Im using the „modbus TCP 10“ librarie and 2021.9 software. It works on all modbus modules I got exept from one.
Im trying the comunication with a program called "modpoll" and I can use the standard settings for the communication. On the last one I have to use the -0 option. In the help meny the explanation is: "First reference is 0 (PDU addressing) instead 1". I cant find any parameter to the FB for this option. How can I overcome this problem?
Hi Pudderjager,
to be honest, I don't really understand what you're trying to do -I think I'm still in Christmas mode ;-) I understood the following, you are using Modbus Poll as Testclient --> in that case you've implemented the modbus tcp 10 lib as a server, right? In standard operations (which function code?) everything works fine, but using a special option the call failed? I'm by far not an expert in Modbus Poll, but I've played a bit around and did not found this "-0" option. Can you give me a few more details: [list] [*] Are my assumption correct, if now please describe the settings and tools [*] Which function call do you use on which registers [*] Which errors are shown in Modbus Poll and maybe the function blocks itself (wDiagCode, wAddDiagCode) [/list] Frank
If i could show you some pictures of my problem it would be easy to see what Im struggling with. Maybe you can send me your email and I can reply with pictures?
PLCnext 1152 controller and PLCnext E 2021.9 with "modbus TCP 10" librarie: FB: "MB_TCP_Client" return this errors after 60 second: 16#C050 and 16#C101 FB: "MB_TCP_FC3" return error: 16#C010 (Thats not a suprice!) The "Modpoll" software is a commandline software Im using for testing connection and find the correct options for the communication. Im running this software on my PC when Im in the same network as my PLCnext. Its here I have to use the option -0 to get data from the modbus at register 1 - 10. On other modbus device I can communicate with and without the -0 option. When Im not using the -0 i got this answer: Replay time-out. Here is the command im using: modpoll -m tcp -0 -r 1 -c 10 192.168.1.1. Port is default 502, slave adress is default 1. The modbus device is a Teltonika RUT950 4G mobile router. Link to the manufacture is: https://wiki.teltonika-networks.com/view/RUT950 and here is the link to the modbus manual for the router: https://wiki.teltonika-networks.com/view/RUT950_Modbus The decription for this operand "-0" is: "First reference is 0 (PDU addressing) instead 1".
Sorry for the delay.
Here is the answer from the PLCnext Engineer support team: [quote]So I can't say anything about the third-party Modbus software. our client works with the protocol address so the start address is 0 = protocol address 0. Modbus works with protocol address (0) the MB Rigister address starts at 1. How the server evaluates the Modbus protocol address I cannot say because the customer has to ask the software manufacturer. The protocol address 0 should be the MB register address 1. therfor the offset of 1 I don't see any fault on our part here. Furthermore, the latest modbus library version 11 should be used.[/quote]
I will upgrade to version 11 and test it. Maybe ist solved there og maybe its a problem with the server. I will update when its tested.