Max Used memory reached 90% in AC800m Controller
I am Using ac 800m controller with 5.1 version
Max used memory in controller diagnostics faceplate is showing 90%
how it will effect my system stability?
how can i reduce it?
my controller load is still under 75%.
Voted best answer
If you are talking about Max Used memory during download, then this is probably OK.
During a download, you have 2 copies of your application, the running version and the new version. After the download is complete the old version is removed and the memory is returned. However, you should continue to monitor your memory usage.
- You must have free memory larger than the size of the largest application in your controller or warmstarting your controller will take an excessive time.
- You cant "reduce memory" unless you simply put less software in the controller. There are no options like compressing code, changing compiler settings etc. If you want to use less memory either move some software to another controller or buy a controller with more memory.
The controller CPU load is a different question.
- Is your "Total Load" ( ie cyclic + system load) 75% ? - If yes, its OK except you might find the controller overloads a little during warm start.
- Is your "Cyclic Load" over 70% ? - If yes, your controller is overloaded, you could begin to loose OPC communications and possibly control tasks might be delayed. My personal opinion is you should try to avoid cyclic loads above 50 to 55%%, which makes the maximum load in a controller around 80 to 85% ( 50% cyclic + fixed 30% system load )
Long term stability of the controller is a different question. I have seen controllers that use a large amount of memory like this show signs of memory creeping or memory fragmenting. The practical effect is that downloading a lot of code changes during commissioning can become slower. Cold starting the controller has resolved these issues. I have no idea if these issues could affect your site.
More than One Application in the Controller
Less spare memory is needed when there is more than one application in the
The on-line changes are done to one application at the time. This means that if
changes are done to more than one application in the controller, these changes will
not take effect in a synchronized way.
Example: One application requires 50% used memory and 70% maximum used
memory. If you split this application into two equally smaller applications, it will
still require 50% used memory, but only 60% maximum used memory, since the
extra memory needed for the on-line changes will be half.
This all is from technical_configuration_manual
Without dividing applications is it any other way to reduce memory consumption?