Modbus communication between USC-B5-TR22 and SM35-J-RA22

[LeonMötter]

Hello to all,

I am working on a new system where a Unistream B5 TR22 is a Modbus TCP master to 11 Samba PLC's Nothing to exciting but my biggest problem is a lack of knowledge. This is only my second project with a unistream PLC, with the first being a very straight forward ladder program without anything special. i do have a few years of experience with visilogic so that side is not a problem.

What i already figured out is how to make the set-up on the master and slave side. the thing i don't get is addressing between the devices. In visilogic i could literally select which mb,mi,ml i wanted to read or write. Now i don't see that option. how does addressing work between these devices?

At the moment i am still waiting on the unistream plc to arrive, so that i can try some stuff out, butt before it arrives i would like to make a little headway before that.

 kind regard's

Leon Mötter

[Flex727]

It's very simple, if a bit tedious. In UniLogic, go to PLC Communications, Protocols, MODBUS, Masters, Panel Ethernet, Add New Slave. Once you do that you can add new operation which includes assigning all the addressing that's compatible with the Vision PLC.

The UniLogic Help file tells you everything you need to know - check it out.

[Joe Tauser]

In the Vision Help, do this:

Search "slave addressing"

Choose MODBUS Slave Addresses

Click the hyperlink MODBUS, IP

On that page, scroll down and click the link Slave Addressing

On that page, click on the green "Enhanced Vision Division".

This will give you tables of how Vision memory is mapped to Modbus registers.  Take a look at that and post your questions.

I've had a conversation with Cara (the Help writer) about how hard this is to get to and there's nothing she can do about it - it's got to do with the software they use.

Joe T. 

 

[LeonMötter]

Thanks for the information.

So if i understand the table correctly adressing for me should be as followed:

if have got 3 adresses to read and write

• I16 in the table a HEX start adress of 6000h which converts to 24576 add 16 and you get 24592
• MB501 in the table a HEX start adress of 0000h which makes it really easy because then it should be just 501
• MB500 same as MB501 so just 500

At this point it seems to easy, so either i have been wasting your time or i have missed something 😆

[Joe Tauser]

It's easy if you understand how Modbus addressing works and if you know where the secret decoder table is.

It sounds and looks like you've got it. 😁

Joe T.