Programmatically obtain the slotnumber for a module

[plcnovel]

HI aLL
Is there a way in RsLogix5000 to obtain a slot number for a I/O card in Control Logix chassis programmatically? Thanks in advance

 

[Ken Roach]

Hmm. When you send a Message, you have to specify the Slot number in the CIP Path.

You can do this the other way around, by getting the module identity from each slot using a "Device WHO" command in a MSG instruction.

Knowbase Answer ID # 23386 has useful information about a module's response (specific in this article to a CPU, but applicable to others) to the Device WHO function.

What is the purpose of this?

 

[ettikudiappan]

I too have a requiremtn like this. We have 3 PLCs in one chassis, one master and 2 slaves. The 2 slaves program are identical except for checking a few bit from the Master PLC. Now I need to maintain 2 versions of essentially the same program. If I could modify the slave program based on which slot it is in, then I need to maintain only one program and can download the same program to both the Slaves.

What is the purpose of this?

 

[RSL]

Actually you would not be able to download the same program. Logix5000 will not let you download the program unless the Controller properties specify the correct slot. Meaning, you can't download the "exact" same program to controllers in different slot numbers.

At a bare minimum each program would have to have the slot number for the controller set differently.

RSL

 

[MichaelG]

So is what he really after is identifing which slot the processor is in?

This I can see a use for - Same program, just change the slot the processor is in and download again, the logic changes which bits control its actions from the master.

I don't seem to be able to determine the slot the processor is in using GSV. I can get the serial number of the controller but not which slot it is in. Any idea's???

edit: Maybe Ken had the method use tech note 23386 to scan every slot looking for a CPU with the correct serial number as read using a GSV. Don't have a CPU to try this on.