Issue
Is there a specific amount, or percentage of free memory that must be maintained for Continuum controllers to operate?
Environment
NetController
CX9900
CX9940
Infinet
i2
ACX2
b3
Cause
Is there a specific amount, or percentage of free memory that must be maintained for Continuum controllers to operate?
Resolution
There are no published metrics or guidelines regarding the use of Continuum controller free memory.
For most of the Continuum controllers there is no required minimum amount of free memory in order for the controller to function properly. The notable exception to this is the CX99xx. Remote validation will stop working in the CX99xx if freemem goes too low. This is because the system memory and the user memory come from the same heap. Also, in the CX99xx, if a Plain English program uses a commport to read and write data, and the controller has insufficient memory to switch from a RAW port to AutoSet, the controller will lock the commport. A safe target for freemem is 15% of the total.
These issues were fixed in the NC2/ACX2 by having separate heaps for memory allocation by the system and OMS (object management system).
The newer IP level controllers and the i2/b3 controllers can be loaded up until there is no freemem but be aware that as you load up the controller memory with programs, the scan time will typically increase.
