I found out a bit about it: Electrically it is an UART interface where the counter is fed through the RX pin. In image top right pin is TX out and lower left pin is RX in. The remaning 2 Pins are GND. Protocolwise the device seems to use m-bus, for which a linux library is available.
Hi @Phunkafizer, i try to connect directly to the 4-pin interface since i only have the SCR+ Interface but not the modbus-adapter. do you have more information if this is possible and if so how/what voltage and protocol? seems there is very little information around for this 4-pin connector
unfortunately I do not have any information about the SCR protocol, my gas meter was shipped in m-bus configuration. Voltage is 5 V, but a simple UART interface won’t work as the meter is supplied via the TX pin. You need a current amplifier (e. g. MOSFET) between the UART interface and the meter.
Wow, also tried to find something about that protocol some time ago, but was not able to find it.
Do you have a SCM communication module and just want to pick up the data between it and the meter, or do you want to built an own communication module which will read out the meter?
For the modbus variant I did the latter with a battery powered ESP8266 module.
Ideally one (me) could just plug an ESP to the 4-pin port of the actual meter and read the meters impulses, avoiding any Com-Modul, is that what you built? would be perfect
I had the SCR module already preinstalled but guess it wont be too easy, when looking into the docs in detail. I guess its not that straight forward to build a SCR+ Adapter for an ESP or a RPi … at least for me If someone else feel like, here are some more insights I have so far
TX : You can send requests to the Meter by changing to input current
Imin = 0.5 mA (idle mode. The Meter waits for a command)
• Inom = 4 mA (while the Meter reads out the mechanical rollers)
• Imax = 30 mA (inrush current. See also chapter 2.1.2), kind of start the meter filling up a capacitor… most probably the most tricky part
RX : you can read from the meter with 300baud in standard EDIS 1995, OBIS 2005 or OMS 2.0.0 (depending on the type of meter you have), i guess at least OBIS 2005 is standardized in iec62056-21.
I already have a working device which implements the physical layer, at least for the m-bus variant. I assume that the physical layer is identical, as the meter can be configured by the energyprovider in SCM or m-bus. If you are able to built firmware for a ESP8266 and flash it you could give it a try with one of my module, see attachment.
I see, that you are also based in Fuerth as I am.
After I more or less unsuccessfully tried to read the BK-G4 AT via infrared and optical recognition, I’m also interested in your module.
I do have experieces with ESP32 and ESP8266 (mainly with Tasmota as OS).
Maybe we can also physically connect to get a working solution.
If you are interested, you can also send me a PM.