can handle quite large amounts of I/O (the same is not true for I/O connected on the controller modulebus). The only load from the I/O channels is whatever library blocks you use for handling I/O presentation and alarming.
If your code is written efficiently, and doesnt use a library with lots of features that you dont need then you can pack a remarkably large amount of code into a PM891. However, without knowing a lot more about how your Prgram is written, how large it is and how fast it runs, it isnt possible to estimate the actual CPU load of your program.
It is likely that AC410 fits to PM866 if translated code is written efficiently.
For example avoid too much tabs in Control modules/Programs editor.
It depends whether your customer needs HMI function blocks for all DI/DO and SEQ, I mean HMI of DCS functionality as PP or BMI library provides. (BMI does not contain HMI of sequence)
You can use Basic AC800M libraries in order to decrease CPU load, but you have to count with additional HMI job related to Sequence. It may take 1 month to built HMI solution similar to AC410 SEQ HMI.
I have experience that 50% loaded AC450 leads to 65% cyclic load of PM866 (using BMI library).
If you can borrow PM866, use Ampl2m online tool for quick code translation, download translated code to PLC and check the PLC load. However translated code needs some manual fixes prior to download, let's say it will take couple of days to fix translated code manually.