Hi Everyone,
New here and attempting to help out my dad who has had a heat pump installed under the UK Eco Scheme.
He has a 12kW Samsung Gen 6 heat pump installed and I wanted to record its performance data directly from the heat pump as I am not looking for absolute values but the ability to trend the heat pump instrumentation so I can help him optimise his install. I am a chemical engineer but certainly not a hands on control engineer so looking for some help on setting up a Modbus interface from a PI4 installed with the latest EMON SD card and a Modbus RS485 to USB Adaptor from the EMON shop.
I have installed the SAMSUNG-ASHP-MIB19N modbus module in the heat pump:
I have used a Cat6 Ethernet cable run to the USB Modbus using two of the wires as you can see in the picture.
I have added the code to the Emon Config via EMONCMS and ensured there is no conflict of ttyUSB ports.
I get the following message repeatedly:
Blockquote
INFO SAMSUNG-ASHP-MIB19N Connecting to Modbus device=/dev/ttyUSB0 baud=9600 parity=even datatype=int
ERROR SAMSUNG-ASHP-MIB19N Could not connect to Modbus device
Any thoughts on what i am missing maybe i haven’t set something up on the MIB19N interface module or i have wired it incorrectly or ??
Thanks,
Gareth Richardson
Hi Gareth,
Have you tried swapping the wires connected to the A and B terminals on your USB interface?
You may (or may not!) need to connect the ground terminal to the Modbus module.
You said you have an MIB19N module, but the only docs I found are for an MIM-B19N.
The circuit board shown in the docs looks like the one in your picture, and if they are indeed
the same product, it looks as if you have the Modbus address set to 1.
The Modbus spec calls for even parity, which the line in the eror message you’re getting
says you’re using. However, it’s not uncommon to see no parity used.
MIM-B19N_Modbus_Interface_Module_GB_EN_221130-D01.pdf (417.5 KB)
Hi Bill,
Yes you are correct its not a MIB but MIM a typo on my part, thanks for replying!
I tried that today and to no effect. I then decided to double check the connection to the MIM-B19N unit and found one of the Ethernet connections had come off (probably happened when closed the heat pump up). Reconnecting this cable seemed to still come up with the same error.
I checked the LED lights on the MIM-B19N and the green light is flashing which according to the manual shows it is communicating with the heat pump, see below:
I checked the Config and the address is set to 1 so that seems to be correct.
When I relook at the Error code I wonder if it is the EmonPi not picking up the Modbus USB?
Have you tried using no parity vice even parity?
Samsung heat pump needs Even parity, see: https://docs.openenergymonitor.org/emonhub/emonhub-interfacers.html#samsung-ashp
Could you post the full emonhub.conf and emonhub.log
Could you SSH into the RasPi and post the output of
/dev/serial/by-id/ -la
This will list all the connected serial ports.
