Dobrý den pane Novotný,
ve zkratce - ano, je to možné a nepotřebujete na to ani Mervis.

Součástí operačního systému, který dáváte na kartu, je ModbusTCP server, přes který můžete ovládat veškeré vstupy-výstupy vyjma sběrnice 1-Wire. Tento server není typicky dostupný zvenčí ale je možné jej přenastavit tak, aby byl dostupný na portu TCP/502. Můžete tak k PLC jednotce, která se chová jako Modbus Slave, přistupovat z libovolné aplikace, která Modbus podporuje (například pomocí zmíněných Java knihoven). Seznam Modbusových registrů a coilů naleznete zde.

Druhou možností je použít API našeho softwaru Evok, kterým taktéž můžete ovládat celou jednotku a to včetně zařízení na sběrnici 1-Wire.

Tutoriály na tyto způsoby komunikace budeme připravovat v následujících týdnech.

S pozdravem,
Martin Kudláček

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.

Dobrý den Dalibore,
toto je velmi jednoduché. V MervisIDE přidáte na PLC "Serverový kanál" a nastavíte protokol na ModbusTCP. Přidáte serverové zařízení, nastavíte mu IP adresu, port a modbusovou adresu, na které bude přístupné. V detailu zařízení pak namapujete registry a coily na příslušné proměnné. K proměnným pak přistupujete přes síť z libovolného Modbus Master zařízení / programu.

Místo ModbusTCP je možné použít i ModbusRTU, kde nakonfigurujete příslušný RS485 port a nastavíte modbusovou adresu.

Nemám ověřenou funkcionalitu na starém IDE (2.0.x), ale v novém, které bude začátkem září je toto plně funkční.

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 @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

Hello @stevenhendrickx,
I'll start from the end - the RaspberryPi running an InfluxDB. I can only guess - and correct me if I am wrong - but you have only SD card with the Raspbian in your RaspberryPi, right? The SD cards are quite fragile regarding the number of data you can write on them. That's the reason why we switch the filesystem in MervisOS to read-only. So generally, running a database on the SD card is not-so-good idea.

Now to the part how to access Mervis variables from outside. Currently the most straightforward method is via Modbus. If you haven't use Modbus before, please take a look on the protocol itself: physical layers, addressing, datatypes,... The Wikipedia article is a good (a bit too complicated) start.
Then check our tutorial how to setup ModbusTCP server (slave) in Mervis: https://kb.unipi.technology/en:sw:01-mervis:setting-modbus-server-hidden
And to put it together check this Python Gist how to poll data from ModbusRTU slave into InfluxDB: https://gist.github.com/sansal54/bea2526ab8e968351a85db3410cc9f65

There's a lot of information you need to grasp from the beginning to get it working. Feel free to ask more.

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 @LubomirMaron, you can always flash the SD card with the clean image. Then do the licensing and then upload the solution.

Hello @LubomirMaron,
if "Configure the Unipi Module" fails to connect to the PLC, that means the PLC is not reachable over ethernet. Try reattaching to the PLC.

Tip: this can happen when you switch Profiles. Reattaching usually helps.

Best regards,
Martin

Dobrý den @linex,
na co nejspíš narážíte je pomalost vyčítaných hodnot. Ta souvisí s funkcí autogen. Zkuste si prosím projít tento tutorial: https://kb.unipi.technology/cs:sw:01-mervis:autogen-hidden

S pozdravem,
Martin Kudláček

Hello @LubomirMaron,
deploying of the solution doesn't affect the configuration of the IOs. You need to "Configure the Unipi Module": https://kb.unipi.technology/en:sw:01-mervis:unipi-configure-module-hidden

Best regards,
Martin

Hello @wicked,
my colleague meant something like this:

Then you will have RS485 on the Unipi 1.1 and you can connect to the Weintek over DB9. It will act as a additional serial port to the one exposed as RJ11 connector.

Best regards,
Martin

Hello @wzp, create a output variable by the same name as the function.

Best regards,
Martin

Hello @rtatibouet,
the RS485 and RS232 are completely different buses.

The RS485 is differential and doesn't need the GND, since the logic levels are based on the voltage difference between A and B terminal

The RS232 is not differential and the TX / RX logic levels are based on the voltages between TX and GND and RX and GND.

Best regards,
Martin

Hello @FabioIT, we have updated the tutorial on measuring the resistance: https://kb.unipi.technology/en:automation:02-glossary:analog-inputs-hidden#measuring_resistance

Hello @Stoeffel,
the Evok 2.3.0 with support for xG18 has been released. You can proceed with the apt update && apt install evok.

Using the xG18 is definitely more stable. Each sensor has its own dedicated port and the powering of the sensors is parasitic, which ensures that the sensor will lose the power and "reset" itself after each reading. Another great advantage is that you don't need to configure the IDs of the sensors, so replacement is very quick.

Best regards,
Martin

Hello @Stoeffel,
the xG18 is not yet supported in the current version of Evok. We will publish the new version of Evok today or tommorow. I'll let you know, once it is out.

Thank you for understanding and have a nice day,
Martin