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 Jonathan,
do you have some touch screen from previous installation, or do you plan to purchase a new one? Generally speaking, the touch screens in industrial automation are equipped with PC (Pro-face for example) running custom HMI software, which communicates with PLC e.g. via Modbus. In this case, you can use Axon with no problem.

@boy-lenssen And I really recommend you to purchase the USB-RS485 converter. It is extremely handy for such debugging and it costs around $1 on eBay.

@martijn-hemeryck

You can measure the type of sensor quite easily with multimeter. Just connect the sensor to power supply and measure the voltage between OUT and GND. If the voltage changes from 0 to Vcc, then the sensor is PNP type. If not, switch the measurement to resistance. If the resistance changes from OL (open loop) to almost 0 ohm, then the sensor is NPN type.

Martin

Hello @jakub, the pin header of the Raspberry Pi inside of the Neuron is not accessible and there is no space inside of the Neuron for such additional devices.

Hello @cvrcejir,
unfortunately this is an error in the REST API, not the Evok's web interface. I forwarded this issue to the programmers and let you know once it is fixed.

Thank you for your patience,
Martin

Hi @ntd,
we would need some log files, namely /var/log/syslog and /var/log/kern.log from the time when the neurontcp service doesn't respond. Also post the output of these commands (execute them as root):

• dpkg -l | egrep "neuron|unipi|raspberrypi-kernel"
• /opt/unipi-bin/fwspi -i 0
• /opt/unipi-bin/fwspi -i 1
• /opt/unipi-bin/fwspi -i 2

You can post it here, or to the support@unipi.technology.

Hi @roberts_lando,
the problem probably lies in the dual gateway settings. The gateway should be set only on one interface. Same applies to the DNS settings, which I would put to the /etc/resolv.conf instead of here.

Best regards,
Martin

Hi @martijn-hemeryck,
some of the dependencies are quite tricky and we weren't able to handle the transitions between new package names gracefully. The repo is reachable, however the URL has to end with slash: https://repo.unipi.technology/debian/

Best regards,
Martin

Hello @HPC,
I am not sure if I understand the problem. Can you please specify what is connected to what on via which protocol / interface?

Thank you and have a nice day,
Martin

Hello @wzp, we don't have such thing, but you can find STEP models or CAD drawings for our products in the download section: https://kb.unipi.technology/en:files:products:00-start

Best regards,
Martin

Hi @lukas009,
it is the same issue. We will release Bullseye OS images once the support for all products is done. Looks like it could be next month.

Best regards,
Martin

Hi @knebb,
we are currently working on the Bullseye packages for the Unipi PLCs, but some important are still missing. The official release from our side will be after the official release of the RaspberryPI OS.

Best regards,
Martin

Hi @knebb,
you have verified, that the HW is working and returns correct value via standard tool. Checking and fixing your code is unfortunately beyond the scope of the free support.

Thank you for understanding and have a nice day,
Martin

Hi @knebb,
the firmware has been updated on our Knowledge Base as well: https://kb.unipi.technology/en:files:products:05-sensors:iaq

Martin

Hi @knebb,
yes, the firmware is indeed outdated. My colleague is going to fix this as soon as he gets back from holiday.

Thank you for your patience and have a nice day,
Martin

Hi @knebb,
here's a working mbpoll example reading a temperature:

root@mkudlacek:~# mbpoll 192.168.218.249 -a 1 -0 -1 -r 0 -c 2 -t 3:hex
mbpoll 1.4-25 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright © 2015-2019 Pascal JEAN, https://github.com/epsilonrt/mbpoll
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'mbpoll -w' for details.

Protocol configuration: Modbus TCP
Slave configuration...: address = [1]
                        start reference = 0, count = 2
Communication.........: 192.168.218.249, port 502, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, input register table

-- Polling slave 1...
[0]:    0x41AD
[1]:    0x05FD

The problem is probably in the slave address. You probably use "0" (modbus_set_slave(modbus, 0)), but it is "1".

Best regards,
Martin

@knebb Try running it on lower voltage, or put another resistor in series and do the recalculation in the software.

Martin

Hi @knebb,
can you please post the C code?

Thank you and have a nice day,
Martin