Carlo Gavazzi WM15

Compatibility

Compatible with EpiSensor Edge over Modbus RTU

The WM15 is compatible with EpiSensor Edge over the RS-485 Modbus RTU port of its OS versions, read through a ZMB-31 Modbus Interface or a Gateway serial port. Carlo Gavazzi publishes the register map with FC03 and FC04, physical and Modicon addresses, data types, low-word-first word order and scale factors.

WM15 96 AV5 3 X OS (self-powered, with or without the PFB MID option) and WM15 96 AV5 3 H OS (auxiliary supply), using the WM15 communication protocol version 1.2 of 20 December 2019. OX versions have no communication port, and OM versions carry M-Bus, which this guide does not cover. Site check: read the identification code at 0x000B and compare the first voltage read with the display. Read-only monitoring: no writes to the password, system, CT ratio, serial port 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

The WM15 is a three-phase power analyser for switchboards: it measures voltage, current, power, power factor, frequency, THD up to the 15th harmonic and active, reactive and apparent energy through external 5 A current transformers, and shows them on a 128 × 64 dot backlit display with current bar graphs. Every version has a static output for pulses or an alarm; the OS versions add RS-485 Modbus RTU and the OM versions M-Bus. An optical port on the front takes Carlo Gavazzi's OptoProg for configuration.^2, 3

Order code

WM15 96 AV5 3, then supply X (self-powered, 415 V L-L) or H (auxiliary supply, 600 V L-L), then output OX (static output), OM (static output and M-Bus) or OS (static output and RS-485), then option X (class 1), PFB (MID, class B), X05 (class 0.5S) or a CN or KR display-language variant.^2, 3

Measuring inputs

Direct voltage connection: self-powered 120 to 240 V L-N, 208 to 415 V L-L; auxiliary-supply version 120 to 347 V L-N, 208 to 600 V L-L; MID 230 V L-N, 400 V L-L at 50 Hz. Current through CTs: 5 A rated, 6 A maximum, 10 mA start-up, CT ratio up to 2000. 45 to 65 Hz.²

Systems

Single-phase 2-wire, two-phase 3-wire, three-phase 3-wire and 4-wire, and the wild-leg four-wire delta. MID versions: three-phase with neutral, and three-phase without neutral (ARON).²

Accuracy

Active energy class 1 (EN 62053-21) and class B (EN 50470-3) on MID versions; class 0.5S (IEC 62053-22) with the 05 option. Reactive energy class 2 (EN 62053-23). Voltage ±0.5% of reading (±0.2% with the 05 option); current ±0.5% of reading from 0.05 In (±0.3%).²

RS-485

Modbus RTU on terminals 10 (A-), 11 (B+) and 12 (GND), with terminal 9 linked to B+ on the last device. Address 1 to 247 (default 1); 9.6, 19.2, 38.4, 57.6 or 115.2 kbit/s (default 9.6); no parity or even parity; 1 or 2 stop bits, with 1 fixed under even parity. Registers refresh every 100 ms or faster.^1, 2

Bus

1/5 unit load: up to 160 devices and 1000 m before a repeater. Terminate both ends: 120 Ω, ½ W at the master and the B+ to T link on the last WM15. AWG24 balanced pair with a third wire for GND, earthed only at the host.^1, 2

Digital output

One opto-mosfet output on terminals 7 and 8, for pulses (0.001 to 10 kWh per pulse, 30 or 100 ms) or an alarm; 100 mA maximum.^2, 3

Approvals

MID (2014/32/EU) on PFB versions; cULus approved (UL 61010); safety EN 61010-1; IEC/EN 61557-12 performance requirements for active power and energy.²

Housing

96 × 96 mm panel mounting, 280 g. Front IP51, terminals IP20; screw terminals 0.05 to 2.5 mm². Overvoltage category III, pollution degree 2.²

Environment

Operating -25 to +55 °C; storage -25 to +70 °C; relative humidity below 90% non-condensing at 40 °C.²

Interface

Documented measurements and integration boundaries for WM15.

• Addresses are physical word addresses sent in the frame: L1-N voltage is printed as Modicon 300001 and physical 0000h, and goes on the wire as 0x0000. FC03 and FC04 return the same values.
• INT32 values are two registers, low word first, with each word high byte first. Signed values use two's complement.
• L1-N, L2-N and L3-N voltage at 0x0000, 0x0002 and 0x0004; L1-L2, L2-L3 and L3-L1 at 0x0006, 0x0008 and 0x000A: INT32, volts × 10.
• L1, L2 and L3 current at 0x000C, 0x000E and 0x0010: INT32, amperes × 1000.
• L1 to L3 active power at 0x0012 to 0x0016 (W × 10), apparent power at 0x0018 to 0x001C (VA × 10) and reactive power at 0x001E to 0x0022 (var × 10): INT32.
• System values: V L-N at 0x0024 and V L-L at 0x0026 (V × 10), W at 0x0028, VA at 0x002A and var at 0x002C (× 10): INT32.
• Power factor L1, L2, L3 and system at 0x002E to 0x0031: one register each, INT16, PF × 1000, negative for exported active power. The same four with lead negative and lag positive are at 0x0072 to 0x0075.
• Phase sequence at 0x0032 (INT16: -1 is L1-L3-L2, 0 is L1-L2-L3) and frequency at 0x0033 (INT16, hertz × 10).
• Imported active energy kWh(+) TOT at 0x0034, imported reactive energy kvarh(+) TOT at 0x0036, exported kWh(-) TOT at 0x004E, exported kvarh(-) TOT at 0x0050 and apparent energy kVAh TOT at 0x0056: INT32, × 10. Per-phase kWh(+) at 0x0040, 0x0042 and 0x0044.
• Higher-resolution energy at 0x0500 (kWh(+) TOT), 0x0504 (kvarh(+) TOT), 0x051C (kWh(-) TOT) and 0x052C (kVAh TOT): four registers each, 64-bit, least significant word first, in Wh, varh and VAh. Frequency at 0x053C is INT32, hertz × 1000.
• System demand W sys DMD at 0x0038 and its maximum at 0x003A (W × 10); run hours at 0x005A (kWh+) and 0x005C (kWh-), INT32, hours × 100. Per-phase current and voltage THD at 0x0082 to 0x0096 (% × 100); 0x0088, 0x0090 and 0x0098 read 0.
• Identity: identification code at 0x000B (UINT16, read alone: 1680 is WM1596AV53XOSX, 1681 WM1596AV53XOSPFB, 1684 WM1596AV53HOSX); firmware at 0x0302 (major and minor in the high byte, revision in the low byte); serial number as ASCII at 0x5000 to 0x5006; production year at 0x5007; device state at 0x5012 (0 run, 1 fault, 2 configuration error).
• Keep each request to 20 registers or fewer: the protocol's frame tables limit a read to 1 to 14h registers, although its text mentions 125. A second copy of the measurements grouped by phase starts at 0x00F6.
• Password, system, CT ratio, serial-port and reset registers from 0x1000 to 0x4020 accept FC06 and FC10 writes; keep them out of a monitoring poll.

Setup

1. Identify the analyser

   Read the order code on the label. Modbus needs OS in the output position: OX has no communication port and OM has M-Bus. Note whether the supply position is X (self-powered) or H (auxiliary supply) and whether the option is PFB (MID).

2. Read the serial settings

   Open INFO from the main menu and read page 6, RS485, for the address, baud rate and parity. The defaults are address 1, 9.6 kbit/s, no parity and 1 stop bit. Enter the same values in the Edge serial client and leave the analyser's settings as they are.

3. Wire the RS-485 pair

   Connect A- to terminal 10, B+ to 11 and the common to GND on 12. Give each device on the bus its own address, link terminal 9 to B+ on the last WM15 only, and fit 120 Ω at the master end if it has no termination of its own.

4. Make two reads

   Read the identification code at 0x000B, one register on its own, and expect 1680, 1681 or 1684 for the OS versions. Then read L1-N voltage at 0x0000 for two registers and decode it low word first, as in the worked read below. Compare the result with page 21 of the measurement pages, L1-N V.

5. Add the points you need

   Add current, power, power factor and energy from Table 4.1-1, or the 64-bit energy counters from 0x0500 for watt-hour resolution. Keep FC06 and FC10 writes out of the polling configuration.

Common questions

Why does voltage read as millions of volts?

The client is taking the high word first. The WM15 sends INT32, UINT32 and UINT64 values with the least significant word first, and each word high byte first. Swap the two registers, then apply the scale: 2300 at 0x0000 is 230.0 V.¹

Which WM15 has Modbus?

Only the OS versions. The output position of the order code is OX for the static output alone, OM for the static output with M-Bus and OS for the static output with RS-485 Modbus RTU. The self-powered X and auxiliary-supply H versions are both available as OS.^2, 3

Why does frequency read 500?

The WM15 scales frequency at 0x0033 as hertz × 10, so 500 is 50.0 Hz. The high-resolution copy at 0x053C is INT32 in hertz × 1000. Do not reuse a frequency point from another Carlo Gavazzi meter without checking its scale in the WM15 protocol.¹

Why does exported energy stay at zero when one phase exports?

The WM15 sums the phase energies in every measuring interval and only the sign of the sum chooses the counter. With +2 kW, +2 kW and -3 kW on the three phases, kWh(+) increases by 1 kWh per hour and kWh(-) does not move. kWh(-) at 0x004E counts only when the whole system exports.²

Which energy registers give the best resolution?

The high-resolution table from 0x0500. Its energy counters are four registers each, 64-bit, least significant word first, in Wh, varh or VAh, against tenths of a kWh in the main table. The datasheet gives 0.001 kWh as the Modbus energy resolution.^1, 2

Can a WM15 PFB be used for billing?

The PFB versions are MID-certified, but only for total imported active energy (kWh TOT); exported, reactive, apparent and partial counters are not certified. This guide treats every value read over Modbus as monitoring data, not as a billing record.²