I have been experimenting with Connecting Arduino to SCADA systems vis Xbee for the past year and would like to pass on some info.
I have just finished installing and setting up MANGO, and have the following up and working:
Arduino with 6 Analog inputs, 6 Digital inputs, 4 Digital outputs and 2 Analog outputs.
Connected to a DFRobot IO Expansion shield V5 with a Digi Xbee Series 2 Radio.
This communicates AS a slave with Modbus RTU, however, this is where it gets better...
I then use my Digi Connectport X4 Gateway's Industrial Automation(IA) capabilities to convert this to Modbus TCP.
The X4 has a built in Xbee S2 and Ethernet.
Then, the Mango data source simply points to the IP address of the X4 Gateway on port 502, Slave ID 1.
This means that I can can connect to this data from anywhere and not limited to a serial connection.
And it gets better even still...
I can set up lots of these Arduino nodes. I just set a new slave ID in the Arduino code, say 2, set a new table entry in the X4
with a new port, say 503, then direct Mango to the X4 address, 503 and Slave 2.
Analog sensors I have used include, LM35 temperature, light, voltage divider, Pots, sound, current.
I have a fan hooked up to one of the analog OUTPUTS via a MOSFET that I can set the speed from within Mango.
All this over a Digi Xbee Series 2 Mesh up to 3 kilometres (theory) away!
The code Arduino code size is only 6.9K, and I can have as many registers as I want, limited by the speed of the Xbee mesh.
From my understanding, you could also use a Connectport X2, which has just the Xbee radio, and Ethernet, but has firmware
available for flashing that includes Modbus. (Check before purchase, as I do not have one)
So lets look at the price:
Arduino/compatible $25 (DFRobot)
Xbee/expansion shield $20 (DFRobot)
Xbee Series 2 $45 (DFRobot)
Connectport X2 $139 (Sparkfun) (X4 $400+)
So once you have an X4/2 the node cost is only $90, plus sensors of course.
OK so what Arduino libraries you ask???http://code.google.com/p/arduino-modbus-slave/
I AM having one problem that hopefully someone can help me with.
I cannot get the Digital outputs to stay on in Mango. After a couple of reads they go off. I have tried just about every setting,
but have come to the conclusion that it is the Arduino code. I also use ADAMView(advantech), and it also turns off the outputs,
but only when you stop the service, not WHILE IT IS RUNNING like Mango.
Attached Arduino INO. I have stripped out a lot of the comments and simplified the code for ease of use. Get the library from the above link.
Advantech ADAMView DEMO(2Hrs) Full(~$190) http://support.advantech.com.tw/support/DownloadSRDetail.aspx?SR_ID=1-H1VQ1&Doc_Source=Download
(With ADAMView, you use the included TCP OPC server) ASK me for info if you want to run ADAMView on Windows 7.
You can use this system with ANY SCADA package that supports Modbus TCP/IP.
I can also control and monitor the nodes with my Android!!! (But that is another story)