Add basic Modbus support

README.md

@@ -33,6 +33,7 @@ to any number of different targets, such as databases or MQTT.
 * Supports _**multiple different power sensors**_
   * [IotaWatt](http://iotawatt.com/)
   * [Shelly](https://www.shelly.com/) (both Gen 1 and Gen 2)
+  * Generic Modbus sensors (limited support)
 * Supports _**virtual power sensors**_
   * A virtual power sensor gets its values from other configured sensors, enabling the user to calculate the total 
     power usage of three-phase devices or three-phase mains power

examples/config.sample.full.yml

@@ -31,6 +31,7 @@ circuits:
           - Vägg vardagsrum
           - Vägg kök
           - Vägg arbetsrum
+      clamp: positive # Don't allow negative values
   # A IotaWatt main circuit, phase A/L1
   - name: Main L1
     type: main
@@ -133,6 +134,18 @@ circuits:
         type: gen2-em
         meter: 0
         phase: a
+  # A circuit with a Modbus sensor
+  - name: Inverter/chargers
+    type: circuit
+    sensor:
+      type: modbus
+      modbus:
+        address: 10.112.4.250
+        port: 502
+        unit: 100
+        register: 866
+        type: int16
+      clamp: positive
 
 #
 # Characteristics. Characteristics mean voltage and frequency, and potentially other non-power related readings.

package.json

@@ -33,6 +33,7 @@
   "dependencies": {
     "@influxdata/influxdb-client": "^1.33.2",
     "axios": "^1.6.0",
+    "modbus-serial": "^8.0.16",
     "mqtt": "^5.1.2",
     "slugify": "^1.6.6",
     "winston": "^3.11.0",

src/config.ts

@@ -7,6 +7,7 @@ import {
   getCharacteristicsSensorData as getIotawattCharacteristicsSensorData,
   getSensorData as getIotawattSensorData,
 } from './sensor/iotawatt'
+import { getSensorData as getModbusSensorData } from './sensor/modbus'
 import { getSensorData as getVirtualSensorData } from './sensor/virtual'
 import { getSensorData as getUnmeteredSensorData } from './sensor/unmetered'
 import {
@@ -153,6 +154,9 @@ export const resolveAndValidateConfig = (config: Config): Config => {
       case SensorType.Iotawatt:
         circuit.sensor.pollFunc = getIotawattSensorData
         break
+      case SensorType.Modbus:
+        circuit.sensor.pollFunc = getModbusSensorData
+        break
       case SensorType.Virtual:
         circuit.sensor.pollFunc = getVirtualSensorData
         break

src/eachwatt.ts

@@ -9,7 +9,8 @@ import { WebSocketPublisherImpl } from './publisher/websocket'
 import { PublisherType } from './publisher'
 import { pollCharacteristicsSensors } from './characteristics'
 import { createLogger } from './logger'
-import { setRequestTimeout } from './http/client'
+import { setRequestTimeout as setHttpRequestTimeout } from './http/client'
+import { setRequestTimeout as setModbusRequestTimeout } from './modbus/client'
 
 // Set up a signal handler, so we can exit on Ctrl + C when run from Docker
 process.on('SIGINT', () => {
@@ -52,10 +53,16 @@ const mainPollerFunc = async (config: Config) => {
   // Poll characteristics sensors
   const characteristicsSensorData = await pollCharacteristicsSensors(now, config.characteristics)
 
-  // Round all numbers to one decimal point
+  // Post-process power sensor data
   for (const data of powerSensorData) {
     if (data.power !== undefined) {
+      // Round all numbers to one decimal point
       data.power = Number(data.power.toFixed(1))
+
+      // Optionally clamp values
+      if (data.circuit.sensor.clamp === 'positive') {
+        data.power = Math.max(0, data.power)
+      }
     }
   }
 
@@ -101,10 +108,12 @@ const mainPollerFunc = async (config: Config) => {
     publisherImpl: webSocketServer,
   })
 
-  // Adjust the HTTP timeout to be half that of the polling interval
+  // Adjust request timeouts to be half that of the polling interval
   const pollingInterval = config.settings.pollingInterval
   logger.info(`Polling sensors with interval ${pollingInterval} milliseconds`)
-  setRequestTimeout((pollingInterval as number) / 2)
+  const timeoutMs = (pollingInterval as number) / 2
+  setHttpRequestTimeout(timeoutMs)
+  setModbusRequestTimeout(timeoutMs)
 
   // Start polling sensors
   await mainPollerFunc(config)