My project goal is to make an automated indoor hydroponic greenhouse. My controls setup will regulate temperature, humidity, lighting and water levels.
I have a Unitronics V350 Vision PLC/HMI combo that I want to use because the software is free and it has a built in touchscreen. There are a few issues with using this as a stand alone controller:
It only has 2 analog inputs.
0-10v or 4-20mA humidity sensors are cost prohibitive for me.
The unit is obsolete.
My idea is to use the mega's generous supply of analog pins with some DHT11/22's for the temp and humidity readings which will be sent to the PLC. This will be viewable on the HMI and the PLC's outputs used to control heaters and humidifiers.
My main question is, what is the best way to get the data from the Arduino to the PLC?
The V350 supports RS 485/232, Ethernet and CANbus.
If it's a PLC, then it is likely to have support for the Modbus protocol over RS485. An RS485-TTL board is very cheap and will allow one of the MEGA2560 serial ports to communicate with your PLC.
Hi,
Many many years ago I used the 350 quite a bit, have you checked the terminals on the back, to make sure what comms you have.
Sometimes they list all the various I/O possible, but some need an extra I/O module.
The 350 is a very nice PLC, the IDE and HMI are very good to work with.
Yes sir! If I remember the manual correctly, you open it up and move a jumper or two to select the comms. The model is V350-35-T2.
You are spot on about the IDE. Makes writing a program and an HMI a breeze
I also have a Micrologix 1400, but good luck getting the software for free! AB will keep their hands in your pocket every step of the way.
Anyway, looks like I'm going to be researching how to get what I need with Modbus.
Thanks for the replies!
