[RFC] refactor meter opcode definitions

[andig]

Currently, a lot of code is used to define meter opcodes (query snips). This could be greatly reduced by specifying standard "opcodes" and define its mapping register per meter. The approach could use e.g. simple structures like this:

iec61850  := map[string]string{
	"VolLocPhsA":       "L1 Voltage (V)",
	"VolLocPhsB":       "L2 Voltage (V)",
	"VolLocPhsC":       "L3 Voltage (V)",
	"AmpLocPhsA":       "L1 Current (A)",
	"AmpLocPhsB":       "L2 Current (A)",
	"AmpLocPhsC":       "L3 Current (A)",
	"WLocPhsA":         "L1 Power (W)",
	"WLocPhsB":         "L2 Power (W)",
	"WLocPhsC":         "L3 Power (W)",
	"AngLocPhsA":       "L1 Cosphi",
	"AngLocPhsB":       "L2 Cosphi",
	"AngLocPhsC":       "L3 Cosphi",
	"TotkWhImportPhsA": "L1 Import (kWh)",
	"TotkWhImportPhsB": "L2 Import (kWh)",
	"TotkWhImportPhsC": "L3 Import (kWh)",
	"TotkWhImport":     "Total Import (kWh)",
	"TotkWhExportPhsA": "L1 Export (kWh)",
	"TotkWhExportPhsB": "L2 Export (kWh)",
	"TotkWhExportPhsC": "L3 Export (kWh)",
	"TotkWhExport":     "Total Export (kWh)",
	"ThdVolPhsA":       "L1 Voltage to neutral THD (%)",
	"ThdVolPhsB":       "L2 Voltage to neutral THD (%)",
	"ThdVolPhsC":       "L3 Voltage to neutral THD (%)",
	"ThdVol":           "Average voltage to neutral THD (%)",
	"Freq":             "Frequency of supply voltages",
}
fmt.Println(iec61850)

Meter definitions would look like this:

sdm := map[string]int{
	"L1Voltage":   0x0000,
	"L2Voltage":   0x0002,
	"L3Voltage":   0x0004,
	"L1Current":   0x0006,
	"L2Current":   0x0008,
	"L3Current":   0x000A,
	"L1Power":     0x000C,
	"L2Power":     0x000E,
	"L3Power":     0x0010,
	"L1Import":    0x015a,
	"L2Import":    0x015c,
	"L3Import":    0x015e,
	"TotalImport": 0x0048,
	"L1Export":    0x0160,
	"L2Export":    0x0162,
	"L3Export":    0x0164,
	"TotalExport": 0x004a,
	"L1Cosphi":    0x001e,
	"L2Cosphi":    0x0020,
	"L3Cosphi":    0x0022,
	// "L1THDCurrent":         0x00F0,
	// "L2THDCurrent":         0x00F2,
	// "L3THDCurrent":         0x00F4,
	// "AvgTHDCurrent":        0x00Fa,
	"L1THDVoltageNeutral":  0x00ea,
	"L2THDVoltageNeutral":  0x00ec,
	"L3THDVoltageNeutral":  0x00ee,
	"AvgTHDVoltageNeutral": 0x00F8,
	"Frequency":            0x0046,
}
fmt.Println(sdm)

janitza := map[string]int{
	"L1Voltage":   0x4A38,
	"L2Voltage":   0x4A3A,
	"L3Voltage":   0x4A3C,
	"L1Current":   0x4A44,
	"L2Current":   0x4A46,
	"L3Current":   0x4A48,
	"L1Power":     0x4A4C,
	"L2Power":     0x4A4E,
	"L3Power":     0x4A50,
	"L1Import":    0x4A76,
	"L2Import":    0x4A78,
	"L3Import":    0x4A7A,
	"TotalImport": 0x4A7C,
	"L1Export":    0x4A7E,
	"L2Export":    0x4A80,
	"L3Export":    0x4A82,
	"TotalExport": 0x4A84,
	"L1Cosphi":    0x4A64,
	"L2Cosphi":    0x4A66,
	"L3Cosphi":    0x4A68,
}
fmt.Println(janitza)

Defining all QuerySnips per meter (Produce())would then be a simple matter of iterating over the struct.

I'd prefer to combine this with a single naming regime for opcodes. UI and APIs currently use IEC61850 (e.g. VolLocPhsA ), code internally relies on more speaking names like L1Voltage. My preference would be the latter for UI, API and source code.

If this is only applied to the new sdm630 daemon this could be considered a non-breaking change. Opinions welcome.

[andig]

Partial implementation in #52

[andig]

Full implementation in #69