Hi to all.

I have a redundant configuration of 412-5H CPU. After I successfully made hardware configuration and finished software (automation part), I now must establish a Modbus connection with Modbus devices.

As my PLC is acting as a client, I have used it for a reference example project called MB_TCP_PN_RED_400. I copy/paste blocks FB913, 914, 915, and all DB's that are referenced to them, from the example project to my project.

Just like in the example, I have called FB915 in my OB1 and OB100.

My first question is - how can I change input parameters in DB915 (instance DB of FB915 - MB_PNHCL), as it is instance and not shared? I know I can "manually" use move block, but is there any other way?

Also, if I understood, I must configure FB915 (DB915), and also DB1 (CONTROL_DAT), and DB2 (MODBUS_HPARAM_PN_2), directly from the DB table?

Thank you for your answer in advance.

mopS04

hi Kustom,

there is also an application sample with video and documentation, that describes what to do:

Modbus/TCP - Standardized and redundant Communication of PCS 7 with Third-Party Systems

 hope this helps,

regards,

 Thank you mopS04. I will check the link that you shared and will write here again.

Kind regards,

Petar

I'm sorry, I have made confusion, I made mistake in the topic name and my questions.

Please ignore my first post on this topic. Thank you.

This is my (network) configuration:

I have Modbus communication via integrated PN and also via CP443-1.

Via integrated PN, I'm acting as a Client (I'm controlling burners and boilers).

Via CP443-1, I'm acting as a server (I'm sending information to the SCADA system).

So, basically, I have two types of Modbus communication. Firstly, I would like to concentrate my questions on Modbus via integrated PN - acting as a client.

I have uploaded the sample project "Modbus_PN_CPU_Red", and copy/paste all blocks from there to my project.

In DB2(MODBUS_HPARAM_PN_2), I have edited DB2 table (picture attached).

In DB1 (CONTROL_DAT), I also edited the table (attached to the same picture at the bottom).

Like in the example, I have called FB915 (MB_PNHCL) in OB1 and OB100.

My first question is, do I need to call some other function or change parameters for establishing a Modbus client? To exchange data between me and the server(burners and boilers), I will use send and receive blocks, but let we leave that for another question.

Again, sorry for making confusion with my first post. And thanks to everyone in advance for help and tips.

Kind regards,

Petar

Question about connection ID... Please see the picture attached. Must these IDs be the same (for the same connection)? I mean, connection 0A from DB2 must have the same ID just like connection 0A from DB1, and the same story for 1A?

And also, when I have multiple Modbus connections, these IDs must be different for each connection?

Thank you in advance.

Wüstenräuber

Hi,

the IDs must be the same in CONTROL_DAT and PARAM-DB. And for additional Modbus block instances you need other ids. The ids must be unique. 

In your param DB I see, that you parametrized 1F6 for local_tsap_id. This is not correct. As a client this local parameter is not set.
Please use the "Modbus wizard" for configuration of the parameter datablock, this prevent errors in the parameterization.

Wüstenräuber

 Hi, back to this problem after some time (I was on some other projects in the meantime...).

After using Modbus wizard software, do I need "manually" to create networks also in NetPro with the same ID and IP address, for every client I have? Also, is that need to be done when I'm acting as a server?

Thank you.

Wüstenräuber

Hi,

no, when you use the internal PN interface of the PLC, then the modbus block takes care about the connection establishment. They are not configured in NetPro.

Regards, 
Wüstenräuber

Thank you.

And what about the CP unit (CP443). I had it in the same configuration when I'm acting as Server. I have used the same Wizard to create blocks, but connections are not created in NetPro. Do I need in this scenario to create it by myself?

Wüstenräuber

Yes, TCP connections in NetPro must be generated by yourself. The wizard doesn't have access to NetPro. 

For client you must insert an active TCP connection and for server you must insert a passive TCP connection. It is also described in the manual and in the delivered example project you can see it as well.

Wüstenräuber

Again, thank you very much. Your answers are very helpful and clear, as always.

I will try it now, and ask if I find something else unclear to me.

For now, one more thing- for CPU443, do I create a connection under the selected tab (see picture).

Because I don't have this table for creating connection when I select CP443-1.

Also, when selecting Connection type in the drop-down menu, what type should I select, S7- connection or TCP connection? Because in the S7-connection I can select some of the integrated connections and CPU443 also, but in TCP connection, only CPU443 is visible and greyed out.