WAGO 879-3000

Compatibility

Compatible with EpiSensor Edge over Modbus RTU

The 879-3000 is compatible with EpiSensor Edge over its RS-485 Modbus RTU port, read through a ZMB-31 Modbus Interface or a Gateway serial port. WAGO publishes the FC03 register map with hexadecimal addresses, register lengths, units and Float ABCD data types, and its own write examples confirm the address convention.

WAGO 879-3000 (4PU) and 879-3020 (4PS), direct connection 5(65) A, and 879-3040 (2PU CT) with a programmed CT ratio, using the Appendix 3 register map in operating instructions version 022024V1.8. Site check: confirm that register 0x4026 reads 1 (Standard) and compare the first voltage read with the display before adding points. Read-only monitoring: no writes to the ID, baud rate, parity, tariff, CT ratio, data type or reset registers.

Connect it with

• Modbus Interface ZMB-3X From €399 ex VAT Configure
• Gateway ZGW-20 From €899 ex VAT Configure

Models

Specifications

Item numbers

879-3000 (4PU) and 879-3020 (4PS), direct connection, 65 A. 879-3040 (2PU CT), CT connection.²

Voltage

Nominal 3 × 230/400 V AC; operating 3 × 230/400 V ±20%; 45 to 60 Hz in the manual, 50 Hz on the instruction sheet. Three-phase four-wire, three-wire delta, open delta (Aron, IT networks only) or single-phase connection.^1, 2

Current

4PU and 4PS: Ib 5 A, Imax 65 A, operating from 0.4% of Ib. 2PU CT: Ib 1 A, Imax 5 A, with a CT primary of 1 to 9999 A on /1 or 5 to 9995 A on /5, changeable at most seven times.¹

Accuracy and approval

Class B (1%) to EN 50470-1/3. The manual reproduces MID, UKCA and CE declarations of conformity for the 4PU/4PS and the 2PU CT.¹

RS-485

Modbus RTU with 16-bit CRC on terminals 7 (A) and 8 (B, shared with M-Bus -). Modbus ID 1 to 247 (default 1). Default 9600 bit/s, 8 data bits, no parity, 1 stop bit; 1200 to 115200 bit/s and even or odd parity can be set.¹

Bus

Up to 60 meters per bus and up to 1000 m in the manual, depending on the converter, baud rate and installation. For a test through a serial converter, the manual asks for a 120 ohm, 0.25 W resistor across terminals 7 and 8 at the meter.¹

Other interfaces

M-Bus on 8 and 9 (default 2400 bit/s, even parity, primary address 0). Two S0 open-collector outputs on 4 and 6 with 5 as common, up to 27 V DC and 100 mA. 230 V tariff input on 10 and 11. Bluetooth BLE 4.2.¹

Housing and terminals

4PU/4PS: 72 mm wide, 92 mm high without cover (140 mm with), 63 mm deep, 0.34 kg. 2PU CT: 36 mm wide, 97 mm high, 0.2 kg. Main terminals take 0.75 to 25 mm² fine-stranded conductors; auxiliary terminals 0.2 to 4 mm².¹

Environment

Operating -40 to +70 °C; humidity up to 75% in operation and 95% in storage. IP51 front, IP20 connections, protection class II; indoor use in an enclosure (M1, E2).¹

Interface

Documented measurements and integration boundaries for 879-3000.

• Addresses are hexadecimal PDU addresses: 0x5002 is sent as 50 02 (decimal 20482). Read every point with FC03. WAGO's own write example 01 06 4003 000A sends register 4003 exactly as printed.
• Data type at 0x4026: one register, 1 = Standard, 2 = Integer. The map gives every measurement as Float ABCD, so confirm it reads 1 before decoding; the manual does not describe the Integer format.
• Identity: serial number at 0x4000 (two registers, hex), meter code at 0x4002 (0x1111 4PU, 0x1112 4PS, 0x1113 2PU CT), software version at 0x4007 (Float ABCD) and CT ratio at 0x401F (two registers, hex, 9995005 = 9995/5).
• L1, L2 and L3 voltage at 0x5002, 0x5004 and 0x5006: two registers, Float ABCD (high word first), V. Line voltages L1-L2, L1-L3 and L2-L3 at 0x5032, 0x5034 and 0x5036.
• Frequency at 0x5008 (Hz). L1, L2 and L3 current at 0x500C, 0x500E and 0x5010: two registers, Float ABCD, A.
• Total active power at 0x5012, then L1 to L3 at 0x5014, 0x5016 and 0x5018: Float ABCD, kW. Total reactive power at 0x501A (kvar), total apparent power at 0x5022 (kVA) and total power factor at 0x502A, each followed by its L1 to L3 values.
• Total active energy at 0x6000, active energy import at 0x600C and active energy export at 0x6018: Float ABCD, kWh, each followed by T1, T2 and L1 to L3 counters. T3 and T4 active energy follow from 0x604B.
• Total, import and export reactive energy at 0x6024, 0x6030 and 0x603C (kvarh), with four-quadrant reactive energy from 0x6063 and the resettable day register at 0x6049.
• The combination code at 0x400F sets total active energy: 1 import only, 2 export only, 3 import + export, 4 import - export. Read import at 0x600C and export at 0x6018 when a site can export.
• The map marks 0x5000 Voltage and 0x500A Current with an asterisk it does not explain. Use the per-phase registers instead.
• On the 2PU CT, forward and reverse active energy for the ex-factory 5/5 ratio and for each of up to seven CT changes are kept from 0x6100 to 0x6196.
• Writable registers include the Modbus ID (0x4003), baud rate (0x4004), parity (0x4011), tariff (0x6048), CT ratio (0x401F), data type (0x4026) and counter resets. Keep FC06 and FC16 out of a monitoring poll.

Setup

1. Identify the meter

   Read the item number from the side label: 879-3000 (4PU), 879-3020 (4PS) or 879-3040 (2PU CT). Note the software version on the display, and for the 2PU CT the CT ratio set on the meter.

2. Read the serial settings without changing them

   The settings menu shows the Modbus ID, baud rate and parity; it asks for the four-digit password (0000 unless the installer changed it). The defaults are ID 1, 9600 bit/s, 8 data bits, no parity and 1 stop bit. Enter the same values in the Edge serial client or the ZMB-31.

3. Wire the RS-485 pair

   Connect A to terminal 7 and B to terminal 8 and give each meter on the bus its own Modbus ID. Terminal 8 is also M-Bus negative, so keep the M-Bus pair on 8 and 9 separate from the Modbus wiring.

4. Make two reads

   Read 0x4026 for one register and expect 1 (Standard). Then send FC03 to 0x5002 for two registers and decode the Float32 high word first, as in the worked read below. Compare the result with L1 voltage on the display.

5. Add the points you need

   Add current, power and energy registers from the same appendix. Log import and export energy separately when the site can export, and keep FC06 and FC16 writes out of the polling configuration.

Common questions

Is 5002 a decimal register number?

No. WAGO prints the 879-3000 addresses in hexadecimal, which is why the map has entries such as 400B and 501A. Send 0x5002, decimal 20482, as the PDU address. A tool that asks for one-based register numbers needs 20483.¹

Why does a float register read as nonsense?

Check two things. The words must be taken high word first (Float ABCD): 43 66 00 00 at 0x5002 is 230.0 V. And register 0x4026 must read 1 (Standard): the manual documents a write that sets it to 2 (Integer) but does not describe that format, so the Float ABCD map no longer applies.¹

Which energy register measures consumption?

Active energy import at 0x600C counts consumption and active energy export at 0x6018 counts export, each with T1, T2 and per-phase counters after it. Total active energy at 0x6000 follows the combination code at 0x400F, so compare it with the display before using it.¹

Can the CT ratio on the 879-3040 be changed later?

At most seven times. Each change is recorded as a CT history entry with its energy readings, kept in registers 0x6100 to 0x6196, and the seventh setting is final. Read the active ratio at 0x401F and never write it from a monitoring client.¹

Does a 32-bit float energy counter lose resolution?

Yes, gradually. A Float32 holds about seven significant digits: above about 131,000 kWh the counter moves in steps of about 0.016 kWh, and above about 1,050,000 kWh in steps of 0.125 kWh. The display itself has 6+3 digits and rolls over from 999999.999 to zero. Store each value as received and calculate consumption over intervals.¹

Does the map include writable registers?

Yes. The manual documents FC06 and FC16 writes for the Modbus ID, baud rate, S0 rate and pulse settings, parity, tariff, CT ratio, data type, display settings and counter resets. A monitoring configuration should read with FC03 only.¹