et200sp energy meter - modules limitation per PLC

Hi,

I would like to kindly ask you for a bit of support.

I am at the process of building an energy management system based on s7-1512sp - profinet gateways + AI Energy meters and have found in the documentation some points concerning the limitation of the WRREC and RDREAD async. function calls (max 10). Those functions are used by siemens own example FB_DRV for reading and managing of AI Energy Meter data.

As far as I understand the sum of FB_DRV block Comm_Resource_Counter parameter must not exceed the limitation( which is 10 WRREC and 10 RDREAD).

Would like to ask if am correct.

1) The implication of the async. calls limitation is that i can only work with 10 Energy meters per PLC?

2) Would it be possible to manualy maintain the calls by means of busy, ready, etc. block status signals or sequentially calling the reads/writes  with some kind of state logic?

Appreciate your hints.

Krystian

Hello,
Have a look to this FAQ.
What restrictions are there for active jobs when communicating with "WR_REC/"RD_REC" and "RDREC"/"WRREC" via PROFIBUS DP and PROFINET IO?

You should not have more than x jobs active at the same time (where x depends on the CPU).

In the system manual of the 1500 (V2.0), chapter 7.3 (asynchronous instructions) , you can read:
For the RDREC instruction, an S7-1500 CPU can process up to 20 jobs in parallel.

If the maximum number of simultaneously running jobs for an instruction is exceeded, the instruction returns error code 80C3 (lack of resources) in the STATUS block parameter. The execution of the job is stopped until a resource becomes free again.