[WIP] Better RTU meter detection (if supported by device)

meters/device.go

@@ -31,7 +31,7 @@ type Device interface {
 
 	// Probe tests if a basic register, typically VoltageL1, can be read.
 	// It requires that the client has the correct device id applied.
-	Probe(client modbus.Client) (MeasurementResult, error)
+	Probe(client modbus.Client) (bool, error)
 
 	// Query retrieves all registers that the device supports.
 	// It requires that the client has the correct device id applied.

meters/rs485/abb.go

@@ -67,7 +67,7 @@ func (p *ABBProducer) Type() string {
 
 // Description implements Producer interface
 func (p *ABBProducer) Description() string {
-	return "ABB A/B-Series meters"
+	return "ABB A/B-Series"
 }
 
 // wrapTransform validates if reading result is undefined and returns NaN in that case

meters/rs485/dzg.go

@@ -59,7 +59,7 @@ func (p *DZGProducer) Type() string {
 
 // Description implements Producer interface
 func (p *DZGProducer) Description() string {
-	return "DZG Metering GmbH DVH4013 meters"
+	return "DZG Metering GmbH DVH4013"
 }
 
 func (p *DZGProducer) snip(iec Measurement, scaler ...float64) Operation {

meters/rs485/janitza.go

@@ -51,7 +51,7 @@ func (p *JanitzaProducer) Type() string {
 
 // Description implements Producer interface
 func (p *JanitzaProducer) Description() string {
-	return "Janitza B-Series meters"
+	return "Janitza B-Series"
 }
 
 func (p *JanitzaProducer) snip(iec Measurement) Operation {

meters/rs485/mpm3pm.go

@@ -55,7 +55,7 @@ func (p *MPM3MPProducer) Type() string {
 
 // Description implements Producer interface
 func (p *MPM3MPProducer) Description() string {
-	return "Bernecker Engineering MPM3PM meters"
+	return "Bernecker Engineering MPM3PM"
 }
 
 func (p *MPM3MPProducer) snip(iec Measurement, readlen uint16, transform RTUTransform, scaler ...float64) Operation {

meters/rs485/producer.go

@@ -32,6 +32,11 @@ type Producer interface {
 	Probe() Operation
 }
 
+// Identificator implements device recognition logic
+type Identificator interface {
+	Identify(bytes []byte) bool
+}
+
 // Opcodes map measurements to physical registers
 type Opcodes map[meters.Measurement]uint16
 

meters/rs485/rs485.go

@@ -57,15 +57,9 @@ func (d *rs485) Descriptor() meters.DeviceDescriptor {
 	}
 }
 
-func (d *rs485) query(client modbus.Client, op Operation) (res meters.MeasurementResult, err error) {
-	var bytes []byte
-
+func (d *rs485) rawQuery(client modbus.Client, op Operation) (bytes []byte, err error) {
 	if op.ReadLen == 0 {
-		return res, fmt.Errorf("invalid meter operation %v", op)
-	}
-
-	if op.Transform == nil {
-		return res, fmt.Errorf("transformation not defined: %v", op)
+		return bytes, fmt.Errorf("invalid meter operation %v", op)
 	}
 
 	switch op.FuncCode {
@@ -74,11 +68,24 @@ func (d *rs485) query(client modbus.Client, op Operation) (res meters.Measuremen
 	case ReadInputReg:
 		bytes, err = client.ReadInputRegisters(op.OpCode, op.ReadLen)
 	default:
-		return res, fmt.Errorf("unknown function code %d", op.FuncCode)
+		return bytes, fmt.Errorf("unknown function code %d", op.FuncCode)
 	}
 
 	if err != nil {
-		return res, errors.Wrap(err, "read failed")
+		return bytes, errors.Wrap(err, "read failed")
+	}
+
+	return bytes, nil
+}
+
+func (d *rs485) query(client modbus.Client, op Operation) (res meters.MeasurementResult, err error) {
+	if op.Transform == nil {
+		return res, fmt.Errorf("transformation not defined: %v", op)
+	}
+
+	bytes, err := d.rawQuery(client, op)
+	if err != nil {
+		return res, err
 	}
 
 	res = meters.MeasurementResult{
@@ -91,15 +98,31 @@ func (d *rs485) query(client modbus.Client, op Operation) (res meters.Measuremen
 }
 
 // Probe is called by the handler after preparing the bus by setting the device id
-func (d *rs485) Probe(client modbus.Client) (res meters.MeasurementResult, err error) {
+func (d *rs485) Probe(client modbus.Client) (res bool, err error) {
 	op := d.producer.Probe()
 
-	res, err = d.query(client, op)
+	// use specific identificator for devices that are able to recognize
+	// themselves reliably
+	if idf, ok := d.producer.(Identificator); ok {
+		bytes, err := d.rawQuery(client, op)
+		if err != nil {
+			return false, err
+		}
+
+		match := idf.Identify(bytes)
+		return match, nil
+	}
+
+	// use default validator looking for 110/230V
+	measurement, err := d.query(client, op)
 	if err != nil {
-		return res, err
+		return false, err
 	}
 
-	return res, nil
+	v := validator{[]float64{110, 230}}
+	match := v.validate(measurement.Value)
+
+	return match, nil
 }
 
 // Query is called by the handler after preparing the bus by setting the device id and waiting for rate limit

meters/rs485/sbc.go

@@ -11,12 +11,15 @@ const (
 )
 
 type SBCProducer struct {
+	typ    string
+	phases int
 	Opcodes
 }
 
 func NewSBCProducer() Producer {
 	/**
 	 * Opcodes for Saia Burgess ALE3
+	 * https://www.sbc-support.com/uploads/tx_srcproducts/26-527_ENG_DS_EnergyMeter-ALE3-with-Modbus_01.pdf
 	 * http://datenblatt.stark-elektronik.de/saia_burgess/DE_DS_Energymeter-ALE3-with-Modbus.pdf
 	 */
 	ops := Opcodes{
@@ -46,7 +49,11 @@ func NewSBCProducer() Producer {
 		Power:         51, // scaler 100
 		ReactivePower: 52, // scaler 100
 	}
-	return &SBCProducer{Opcodes: ops}
+	return &SBCProducer{
+		typ:     "ALE3", // assume ALE3
+		phases:  3,      // assume 3 phase device
+		Opcodes: ops,
+	}
 }
 
 // Type implements Producer interface
@@ -56,7 +63,7 @@ func (p *SBCProducer) Type() string {
 
 // Description implements Producer interface
 func (p *SBCProducer) Description() string {
-	return "Saia Burgess Controls ALE3 meters"
+	return "Saia Burgess " + p.typ
 }
 
 // snip creates modbus operation
@@ -93,8 +100,35 @@ func (p *SBCProducer) snip32(iec Measurement, scaler ...float64) Operation {
 	return snip
 }
 
+// Identify implements Identifier interface
+func (p *SBCProducer) Identify(bytes []byte) bool {
+	if len(bytes) < 4 {
+		return false
+	}
+
+	switch string(bytes[:4]) {
+	case "ALD1":
+		// single phase
+		p.phases = 1
+	case "ALE3", "AWE3":
+		// three phase direct/ converter
+		p.phases = 3
+	default:
+		return false
+	}
+
+	p.typ = string(bytes[:4])
+	return true
+}
+
+// Probe implements Producer interface
 func (p *SBCProducer) Probe() Operation {
-	return p.snip16(VoltageL1)
+	// return p.snip16(VoltageL1)
+	return Operation{
+		FuncCode: ReadHoldingReg,
+		OpCode:   6,
+		ReadLen:  4,
+	}
 }
 
 // Produce implements Producer interface

meters/rs485/sdm.go

@@ -70,7 +70,7 @@ func (p *SDMProducer) Type() string {
 }
 
 func (p *SDMProducer) Description() string {
-	return "Eastron SDM meters"
+	return "Eastron SDM"
 }
 
 func (p *SDMProducer) snip(iec Measurement) Operation {

meters/rs485/validator.go

@@ -0,0 +1,16 @@
+package rs485
+
+// validator checks if value is in range of reference values
+type validator struct {
+	refs []float64
+}
+
+func (v validator) validate(f float64) bool {
+	tolerance := 0.1 // 10%
+	for _, ref := range v.refs {
+		if f >= (1-tolerance)*ref && f <= (1+tolerance)*ref {
+			return true
+		}
+	}
+	return false
+}