Huawei DTSU666-H

Compatibility

Compatible with EpiSensor Edge through the Huawei inverter or SmartLogger that reads it

The DTSU666-H's RS-485 Modbus RTU port belongs to the Huawei inverter or SmartLogger, which polls it at address 11 for export limitation and battery control. Edge reads that equipment instead: the SmartLogger3000 over its Modbus TCP interface, or the SUN2000 inverter over its own Modbus RTU communications pair, as the Huawei inverter and SmartLogger guides describe. Where Edge needs grid-point readings of its own, an EpiSensor ZEM with its own CTs measures the same connection point.

DTSU666-H (100 A/40 mA) and DTSU666-H 250 A/50 mA, as described in Huawei user manual EDOC1100020898 and quick guide Issue 03. Site check: confirm in the installed inverter's or SmartLogger's Modbus interface definition which power-meter values it publishes. Leave the sensor's RS-485 pair, address and serial settings on the inverter or SmartLogger; Edge is not a second client on that bus. The DTSU666-HW is a separate product.

Connect it with

• Modbus Interface ZMB-3X From €399 ex VAT Configure
• Wireless 3-Phase Electricity Monitor ZEM-65 From €625 ex VAT Configure
• Gateway ZGW-20 From €899 ex VAT Configure

Models

Specifications

Huawei's documents disagree on one point: the manual and quick guide list three-phase four-wire wiring only for the 100 A version and add three-wire for the 250 A version, while the current 100 A specification page lists 3P3W/3P4W. The wiring diagrams in the manual are the conservative reference.^1, 3, 4

Variants

DTSU666-H with three 100 A/40 mA CTs (0 to 100 A). DTSU666-H 250 A/50 mA with three 250 A/50 mA CTs (0 to 250 A).^3, 4

Voltage

Nominal 230/400 V AC. Phase voltage 176 to 288 V AC and line voltage 304 to 499 V AC on the 100 A specification page. Regulated working range 0.9 to 1.1 Un, extended 0.7 to 1.3 Un.^1, 4

Accuracy

Active energy class 1, 400 imp/kWh, connected via current transformers. The specification page lists current and voltage +/-0.5%, power and energy +/-1% and frequency +/-0.01 Hz. The supplied CTs are rated accuracy 0.5.^1, 4

Current transformers

Split-core. Ratio 2500:1 for 100 A and 5000:1 for 250 A, rated load 20 ohm. IA*, IA, IB*, IB, IC*, IC go to terminals 13, 14, 16, 17, 19 and 21; the CT arrow must match the direction in Huawei's diagram.^3, 4

RS-485

Modbus RTU on terminals 24 (A) and 25 (B), shielded twisted pair 0.20 to 1 mm². Default 9600 bit/s, no parity, one stop bit; nameplate address 11. The front-panel menu offers addresses 11 to 19, 4800 or 9600 bit/s, and none, even or odd parity.^3, 4

Power and data retention

Powered from the measured voltage, at most 1.5 W/6 VA on the voltage circuit. Data is kept for at least 10 years after power loss. A fuse and a thermistor protect each phase input inside the sensor.⁴

Mounting

Four modules on a 35 mm DIN rail, 72 x 100 x 65.5 mm. The manual gives at most 0.8 kg; the specification page gives 1.5 kg including cables.^1, 4

Environment

Operating -25 to +60 °C, limited working range -40 to +70 °C. Annual average humidity up to 75% in the manual; 5% to 95% non-condensing on the specification page.^1, 4

Standards

EN and IEC 61326-1, 61326-2-1, 61010-1 and 61010-2-1, plus EN 61000-3-2 and 61000-3-3 for EMC.⁴

Interface

Documented measurements and integration boundaries for DTSU666-H.

• Huawei publishes no Modbus register list for the DTSU666-H in its quick guide, user manual, datasheet or specification page, so this guide lists no register addresses.
• The display pages in the user manual show positive (import), negative (export) and combined active energy, total and per-phase active power, phase voltages, phase currents, total and per-phase power factor marked L or C, and frequency. These are display items, not a register map.
• Huawei states that combined active energy equals import minus export, and that displayed values are primary-side values. Energy is shown from 0 to 999999.9 kWh.
• The manual's product overview also mentions reactive power and four-quadrant energy, which do not appear in its display tables.
• Huawei describes the sensor as mainly for power control at the grid connection point. Its energy readings are for reference only and are not a basis for billing.

Setup

1. Identify the variant

   Read the front label: DTSU666-H with 100A/40mA, or DTSU666-H 250A/50mA. The rear nameplate shows type, current, class and the communication address. A DTSU666-HW is a different product.

2. Find the bus owner

   Trace the pair on terminals 24 (A) and 25 (B). Huawei connects it to the inverter's meter port in Smart Dongle networking or to a SmartLogger COM port in SmartLogger networking. If it is connected, the inverter or logger is polling it for export limitation or battery control; leave that wiring as it is.

3. Read the settings without changing them

   Step through the display pages with the arrow key to see the serial settings (for example n1-9600) and the address. Record them. Huawei says these must match the inverter, so changing them interrupts the inverter's control loop.

4. Check the CT orientation

   Compare per-phase active power on the display with the expected direction of flow. Huawei's troubleshooting table says negative Pa, Pb or Pc values point to a reversed CT or a mismatch between voltage and current phases.

5. Choose how Edge gets grid-point data

   Connect Edge to the inverter or SmartLogger, not to this bus: read the SmartLogger3000 over Modbus TCP or the inverter over its communications pair, as their guides describe. If Edge needs independent grid-point readings, fit an EpiSensor ZEM with its own CTs at the same point.

Common questions

Does the Chint DTSU666 register map apply to the DTSU666-H?

Huawei does not say so. Its specification page and datasheet name CHINT as the manufacturer and the nameplate carries the CHINT mark, but none of Huawei's DTSU666-H documents publishes a register list or points to Chint's map. Edge does not need one: it reads the grid-point values through the inverter or SmartLogger that polls the sensor.^1, 3, 4

Can Edge read the sensor while the inverter is connected to it?

Huawei connects the RS-485 pair to the inverter or SmartLogger, which uses the readings to limit export or control the battery, and tells installers to set the sensor's address, baud rate and parity to match the inverter. On a Modbus RTU serial line one client polls the devices, and Huawei does not describe adding a second reader. Edge therefore reads the inverter or SmartLogger over its own Modbus interface and takes the grid-point values from there, rather than joining this bus.^3, 4

What are the default serial settings and address?

Huawei gives 9600 bit/s, no parity and one stop bit, with address 11 on the nameplate. The front-panel menu offers addresses 11 to 19 and 4800 or 9600 bit/s; the manual's communication section also mentions 1200 and 2400 bit/s. The settings are protected by a password printed in the manual.^3, 4

Can the DTSU666-H be used for billing?

No. Huawei states that the sensor is mainly for power control at the grid connection point, that its energy readings are for reference only, and that electricity charges follow the meter provided by the grid company.⁴

Is the DTSU666-HW the same product?

No. Huawei lists the DTSU666-HW in the separate SmartPS-80AI-T0 datasheet with a 0 to 80 A range and 4800 to 115200 bit/s, alongside sensors from other manufacturers. This guide covers only the DTSU666-H and DTSU666-H 250 A/50 mA.⁵