Siemens s7-1200 , GET and PUT

Hi!

I have a rather basic question, I have only one s7-1200 on my desk so I can't try this myself and I have failed to get a good answer.

I have one s7-1200 at my customer.
He will now get a second one with a new s7-1200.
I wan't to communicate between them.
I want to do this as easy as possible since it is just ONE integer that is transfered.
I found out that the instruction GET could be a good one?

Now to the question. Is it possible for me to simply insert the GET instruction in my new s7-1200 and be able to read from the existing s7-1200? Meaning that I don't have to modify my existing s7-1200? It would be great if I didn't have to modify the existing PLC.

The manual failes to describe this, or maybe I'm just not getting it.

/Tim

Also there is TRCV_C. Same goes here, is it possible to have the TRCV_C in my new s7-1200 and no changes made in the existing s7-1200?

I used Put/Get blocks with other S7 PLCs. All I had to do is configure unspecified connection and configure blocks on your/new plc side and no programs modification on existing/old plc side needed.
I would expect put/get to work same way on S7-1200, even i didn't try these blocks with S7-1200.

Thanks alot for usefull answer! Then I know how to proceede with my programming.

Yes you can do a GET from one PLC with no modifications to the code of the other PLC if they are in the same project.

I have used this feature heavily on the S7-1200 in TIA Portal V12 and newer. The 'other' PLC just has to not have its security set to prevent the communications: fortunately (or not from a security standpoint) that open communication is the default security setting.

I would however recommend that you move the data that you are getting into its own well documented data block on the 'other' PLC. The comments should clearly explain that another PLC is GETting this data. It is a nightmare to troubleshoot code that relies on the hardwired position of data when code changes in the future - and the PUT/GET hardwire the offset of the data when you compile the code. If you just GET data from another PLC, its almost a 100% guarantee you or another person will break that code inadvertently by making some innocuous change to the 'other' PLC.