How many CXM modules can be configured in one M580 platform, on local rack, remote rack, or DIO ?
A CXM can be scanned only by one scanner. Today, only the CPU.
Each scanner has its own capacity to scan DIO (and RIO for the CPU): in Kb IN and OUT.
The CXM can be configured to be scanned in DIO or RIO from the CPU.
The max size of the process image of the CXM is 4Kb IN / 4Kb OUT.
Several CXM can be declared behind the same scanner. The limit is the capacity of the scanner (for ex the CPU model 4040 can support max 24 Kb IN / 24 Kb OUT in profile RIO + 2 Kb IN/ 2Kb OUT in profile DIO, so around 6 CXM fully loaded in RIO + 0,5 CXM fully loaded in DIO (one CXM supporting max 4Kb IN/4Kb OUT).
When using a CXM in the FAST, the RIO profile must be used, and the limit of the scanner of the CPU in that case is 5Kb IN/5Kb OUT. So, no issue with medium loaded CXM. But not possible to declare more than a fully loaded CXM (4Kb) + a 2nd CXM partially loaded (1Kb).
Last, all the IO scanner resources are shared with the other DIOs connected on Ethernet (for instance, there is no other RIO devices. And the RIO drops are using different CPU ressources CPU).
Local or remote rack is indifferent...
Each scanner has its own capacity to scan DIO (and RIO for the CPU): in Kb IN and OUT.
The CXM can be configured to be scanned in DIO or RIO from the CPU.
The max size of the process image of the CXM is 4Kb IN / 4Kb OUT.
Several CXM can be declared behind the same scanner. The limit is the capacity of the scanner (for ex the CPU model 4040 can support max 24 Kb IN / 24 Kb OUT in profile RIO + 2 Kb IN/ 2Kb OUT in profile DIO, so around 6 CXM fully loaded in RIO + 0,5 CXM fully loaded in DIO (one CXM supporting max 4Kb IN/4Kb OUT).
When using a CXM in the FAST, the RIO profile must be used, and the limit of the scanner of the CPU in that case is 5Kb IN/5Kb OUT. So, no issue with medium loaded CXM. But not possible to declare more than a fully loaded CXM (4Kb) + a 2nd CXM partially loaded (1Kb).
Last, all the IO scanner resources are shared with the other DIOs connected on Ethernet (for instance, there is no other RIO devices. And the RIO drops are using different CPU ressources CPU).
Local or remote rack is indifferent...