Hello @lessmann,
the limit of how many devices can be connected to one RS485 line comes from the RS485 transceiver (the chip on the RS485 output) and on our PLCs it is 32. But be aware, that this is just a theoretical limit and the real limit depends on the current situation.

Second limit of the RS485 is the speed of the communication. Since RS485 is a half-duplex type of communication (master can speak only to one slave at a time), the more devices you have the lower speed of updates you will have.

If you have PLC with more RS485 ports, you can split the extensions into groups.

Best regards,
Martin

Hi @matt,
can you please verify how your USB device is enumerated in the system? Can you please post the dmesg output issued after connecting the device?

Thank you in advance and have a nice day,
Martin

@lessmann
You can use PLC as an ethernet extension. You can reconfigure the unipitcp service to listen on 0.0.0.0 instead of 127.0.0.1 thus making it publicly available. You can have one PLC running the program and acting as master.

Martin

Hi @beergeek,
can you please post what versions of our packages do you use?

dpkg -l | egrep "unipi|mervis|evok|axon|neuron"

And also what versions of firmware do you have in the boards:

sudo /opt/unipi/tools/fwspi -i 0
sudo /opt/unipi/tools/fwspi -i 1
sudo /opt/unipi/tools/fwspi -i 2

Thanks,
Martin

Hello @lessmann,
all of that looks like it will be manageble via our PLCs. What SW do you plan to use?

As for the dimmers: both of them looks like they could be used. Try looking for drivers which can be controlled over Modbus, 0-10V or 0-20mA. The DALI is quite complicated to setup right now, although we are working on a SW implementation which can be controlled over ModbusTCP. The DALI-enabled PLC is currently an Axon S605, lacking other IOs: https://www.unipi.technology/unipi-axon-s605-p179
You could try looking into DMX controlled LED drivers and use it together with OLA project: https://www.openlighting.org/ola/. But that will also require quite some amount of time to get it work. I can send you some proof-of-concept settings.

Best regards,
Martin

Hello @mike,
I am currently working on a very similar project - monitoring of a groundwater level and a independently controlled water pumps. There will be a web interface with information about exact water level in cm (up to 5m) with charted historical values and when the set threshold level will be exceeded an email and SMS will be sent to a set of addresses. All of that accesible via web interface.

If you are interested, please contact me on martin@modori.cz. We can continue in Czech language there.

Have a nice day,
Martin

Hello @mmcreativ,
there is no card inside of the PLC. It looks like the M205 isn't properly flashed or there is some HW error. Please, let's continue about the detail over email support@unipi.technology. Send us an email with this information:

• serial number of the PLC first
• photo or better yet a video of the top cover of the PLC with clear indication of the LED

Thank you and have a nice day,
Martin

Hello @rémi,
the Mervis can act as a ModbusTCP master, ModbusTCP slave, ModbusRTU master and ModbusRTU slave.

Best regards,
Martin

Hi @ckb,
if you use Mervis on UniPi 1.1, then you have practically no other option other than to use ModbusTCP. On the RaspberryPi you can create a Python script utilizing the pymodbus library and program the logic in a way the DIs and ROs are mapped to the coils and AO/AI are mapped to registers.

Best regards,
Martin

Hello @asunc,
absolutely no problem. The Axon is running a debootstraped arm64 Debian with added repository of our packages via which we publish fixes and new versions of our software.

Best regards,
Martin