Why does this template only have tariff 1 and tariff 2, not tariff 3 and 4?

Tariff 1 and tariff 2 (active and reactive) are defined directly in the official Eastron multi-tariff protocol and can be read reliably. Tariff 3 and 4 registers appear in some firmware but are not guaranteed across SDM630-MT revisions, so they are intentionally left out to avoid reading meaningless values. If you have confirmed T3/T4 addresses for your exact firmware, they can be added later.

The tariff counters do not switch between T1 and T2. What is wrong?

Tariff switching is driven by the meter's internal real-time clock and tariff schedule, not by Modbus. Set the clock and the T1/T2 time windows in the SDM630-MT front-panel menu. ModbusCloud only reads the resulting counters.

I see wildly wrong numbers like 3.4e38. Byte order problem?

Yes. Float32 registers can be decoded ABCD, CDAB, BADC, or DCBA depending on the converter. This template uses CDAB to match the standard Eastron SDM630 template. If your gateway expects a different order, swap the byte order in ModbusCloud device settings.

Voltages read correctly but currents are zero. What is wrong?

This is almost always a missing CT connection on the meter. Check that the current transformers are clamped in the right orientation and wired to the correct meter terminals. The SDM630-MT shows live currents on its display, which is the fastest way to verify hardware before suspecting Modbus.

Free Modbus template: Eastron SDM630-MT (Multi-Tariff)

Name: Eastron SDM630-MT (Multi-Tariff)
Brand: Eastron
SKU: b2e7c1a4-3d9f-4e6a-9c12-8f5a2d7b4e30

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Free Modbus template: Eastron SDM630-MT (Multi-Tariff) | ModbusCloud

Registers (41)

41 read / 0 write

Name	Address	Function	Type	Unit	Access
Voltage L1	0	FC04	float32	V	R
Voltage L2	2	FC04	float32	V	R
Voltage L3	4	FC04	float32	V	R
Current L1	6	FC04	float32	A	R
Current L2	8	FC04	float32	A	R
Current L3	10	FC04	float32	A	R
Power L1	12	FC04	float32	W	R
Power L2	14	FC04	float32	W	R
Power L3	16	FC04	float32	W	R
Volt Amps L1	18	FC04	float32	VA	R
Volt Amps L2	20	FC04	float32	VA	R
Volt Amps L3	22	FC04	float32	VA	R
Reactive Power L1	24	FC04	float32	var	R
Reactive Power L2	26	FC04	float32	var	R
Reactive Power L3	28	FC04	float32	var	R
Power Factor L1 Power factor L1 (cos phi)	30	FC04	float32		R
Power Factor L2 Power factor L2 (cos phi)	32	FC04	float32		R
Power Factor L3 Power factor L3 (cos phi)	34	FC04	float32		R
Average L/N Voltage	42	FC04	float32	V	R
Average Line Current	46	FC04	float32	A	R
Sum of Line Currents	48	FC04	float32	A	R
Total System Power	52	FC04	float32	W	R
Total System VA	56	FC04	float32	VA	R
Total System var	60	FC04	float32	var	R
Total System Power Factor Total power factor (cos phi)	62	FC04	float32		R
Frequency	70	FC04	float32	Hz	R
Total Import Energy	72	FC04	float32	kWh	R
Total Export Energy	74	FC04	float32	kWh	R
Total Import Reactive	76	FC04	float32	kVArh	R
Total Export Reactive	78	FC04	float32	kVArh	R
Line 1 to Line 2 Voltage	200	FC04	float32	V	R
Line 2 to Line 3 Voltage	202	FC04	float32	V	R
Line 3 to Line 1 Voltage	204	FC04	float32	V	R
Average Line to Line Voltage	206	FC04	float32	V	R
Neutral Current	224	FC04	float32	A	R
Total Energy Total active energy (import + export)	342	FC04	float32	kWh	R
Total Reactive Energy Total reactive energy (import + export)	344	FC04	float32	kVArh	R
Tariff 1 Active Energy Cumulative active energy on tariff 1 (T1), switched by the meter RTC. Official Eastron multi-tariff register.	4876	FC04	float32	kWh	R
Tariff 2 Active Energy Cumulative active energy on tariff 2 (T2), switched by the meter RTC. Official Eastron multi-tariff register.	4878	FC04	float32	kWh	R
Tariff 1 Reactive Energy Cumulative reactive energy on tariff 1 (T1).	4900	FC04	float32	kVArh	R
Tariff 2 Reactive Energy Cumulative reactive energy on tariff 2 (T2).	4902	FC04	float32	kVArh	R

Eastron SDM630-MT (Multi-Tariff)

Overview

Key readings

Use cases

Installation

Things to watch for

Registers (41)

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