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Author Topic: DIY MODBUS I/O board.  (Read 9295 times)

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« on: August 20, 2011, 12:33:44 PM »
Hello everyone,
I usually don't visit this forum much as I tend to hang on the Yahoo user group, some of you probably recognises me from there. Since there might be members here that don't visit the Yahoo group much I thought I'd mention the following here as well in case anyone's interested.
I've designed a small I/O board that can be interfaced to Mach3 over serial (RS232) MODBUS RTU. Here's a short list of features:

* 4 digital inputs, opto-isolated, can be adapted to "any" input voltage. Positive or negative logic on each inout, LED indicator on each input.
* 4 digital outputs, open collector, 50V, 500mA. LED indicator on each output.
* 2 analog inputs 0-5V, 10 bit resolution (oversampled to 12bit in firmware).
* 1 analog output, 0-10V 10mV resolution.

It's been designed to be easy to build yourself, all thru hole components and no exotic parts, BOM with Digikey P/N's is supplied. If you have the skill and equipment you could even each the board yourself.

All the files (schematic, boardlayout, gerbers, BOM, firmware) and information you need to build one is available on my website. If you're familiar with setting up a MODBUS device in Mach3 then this one is no different but if you're not I have a guide on how to make it work.


Offline DaOne

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Re: DIY MODBUS I/O board.
« Reply #1 on: August 20, 2011, 04:53:52 PM »

Any chance of releasing the source code for those of us that like to play with Pic micos? Very cool project.


Offline DaOne

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Re: DIY MODBUS I/O board.
« Reply #2 on: August 20, 2011, 04:57:45 PM »
Sorry... posted before reading... :)

Please note. The source code for the firmware is not included and I currently don't have any intention to release it. One of the reasons for doing this project was to show some of the capabilities of the MODBUS "driver" I've developed for the PBP compiler. My intention is to license that driver to other developers using PBP who are looking for a MODBUS driver. This application works as a "demo" for that driver. So, the source code is not available.
Re: DIY MODBUS I/O board.
« Reply #3 on: August 21, 2011, 04:37:25 AM »
That's corrent, everything to build one and make it work is there but I'm afraid the firmware isn't open source.