Hi @Martijn-Hemeryck,
it depends what type of output your sensor has. Basically there are PNP (sourcing) and NPN (sinking) outputs.

• PNP (sourcing) typically outputs supply voltage of the sensor when the sensor is in ON state otherwise it is unconnected (high impedance).
• NPN (sinking) shorts the output against GND when the sensor is ON, otherwise it is unconnected (high impedance).

For example digital outputs on our units are NPN.

If your sensor has PNP output and its supply voltage doesn't exceed 24V, you can typically connect it directly to the UniPi's digital input.

If your sensor has NPN output, that's where it gets a little bit tricky. Digital inputs can only distinguish the ON state (voltage 5-24V). Any other state - be that 0V, short to the ground or high impedance (nothing connected) will result in OFF state. In order to use NPN sensor, you need to define the OFF state by connecting the NPN output to supply voltage via pull-up resistor. And there are two ways how to do it, depending on the supply voltage of the sensor

The pull up resistor will bring the OUT to the level of the supply voltage. In the first example it is 24V, in the second example it is 12V. The GND of the UniPi and the GND of the second power supply may or may not be connected, depending on the level of isolation you need between UniPi and the sensor. But that's another story. But the DIGND has to be connected in both cases.

Martin

Hi @baggz,
not that I know of. But proper pH sensors usually have a analog output, so you can connect it to UniPi Neuron's or Axon's analog input.

From your profile I guess you want to measure the amount of nutrients in the water for flowers. If you know basic electronics stuff, I would recommend you some cheap eBay pH sensor for start, such as this. You will learn how they work and how to calibrate them, because they degrade in time.

Martin

Hello @sidoor,
yes, the paper is for protection of the sensor during manipulation and you have to remove it for proper measurements.

Martin

Hello @thenoobiniser and welcome to our forum!

Unfortunately there are no news about the openHAB binding, but it is definitely on our todo list.

In the mean time, you can use the openHAB's Modbus binding together with our Modbus TCP server. But that requires deeper knowledge of how the Modbus works in order to not get lost in the implementation. Now to your questions:

1. No, openHAB can directly run on UniPi, but the response may be slow, because it is a quite complex Java application.
2. UniPi doesn't have to be connected to router and can run completely without network connection.

Martin

@mohamed-dounnani Oh sorry, I overlooked it... Anyway, you can find the formula for analog output in the Neuron Technical Documentation I posted above. The system is practically the same, just with different registers and different formula.

Martin

@blacksoll Those products are only temperature sensors. If you are looking for humidity sensor, take a look at our offer of the Sedtronic products: https://www.unipi.technology/sedtronic-1-wire-sensor-p67?categoryId=3

Martin

Hi @andmo,
I'm not sure what did you try, but from the product page of the ADAM-4017+ I can see that it indeed supports the ModbusRTU, as stated by Tomas. I strongly recommend using this protocol, since there is a built in support in the Mervis.

Martin

Hi @paroxysm,
the post you have probably stumbled upon has been imported from old forum and the attachments didn't survive (sigh). But the old forum is still running and you can check the original post here. So try it and please, let us know, if the plugin still works with current version of Homeseer.

Thanks!

Martin

Hello @mohamed-dounnani,
it is unclear, what type of software you use. Let's assume you use pure Modbus, please correct me if you use Mervis or Evok.

You can find complete information about available coils and registers in the Modbus Registers Map of your unit. Unfortunately, no register contains the calculated voltage and you need to calculate the real value in your program. The calculation formula, which you can find in the Neuron Technical Documentation looks like this:

So in order to calculate the values, you need to poll 5 registers:

• Vref (register 1009)
• VrefInt (register 5)
• Vai (Analog Input 1, register 3)
• AI1vdev (AI 1 Voltage Deviation, register 1025)
• AI1voffset (AI 1 Voltage Offset, register 1026)

Regards,
Martin

Hello @andmo,
unfortunately we don't have any Modbus ASCII device at hand, so we cannot give you a working example. But I'm adding this to my tutorial TODO list and schedule it for upcoming weeks.

Anyway, here you can find needed info, if you are keen to dive into the protocol parsing in ST by yourself. Remember - it works the same as ModbusRTU, but with different "formatting" so to speak.

Martin