modbus to USB adaptor installation

[paultanner]

I have followed the config guidance and tried this

[[MBUS]]
    Type = EmonHubMBUSInterfacer
    [[[init_settings]]]
        device = /dev/ttyAMA0
        baud = 2400
    [[[runtimesettings]]]
        pubchannels = ToEmonCMS,
        read_interval = 10
        validate_checksum = False
        nodename = MBUS
        [[[[meters]]]]
            [[[[[sontex]]]]]
                address = 1
                type = sontex531

The device (from emon shop) is plugged into a USB port on a pi and the A port of this is connected to the MBUS port of my Sontex using a piece of telephone wire.

The error I get is

MainThread Device communication error - check settings                         

There may be some other config to do, maybe of the Sontex?
Any suggestions please.

[glynhudson]

Hi Paul, have you checked to see see what mbus address the sontex is set to? Trystan has made a script to check the address and change the address if needed: https://github.com/emoncms/usefulscripts/tree/master/mbus

[paultanner]

@glyn sent me this https://github.com/emoncms/usefulscripts/tree/master/mbus and I also saw that I was using a serial port not /dev/ttyUSB0.
I modified the check script to try all 254 possible addresses but the meter did not respond on any of them.
Any further suggestions?

[glyn]

@glyn sent me this https://github.com/emoncms/usefulscripts/tree/master/mbus and I also saw that I was using a serial port not /dev/ttyUSB0. I modified the check script to try all 254 possible addresses but the meter did not respond on any of them. Any further suggestions?

Did you mean @glynhudson ?

[paultanner]

Yes @glynhudson. Forgot to check before submitting.
I have since found that the sontex is set to 2400 baud and address 0.
Am trying to find out how to change that as the sontex doc is unclear.

[glynhudson]

You can change the Sontex Mbus address using this script: https://github.com/emoncms/usefulscripts/blob/master/mbus/mbus_set_address.py

[paultanner]

The problem is that the meter does not respond at all. The device address is set to zero. I have asked Sontex if I can change that setting another way but have yet to hear back from them.

[paultanner]

I have now set the meter address to 1. Still no response.

[glynhudson]

It sounds like you're doing everything correct! Mbus on Sontex has just worked for me assuming the address was set correctly. I'll ask @TrystanLea to take a look, he's the mbus expert, and he wrote the above scripts to set the address and read from the meter.

[paultanner]

I'm wondering what other settings might be needed? baud rate looks OK (2400). pi is connected on /dev/ttyUSB0.

[TrystanLea]

Hello Paul, I think some/all Sontex meters require a power supply for the MBUS to work, is yours powered by an AC power supply? could you take a picture of the connections on the sontex?

[paultanner]

This is battery-powered. The only connections at the moment are 2 temp sensors, one flow meter and the mbus. This is the type that has the mbus module factory-installed.

[paultanner]

Yes. Stockshed (Sontex dist) confirm that power is required. Now I need to know how to do that. I can run AC power to it but do not have the necessary info to hook it up. I gather that m-bus needs +/- 15v to operate. Sounds like I should have got the mains-powered version as that might have this other supply rail?

[paultanner]

Correction: apparently the normal approach is for the data logger to power the m-bus, not the meter (as there may be multiple data sources on the m-bus). Looks like I need to adapt the OEM "m-bus to usb adaptor" to add the power circuit. Any suggestions on that? I'm happy to do some breadboarding/ soldering.

[TrystanLea]

Hello Paul. The MBUS reader already has an integrated power supply for the MBUS part, but it doesn't power the heat meter. That requires a separate AC power supply for the Sontex itself.

[paultanner]

Thx Trystan. When I got the Sontex there was a choice of battery or mains power. I chose battery and the meter is working. Are you saying that the mains option powers the m-bus whereas the battery does not?