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Bo Jeanes 2022-09-09 12:15:22 +10:00
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README.md
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@ -4,77 +4,147 @@ A bridge between Modbus devices and MQTT.
It is early days, but the plan is:
* Support custom Modbus transports (Sungrow WiNet-S has been implemented)
* Support _setting_ holding registers over MQTT
* Support optional auto-configuration of Home Assistant entities, including using [MQTT Number](https://www.home-assistant.io/integrations/number.mqtt/) et al for holding registers, to allow setting the value.
* [x] Support custom Modbus transports (Sungrow WiNet-S has been implemented)
* Modbus RTU has not been tested because I don't have a serial Modbus device, but in principle it should work. Please let me know
* [x] Support reading input registers
* [x] Support reading holding registers
* [ ] Support _setting_ holding registers
* [ ] Support optional auto-configuration of Home Assistant entities, including using [MQTT Number](https://www.home-assistant.io/integrations/number.mqtt/) et al for holding registers, to allow setting the value.
* [ ] TLS MQTT connections
* [ ] ws:// and ws:// MQTT connections
NOTE: For the time being, this does not support MQTTv5.
## Installing
For now, use `cargo install` (Rust toolchain required). Soon, I will have release binaries attached to GitHub releases. In the future, there will also be Docker images made available for convenience.
## Running
Start the binary, passing in the URL to your MQTT server, including any credentials:
```sh-session
$ modbus-mqtt mqtt://$MQTT_HOST[:$MQTT_PORT]/[$CUSTOM_MODBUS_TOPIC]
```
The supported protocols are currently just `tcp://`/`mqtt://`, but with intent to support: `mqtts://`, `ssl://`/`tls://`, `ws://`, and `wss://`.
The default topic which ModbusMQTT monitors and to which it publishes is `modbus-mqtt`. You can vary that by changing the path portion of the MQTT URL.
Further, you can change other MQTT options by using query params, such as setting a custom client_id:
```sh
"mqtt://1.2.3.4/?client_id=$CUSTOM_CLIENT_ID"
```
For a full list of supported options, check [the MQTT client library's source code](https://github.com/bytebeamio/rumqtt/blob/c6dc1f7cfb26f6c1f676954a51b398708d49091a/rumqttc/src/lib.rs#L680-L768).
### Connecting to Modbus devices
To connect to a Modbus device, you need to post the connection details to MQTT under a topic of `$prefix/$connection_id/connect`. It is intended that such messages are marked as **retained** so that ModbusMQTT reconnects to your devices when it restarts.
For instance, a simple config might be:
```jsonc
// PUBLISH modbus-mqtt/solar-inverter/connect
{
"host": "10.10.10.219",
"proto": "tcp",
}
```
If the connection is successful, you will see the following message like the following sent to the MQTT server:
```jsonc
// modbus-mqtt/solar-inverter/state
"connected"
```
#### Full connection examples
All fields accepted (optional fields show defaults)
```jsonc
{
// Common fields
"address_offset": 0, // optional
"unit": 1, // optional, aliased to "slave"
// TCP:
"proto": "tcp",
"host": "1.2.3.4",
"port": 502, // optional
// RTU / Serial:
"proto": "rtu",
"tty": "/dev/ttyACM0",
"data_bits": "Eight", // optional (TODO: accept numeric and lowercase)
// valid: Five, Six, Seven, Eight
"stop_bits": "One", // optional (TODO: accept numeric and lowercase)
// valid: One, Two
"flow_control": "None", // optional (TODO: accept lowercase)
// valid: None, Software, Hardware
"parity": "None", // optional (TODO: accept lowercase)
// valid: None, Odd, Even
// Sungrow WiNet-S dongle
"proto": "winet-s",
"host": "1.2.3.4",
}
```
#### Monitoring registers
Post to `$MODBUS_MQTT_TOPIC/$CONNECTION_ID/$TYPE/$ADDRESS` where `$TYPE` is one of `input` or `holding` with the following payload (optional fields show defaults):
```jsonc
{
"name": null, // OPTIONAL - gives the register a name which is used in the register MQTT topics (must be a valid topic component)
"interval": "1m", // OPTIONAL - how often to update the registers value to MQTT
// e.g.: 3s (every 3 seconds)
// 2m (every 2 minutes)
// 1h (every 1 hour)
"swap_bytes": false, // OPTIONAL
"swap_words": false, // OPTIONAL
"type": "s16", // OPTIONAL
// valid: s8, s16, s32, s64 (signed)
// u8, u16, u32, u64 (unsigned)
// f32, f64 (floating point)
"scale": 0, // OPTIONAL - number in register will be multiplied by 10^(scale)
// e.g.: to turn kW into W, you would provide scale=3
// to turn W into kW, you would provide scale=-3
"offset": 0, // OPTIONAL - will be added to the final result (AFTER scaling)
// Additionally, "type" can be set to "array":
"type": "array",
"of": "u16" // The default array element is u16, but you can change it with the `of` field
}
```
Further, the `type` field can additionally be set to `"array"`, in which case, a `count` field must be provided. The array elements default to `"s16"` but can be overriden in the `"of"` field.
NOTE: this is likely to change such that there is always a `count` field (with default of 1) and if provided to be greater than 1, it will be interpreted to be an array of elements of the `type` specified.
There is some code to accept `"string"` type (with a required `length` field) but this is experimental and untested.
##### Register shorthand
When issuing the `connect` payload, you can optionally include `input` and/or `holding` fields as arrays containing the above register schema, as long as an `address` field is added. When present, these payloads will be replayed to the MQTT server as if the user had specified each register separately, as above.
This is a recommended way to specify connections, but the registers are broken out separately so that they can be dynamically added to too.
## Development
TODO: set up something like https://hub.docker.com/r/oitc/modbus-server to test with
## Similar projects
* https://github.com/Instathings/modbus2mqtt
* https://github.com/TenySmart/ModbusTCP2MQTT - Sungrow inverter specific
* https://github.com/bohdan-s/SunGather - Sungrow inverter specific
## Example connect config
```json
{
"host": "10.10.10.219",
"unit": 1,
"proto": "tcp",
"address_offset": -1,
"input": [{
"address": 5017,
"type": "u32",
"name": "dc_power",
"swap_words": false,
"period": "3s"
},
{
"address": 5008,
"type": "s16",
"name": "internal_temperature",
"period": "1m"
},
{
"address": 13008,
"type": "s32",
"name": "load_power",
"swap_words": false,
"period": "3s"
},
{
"address": 13010,
"type": "s32",
"name": "export_power",
"swap_words": false,
"period": "3s"
},
{
"address": 13022,
"name": "battery_power",
"period": "3s"
},
{
"address": 13023,
"name": "battery_level",
"period": "1m"
},
{
"address": 13024,
"name": "battery_health",
"period": "10m"
}],
"hold": [{
"address": 13058,
"name": "max_soc",
"period": "90s"
},
{
"address": 13059,
"name": "min_soc",
"period": "90s"
}]
}
```

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modbus-mqtt/examples/sungrow-sh5.0rs.json 100644
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@ -0,0 +1,62 @@
{
"host": "10.10.10.219",
"unit": 1,
"proto": "tcp",
"address_offset": -1,
"input": [
{
"address": 5017,
"type": "u32",
"name": "dc_power",
"swap_words": false,
"period": "3s"
},
{
"address": 5008,
"type": "s16",
"name": "internal_temperature",
"period": "1m"
},
{
"address": 13008,
"type": "s32",
"name": "load_power",
"swap_words": false,
"period": "3s"
},
{
"address": 13010,
"type": "s32",
"name": "export_power",
"swap_words": false,
"period": "3s"
},
{
"address": 13022,
"name": "battery_power",
"period": "3s"
},
{
"address": 13023,
"name": "battery_level",
"period": "1m"
},
{
"address": 13024,
"name": "battery_health",
"period": "10m"
}
],
"holding": [
{
"address": 13058,
"name": "max_soc",
"period": "90s"
},
{
"address": 13059,
"name": "min_soc",
"period": "90s"
}
]
}