Hi all,

I'm used to working with Codesys and I can't find my way fully around Mervis yet :)

So I am trying to read out some PPM CO2 readings from a Modbus RTU transmitter

• Datasheet: http://downloads.epluse.com/fileadmin/data/product/ee870/BA_EE870_e.pdf

• I'm trying to read out the CO2 fast parameter: Address: 29 + 30

It seems I can read out some values, but I have to combine them into a REAL, in Codesys I use UNION to combine both words (and swap them) into a REAL.

What is the easiest way to achieve this within Mervis?

Thank you.

Hi @tomas_hora ,

Thanks, I was able to get it up and running. It is working nicely together with the PI controller to controller the compressor speed of a small cooling set-up for an indoor farm testing unit.

Hi all,

I've been reading all possible documentation but it is still not clear what the correct and best/easiest way is to connect a Pt1000 probe to my NeuronL503 controlling it with Mervis.

• Pt1000: Datasheet

I've tried different things, but it never comes close to either the resistance value or temperature.

Any tips/ examples?

Thank you.

Kind regards,
Olivier

Ok, today I finally had some time to test this.

So I connected my device (as described above) and I receive the following message: "Modbus not running (or something similar)".

Any ideas on how I can debug/fix this?

Thank you.

OK, so I successfully ran the demo on the Unipi, so that means the the configuration is done? I can just leave the RS485 on "disabled? I don't need to include anything in my program for the RS485 to be "enabled", besides of course the added modbus device.

As there are 2 ports, A and B, do I need to make any specific changes when adding a "device"? Or is it enough the set the address on the slave device and Codesys?

And I found the proper way to add the registers, so I'll give it a try tomorrow.

Hi,

Me again; things are working out great and I'm very happy with the Unipi Neuron, so I keep on exploring more about it's functionality (and that of Codesys).

Next challenge, connect/communicate with a Modbus device. I'm trying to connect a CO2 sensor, which allows Modbus communication (I can also use analog output, but I have to connect multiple and then Modbus seems like a good solution).

Can someone point me in the right direction?

This is the datasheet/manual of the sensor: Manual

• Setting: Baudrate: 19200 // Stopbit: One // Parity: Even // Address: to be decided (5 dip-switches to set)

Modbus Map

I've already added the Modbus_COM and Modbus_Serial_Device, but no I have no idea on how to make the "link" with the Modbus Map.

Eternal thanks for all your help :)

Sharing the way I solved it, feel free to comment.

Thx!! It works perfectly :)

For those that would like to see the full code:

Hereby some screenshot on how I'm trying to read the AI, feel free to comment!

-> Line 27-30

-> Rank 3/4 (placeholder for conversion from input to what I need)

So this doesn't seem to work, any suggestions on putting the Unipi AI in the right mode (mA current, setAI21 and setAI22) AND on how to read the values (AI21 and AI22)

Thank you.

Hi,

I'm trying to connect some pH and EC "water-quality sensors" and I have some issues in working with the AIs.

More information about the sensors:

• The sensors are connected to a transmitter which has a display (so I can see the actual measured value) and it also has a 4-20mA (Active) output.

• 2 sensors (4-20mA) connected to AI2.1 and AI2.2, using the the 2 AGN next to each input.

Questions related to Neuron-Codesys

• What is the correct way to configure the output to read "current"? I've added the necessary channels for reading the input and also to select the AI mode. AI2.1 seems to be in "current mode - 3" but I'm doing the same thing for AI2.2 and it doesn't read anything.

• What values does it read? Because I'm seeing values like "10579" if I'm reading the analog input.

• The value I'm reading is not stable at all and jumps all over the place, 7852, 10813, 9681... all for the same measurement. Any clues what this could be?

Hopefully you can help as it is one of the last steps to get our set-up running :)

Thank you.