DSMR/ESMR telegram to MQTT pusher

Sketch to read data from the P1 port of DSMR compliant electricity meters. It verifies the CRC16 of the telegram, greatly reducing the chance for errors.

The Rx on a DSMR compliant meter is an open collector output, which means that the current must be supplied by the receiving device and that the resulting output signal is inverted. In the sketch, the Rx is inverted using SoftwareSerial, so no hardware inversion is needed.

Graphs

To get nice graphs out of it, check my Metergrafiekjes docker configuration!

Compatibility & Hardware

Written for and tested on Wemos D1 mini v2, should work on any ESP8266 derived device.

The RTS needs 5V input to be triggered. This means that if you use an ESP or other microcontroller that works on 3.3V, you will need a level shifter or an RTL inverter to control it.

I have designed a PCB to handle the hardware-level interfacing with the P1 port, contact me if you want one or check out my Pwuts/Metertrekker repo.

How to use

Assuming you have the repository files:

1. copy settings.example.h -> settings.h
2. adjust device specific firmware settings, setting defaults (if you need to)
3. upload to your device
4. power up device, connect to its access point
5. go to captive settings portal
6. configure
7. restart device
8. connect device to meter

If you are planning to also use the Metergrafiekjes docker configuration, please set that up first, so that when configuring the Metertrekker, you will know the address of the MQTT server.

WiFi portal

The WiFi portal will start automatically when no configuration is present or when the device cannot connect to the configured WiFi network. The portal will also start when no telegram can be retrieved within timeout. This means you can start the portal by disconnecting the device from the P1 port.

Note for DSMR <4.0 users

Your meter does not include a CRC in its telegrams. This sketch will attempt to filter out large errors by pair-checking the brackets in the telegram, but keep in mind that you may get faulty data, since the firmware will not be able to compensate for most transmission errors.

Dependencies

• CRC16 library retrieved from vinmenn/Crc16 on Github
• ESP-WiFiSettings library
• arduino-mqtt library

Developing / contributing

If you want to work on, derive from, or tinker with this firmware or its functionality, the following snippet may come in handy:

/* Valid telegram for testing purposes */
char bufferIn[768] = "/ISK5\\2M550E-1012\r\n"
                     "\r\n"
                     "1-3:0.2.8(50)\r\n"
                     "0-0:1.0.0(190827155511S)\r\n"
                     "0-0:96.1.1(4D455445525F53455249414C235F484558)\r\n"
                     "1-0:1.8.1(000057.460*kWh)\r\n"
                     "1-0:1.8.2(000037.300*kWh)\r\n"
                     "1-0:2.8.1(000000.000*kWh)\r\n"
                     "1-0:2.8.2(000000.000*kWh)\r\n"
                     "0-0:96.14.0(0002)\r\n"
                     "1-0:1.7.0(00.498*kW)\r\n"
                     "1-0:2.7.0(00.000*kW)\r\n"
                     "0-0:96.7.21(00008)\r\n"
                     "0-0:96.7.9(00002)\r\n"
                     "1-0:99.97.0()\r\n"
                     "1-0:32.32.0(00005)\r\n"
                     "1-0:32.36.0(00001)\r\n"
                     "0-0:96.13.0()\r\n"
                     "1-0:32.7.0(235.4*V)\r\n"
                     "1-0:31.7.0(002*A)\r\n"
                     "1-0:21.7.0(00.454*kW)\r\n"
                     "1-0:22.7.0(00.000*kW)\r\n"
                     "0-1:24.1.0(003)\r\n"
                     "0-1:96.1.0(4D455445525F53455249414C235F484558)\r\n"
                     "0-1:24.2.1(190827155507S)(00004.380*m3)\r\n"
                     "!";
int readLength = strlen(bufferIn);
char receivedCRC[5] = "ECDF";

This telegram is ESMR 5.0 compliant and the given CRC16 is valid for this telegram.