Modbus rtu with rs485 circuit board

HI ALL
Can any one help me to implement a modbus slave board
any one have a complete circuit board for a mod bus server ?

Modbus RTU is a protocol that can be run on a wide variety of serial interfaces, including RS-485.

What sort of device do you need to connect to the RS-485 network ?

A "complete circuit board" could be anything from a TTL/RS485 converter to a complex automation control system.

Wait, I see your other post.

What exactly is a "Mini Modbus with RS-232" ?

Just buy and Arduino and download a Modbus master or slave for it.

abbas.a.fahes said:

complete circuit board for a mod bus server ?

Click to expand...

Modbus is a communications protocol, a set of rules for transferring data. It is not hardware. There is no circuit board for Modbus.

Modbus runs on RS-232, point-to-point, or RS-485, point-to-point or multidrop, or on Ethernet.

RS-232, RS-485, and Ethernet require hardware circuit boards, but Modbus does not because Modbus refers to the data packets carried by the electrical hardware layer.

Some PLCs use modular Modbus modules which include hardware like 232/485 or ethernet, but they also have the firmware that handles the communications according to the rules of the Modbus protocol and which interface to the PLC backplane.

I'm actually doing a project right now where an Arduino is giving me a quick-and-dirty Modbus RTU interface.

Arduino Uno R3, a Canadian-made unit from OSEPP.
RS-485 Shield v2.1 by LinkSprite.
Two-function simplified Modbus library, "modbusino"

It was remarkably easy and simple to set up and get running. It "just works" over USB, and took just a little soldering to get the RS485 interface working.

But "throw an Arduino at it" might not be the right answer to the OP's problem; his interface device or comfort level with microcontrollers might not be appropriate.

And what was the total cost Ken?

Ken Roach said:

...What sort of device do you need to connect to the RS-485 network ?...

...Wait, I see your other post....

Click to expand...

...and don't forget their other first post, which I think might be the root application they're looking to implement here?

Maybe, or maybe not?

If it is all related then they appear to be trying to connect some "sensors" using Modbus connected to a SIEMENS S7-1200 via an add-on Communication Board (CB 1241 RS-485).

If not, ignore my ponderings...

G.

Including shipping and taxes, about $50 USD.

If there's one thing that experimenting with Arduino and other microcontrollers has taught me, it's that the cost of industrial electronics is not in the hardware components. It's in the engineering, the enclosures, the testing, the documenting, the inventory, the manufacturing... everything else.

Lots of things are really inexpensive when they run for twenty minutes on a breadboard on your desk. Doing something right that will hold up to the real world is a lot more time and trouble, and appeals to a different market.

If I end up deploying my little microcontroller project into the field, I'll try to buy some Ruggeduino boards.

Thanks, George; the OP created posts faster than I could follow him.

Geospark

IT'S 100% CORRECT

As an Arduino fan I agree with you 100% Ken.

Ok abbas,

That is fine, but please do try to keep all your questions related to the same issue in one thread only. You have several people assisting you on the same issue in several different threads. If you want to bump your thread back to the top then simply reply in the thread with "BUMP". If you have a new question related to the same topic in some way, then simply ask it in the same thread, rather than start a new thread.

If we can pull it all together, perhaps here, or even back in your first thread where you actually mentioned the S7-1200, etc., then we can all keep up. This will also make it a little bit easier for us to follow your train of thought.

You are trying to ask pretty much the same thing in different ways. You are not providing enough details, or are actually providing less and less details since your first post.

I am not being critical of you here. I am trying to help you to help yourself.

Can you post specific details of the "sensors" (make/model number) that you want to connect to the CB 1241 RS-485 using Modbus. If they are indeed RS-232 based sensors, then yes, you will need an RS-232/RS-485 interface converter of some sort.

Regards,
George