Number of timers and counters in GE and AB

[Iman]

Hello everybody,
I'm searching the product of GE Rx7i family and also Allen Bradley ControlLogix 1756 series to find the number of timers and counters in each CPU modules of these series but I couldn't find anything. Interesting thing is the GE has mentioned the number of timers/counters in Durus family but not Rx7i!!!!!!!!!!
Can anybody help me about this in GE and Allen Bradley?
Thank you

 

[bernie_carlton]

Some types of PLCs have pre-assigned memory assignments and thus fixed numbers of such structures as Timers and Counters. A 'number' for these would then be a valid specification. But in many others the memory area can be used freely and thus the number of Timers and Counters is up to the programmer. While than a 'total memory' specification would be appropriate, a count of specific memory types would be misleading

 

[Iman]

Thanks Bernie
That is very informative for me. I thought it was directly related to the hardware. So it is related to memory.

 

[Iman]

I've forgotten to say that as you said in some PLCs the programmer can define the number of timers and counters but I think in that condition they have some limitation too. I mean at least the manufacturer should mention a maximum number of timers and counter. Programmer can not assign all the memory to timers and counters.

 

[bernie_carlton]

In most PLCs the timer/counter instructions use a certain number of memory addresses as do other types of memory storage. Listing the total memory size and the sizes required by the various data types should be all that is neessary.

Of course some high speed counters and very fine precision timers may be implemented in hardware which would be listed seperately.

In Allen Bradley Micrologix, for example, the number of high speed counters depends on the chosen modes of operation and the number are listed by mode.

 

[Iman]

Thank you again for your quick responses. I think I should see the memory allocation or instruction set manual of GE and AB to find the maximum number of timer and counters which still I haven't found it.

 

[bernie_carlton]

Good luck with that. What you seek is similar to expecting the maker of a cargo truck to list, instead of maximum net weight or volume of cargo, the maximum number of washing machines it can carry as a standard specification.