Hi everyone,
I've been struggling for a week on how to setup a Bristol ControlWave GFC as a Modbus Slave. I thought I would only have to change the mode port (I am using COM2(TB2) for tests) to modbus mode (either ENRON Slave or GOULD Modbus Slave), someone told me it's necessary to load in an application in other to make it modbus compatible, but someone else also told me that modbus is a native protocol in the ControlWave, that got me confused!

In a nutshell, what should I do to have my Bristol Controlwave communicating as a Modbus Slave equipment and how do I setup the modbus registers I want it to make available in my communication? I am using Modscan for simulation test.

Thanks in advance.

 

Hi friend,

All the bristol products mostly have the same kind of configuration for serial communications.

first of all you will select the COM port this comport has the feature to select which kind of protocol you are going to use according to that you are configuring the Function block with its associated parameters. You will be using the CUSTOM function block where you will define all the parameters related to your serial communication. i have done for ControlWave Micro & Control Wave,it will be most the same for GFC.

your confusion is with Enron Modbus or Gould Modbus.these are both are two different protocols with different messaginf formats. in control wave each port has different protocol selections.i guess this mite solve your problem. if any questions feel free to mail me [email protected]

 

if you are using Enron Slave as your communication protocol then use DNbus simulator which comes from Calta.com & if Gould Modbus Slave then use MDbus simulator this also comes from Calta.com.

For gould modbus the register addressing format will be:-
AI's :-4XXXX
Input registers :-3XXXX
& DI's:- 1XXXX

For Enron MOdbus the register addressing format will be :-
DI's & DO's:-1XXX & 2XXX
AI's & AO's:-7XXX & 8XXX

This will be more usefull.

Ganges

 

If you've been struggling for a week to do that, you need help from the vendor. Bristol is now part of Emerson Process Management, and depending on where you are, your local Emerson office can probably point you to support. Your time is valuable, and that's what vendor support is for.

Walt Boyes
Editor in Chief
Control and Controlglobal.com
www.controlglobal.com

Mailto:[email protected]
Read my blog SoundOFF!! At www.controlglobal.com/soundoff

 

Hi Walt,

I used both support local and international, but both gave me 2 different opnions. one said I don't need to load in anything special to have modbus and the other said I would need to have an application that makes Bristol speak Modbus, that got me confused and forced me to post an ask for help here.

 

Hi

this is given in the Manual of GFC as shown in below about COM2 & with this Configuration if you are using the port TB2 it will not work. please check for this & one more question, may i know upto now what you have done to establish the communication


COM2: From the factory, RS-232/RS-485 Communications Port COM2 (8-position Terminal Block TB2) on the CPU/System Controller Board defaults to 9600 baud, 8-bits, no parity, 1 stop bit, BSAP/ControlWave Designer protocol operation (RS-232).

Note: COM2 is assigned to either an optional Radio/Spread Spectrum Modem or a 56K PSTN Modem (mounted piggy-back on the CPU/System Controller Board). If one of these options is present, connector TB2 should not be used.

In lieu of one of the piggy-back mounted communication options, an external Radio/Spread Spectrum Modem may be mounted inside the unit on the Radio Mounting Bracket. An external Radio/Spread Spectrum Modem is interfaced to COM2 via connector TB2 on the CPU/System.

 

Hi Mr. Gangadhar,

Thanks a lot for your clearance, but still have some doubts, first what do you mean by CUSTOM function Block? I downloaded something called briston_communication.zwt. This looks like a code used to implement the MODBUS in the Bristol, hopefully not. I hope I won’t have to use some programming language to make it speak modbus. If so, is there some ready-to-use code I could download off the internet in order to save time and have easy maintenance?

Thanks a lot!

 

If I am posting 2 answers to the same question I appologize, but I couldn't see my last message, so let me answer it again.

What I've done so far was: I changed the COM2 configuration to ENRON and Gould Modbus both slave, none of them worked. I am using Modscan32 to simulate the master and I've tried ENRON RTU and Standard RTU with no success.

I don't know if I can't have modbus at COM2, I tried COM2 because just like the rest of the COM ports teh Local View allows me to change from BSAP to ENRON or GOULD Modbus slave, so I am assuming it's possible, maybe not, but I tried everything with COM1 (TB1) and it didn't work either.

If it's necessary a Custom Function Block to make ControlWave GFC to speak Modbus, what exactly it is? is it something I can get from the internet and use it? Where can I find resources on that?

Thanks again

 

Hi

i will mail you the code related to the Modbus communication the code is the combination of CUSTOM function block & LIST block. you need to take help of Open BSI HELP to understand the code its simple and not much typical.

in short LIST's are used just for the messaging format of Modbus(RTU). Because its very hard to tell everything in the mail rather self practice i guess this code will help you.

 

Hi, stumbled across this post and might be able to help if you are still having trouble.

Are you still having trouble with establishing Modbus communications via the GFC?

Thanks,
David

 

I have the same kind trouble. Could anyone give me a step-by-step how to configure ControlWave as Modbus Slave?

Best Regards

 

Hi, do you still have problem with this issue? Let me know, I could help you ([email protected]), Regards.