Today I have on my workbench an interesting PLC, awaiting review: the Industrial Shields ARDBOX PLC 20 I/Os, produced by Boot&Work Corp (Barcelona, Spain). With 10 inputs (5-12-24Vdc, plus 0-10V analog) and 10 outputs (two 0-10V analog outputs, 8 relays), digital outputs, SPI and I2C interfaces, plus RS232 and RS-485, this is one of the smallest PLCs in the Industrial Shields product range.
At a first glance, it offers more options than the Controllino Mini. Plus, it’s highly configurable: one can use the two switch banks to configure the communication interfaces. It’s also much bigger than the Controllino. But why?
Let’s take a look inside this thing…
Opening the case is quite tricky. There are four plastic tabs holding the two halves of the case together, one tab being located just under the red plastic tab used to hold the ARDBOX on the DIN rail. There’s also a spring under that red plastic thing, easy to loose if you are not careful when disassembling the ARDBOX.
The plastic tabs are quite small and easy to break. I’ve managed to break one (see the red circle in the picture below), even if I was very careful and I had good tools to open the case. To me that’s an acceptable loss, this particular ARDBOX is for my own use and testing.
Inside there’s a nice surprise: there’s an actual original Arduino Leonardo driving this thing. In a way, this device is nothing else but an Arduino Shield.
On the top side we have the power supply, then the Arduino Leonardo I’ve mentioned before, then the “shield” where all the fun happens. All the boards are held together using plastic raisers, which proved to be quite difficult to remove. I’d say this device will definitively work fine no matter the environment – vibrations and such. The only thing I would complain is that the capacitors on the power supply can touch the bottom of the Arduino Leonardo board. I don’t know if that would be a problem if the ARDBOX is subjected to a lot of vibration – only time will tell.
Note that some relays are connected to PWM-capable pins of the Arduino Leonardo. Extra care should be taken in software when working with those relays.
There’s a switching mode power supply implemented with two P3596 IC’s from Unisonic Technologies, delivering a current of up to 3A. The user manual specifies an input voltage of 12 or 24V, with a current of 700mA. For a 12V supply, with all relays ON, I’ve measured a current of 495mA. The current was below 200mA for a 24V power supply.