Freelance AC900F boot parameter calculation(specially PRAM)
I need one information.
We are using AC900F in redundant configuration in one of our project. When I was Downloading the program to Controller, it was getting terminated before 100%, resulting the controller to go in Fatal error sometimes and Stopped. Its getting stopped everytime when the change object load or whole station load are terminated prematurily(before 100%).
After that we changed the Configure Data(PRAM) from 7000 to 2500 or 3500 in some location. Now the program was getting loaded fully and working.
Can somebody tell how to calculate the required size for PRAM for smooth operation of controller in a project
At site the second controller(which is acting as redundant) is getting rebooted frequently. As this is the redundnant controller so this is not causing any problem in plant operation, but still, what can be the reason for rebooting of controller itself(without any intervention).
Follow the guidlines below and everything should be ok:
1. Network buffer, Interface Objects and redundancy memory should be set up so that the required values would not exceed the set ones. I normally suggest to change them only if You have a big project and starting to go near the limit. If not, leave them be.
2. Max. no. of Objects and PRAM is really a package deal. When setting them You also set RAM value, which is not even visible in there. Anyway when setting these parameters what You are really doing is alocating controller memory, as all three (PRAM, RAM and Objects) take up space in controller application memory.
When You increase PRAM, it decreses RAM. When You increase no. of Objects, You decreas RAM. And the other way around.
What You saw was result of increasing PRAM and number of Objects (mostly PRAM from what I can see) that left almost no memory to be alocated to RAM. This resulted in failed atempts to run Your aplication after the download (or maybe even in failed downloads, depending on when exactly the progress bar stopped).
I can't give You here any "golden values" form PRAM and RAM as this depends on both application and system architecture (used controlelrs etc.). You can find more info on that in Engineering manuals. What I can suggest is changing this values (again) only when needed. And You can easily see when it's needed thanks to .RAM_Free and .PRAM_Free variables of Your controllers or even better through their web interface (see the bargraf in upper right corner of the main interface page).
As for the other question - You should seek support from Your local ABB representatives. They will require You to download logs from the controller (again use web interface to do that), so You can send them right from the strat to speed up the process.
Hope this helps,