Hello,

regarding informations of connection between two PLCs via ethernet, S7 communication, ... you will find in the online helf of STEP 7 (TIA Portal) V11. Open a block (FB, FC or OB) and you can use the instructions. On the right side you can open the folder for communication instruction and there are system function for programming of communication. Under "Open user communication there is example the "TSEND_C" (Send data via ethernet) or "TRCV_C" (Receive data via ethernet). Mark this modul and put of the "F1"-tape. After you will see the online help for this part.

With best regards
Cicero

0_Einstein

Milosh

Ok, thanks.

Let's say that I have PLC 1, and PLC 2. How to check bit state from PLC 1 and set some bit on PLC2?

Let's say you create a couple of DBs in each PLC. One is for sending to the other PLC and one is for receiving from the other PLC.

[Note: this is not necessarily the best way, but to help explain it....]

In PLC1, DB1 (for reading by PLC2) is created with several tags (tag1, tag2, tag3, etc) of BOOL datatype.

In your PLC logic, you set the DB1.tag1 by the status of your test bit. In PLC2, you read that remote DB and store it locally to DB2 (for data from other PLC). Check DB2.tag1 and use it in your logic normally.

Some things to do is how you handle loss and restoration of connection between the PLCs. You might want to default values to 0, or set a global comm fault and handle that fault. It is application and design dependent.

There are some examples in the FAQs that talk about doing the exact thing you want to do.

 Okay
what is the thing that takes the first address from DB1 in PLC1 and puts it in DB2 in PLC2?