Contactor,circuit breaker,sensor,Encoder,PLC,Converter
Discontinued (discontinued in China on 2014-12-31). No new original units available from manufacturer. Only second-hand or surplus stock parts on market. METSEPM53 series is the preferred replacement.
Model Code Explanation
PM750: High-end multifunction power monitor of PM700 series
MG: Modbus RS485 communication version, equipped with digital I/O, harmonic measurement and min/max value logging
Core Functions
- True RMS full electrical measurement: 3-phase / single-phase voltage, current, active/reactive/apparent power, power factor, frequency; phase-wise & total active energy kWh, reactive energy kvarh, demand / peak demand, maximum & minimum value recording.
- Power quality: Total Harmonic Distortion (THD), harmonic analysis up to 15th order, sampling rate 32 samples per cycle.
- I/O Interface: 2 digital inputs (DI), 1 static digital output (DO). DO configurable for pulse output (energy pulse), alarm output or remote control. DI for status acquisition or demand synchronization trigger.
- Alarm function: 15 groups of user-defined threshold alarms (overvoltage, undervoltage, overcurrent, power limit violation, etc.), local indication + alarm report via communication.
- Communication: RS485, Modbus RTU protocol, up to 19200bps, compatible with PLC, SCADA and energy management systems.
- Display: Backlit LCD, 6-line display, panel cutout mounting.
Key Electrical Specifications
| Item | Specifications |
| Measuring Voltage | Line-to-line: 10～480V AC; Phase-to-neutral:10～277V AC, 45~65Hz |
| Current Input | CT secondary 0.005～6A (5A/1A CT both supported) |
| Power Supply | AC:115~415V; DC:125~250V; Power consumption ≤5VA |
| Accuracy | Current ±0.4%; Voltage ±0.3%; Power ±0.5%; Active energy Class 0.5S (IEC62053-22) |
| DI | 12~36VDC, nominal 24VDC, 2.5kV isolation |
| DO | Static transistor output, supports pulse / alarm mode |
Typical Application
LV/MV switchgear, factory power distribution room, building power distribution, computer room incoming cabinet. Used for power monitoring, energy consumption statistics, power quality monitoring and status acquisition; commonly used as spare parts for legacy project retrofits.
OEM Replacement Models (Key)
PM750MG → METSEPM5330 (RS485 Modbus); For Ethernet version: METSEPM5340 (Modbus TCP)
PM53 series is upgraded replacement for PM750, full & enhanced function coverage, identical panel cutout size for direct mounting. Modbus register addresses are incompatible, reconfiguration required. High-end alternative: PM8240/PM8243.
Common Troubleshooting Checklist
- No current / reversed current reading: CT S1/S2 reversed; CT secondary shorting link not removed; CT ratio not configured in meter.
- Modbus communication failure: Missing termination resistor, A/B wire reversal, mismatched address/baud rate; unstable meter supply.
- DO no action: Verify DO mode configuration (pulse/alarm) and polarity of external circuit.
- Abnormal harmonic reading: Loose wiring, insufficient PT/CT accuracy, heavy distortion on load side.
Supplementary Notes
Cutout dimension: 92×92mm, panel flush mounting
Standards: IEC 62053, ANSI C12.20; compatible with 3P3L /3P4L / single-phase systems
Second-hand spare note: LCD backlight aging, damaged RS485 transceiver chip, parameter loss due to internal battery depletion.
- PM750MG Modbus RTU Register Summary (Holding Registers, 4xxxx, 16bit; Energy values as 32bit, occupies 2 consecutive registers)
Protocol Notes: Modbus RTU, register starts at 40001 (Schneider standard). Some software uses 0-based addressing (40000), pay attention to offset. For float /32bit unsigned integer, high word first. Energy registers come with multiplier register; readings must be multiplied by multiplier factor.
Firmware version: V3.050 (common firmware for PM700 series)
| Modbus Address(4xxxx) | Data Type | Name | Description |
| 40001 | UINT16 | V1 Phase Voltage | Phase voltage, multiplier register 40013 |
| 40002 | UINT16 | V2 Phase Voltage | |
| 40003 | UINT16 | V3 Phase Voltage | |
| 40004 | UINT16 | V12 Line Voltage | |
| 40005 | UINT16 | V23 Line Voltage | |
| 40006 | UINT16 | V31 Line Voltage | |
| 40007 | UINT16 | I1 Phase A Current | Current, multiplier register 40014 |
| 40008 | UINT16 | I2 Phase B Current | |
| 40009 | UINT16 | I3 Phase C Current | |
| 40010 | UINT16 | Frequency Hz | |
| 40011 | UINT16 | Total Active Power kW | Power multiplier 40015 |
| 40012 | UINT16 | Total Reactive Power kvar | |
| 40013 | UINT16 | Voltage Multiplier (10^n) | e.g. value=2 → ×100 |
| 40014 | UINT16 | Current Multiplier (10^n) | |
| 40015 | UINT16 | Power Multiplier (10^n) | |
| 40016 | UINT16 | Total Power Factor | Range 0~1000, divide by 1000 |
| 4,002,040,021 | UINT32 | Total Active Energy kWh | 40020=High word,40021=Low word; multiplier 40108 |
| 4,002,240,023 | UINT32 | Total Reactive Energy kvarh | |
| 4,002,440,025 | UINT32 | Total Apparent Energy kVAh | |
| 40030 | UINT16 | Phase A THD | Current total harmonic distortion |
| 40031 | UINT16 | Phase B THD | |
| 40032 | UINT16 | Phase C THD | |
| 40040 | UINT16 | DI Status | Bit0=DI1，Bit1=DI2 |
| 40041 | UINT16 | DO Status | Bit0=DO1 |
| 40045 | UINT16 | Alarm Status Word | Alarm mask |
| 40108 | UINT16 | Energy Multiplier (10^n) | Energy reading ×10^n, Important! |
Energy Calculation Example: 40020=0012, 40021=ABCD; 40108=2 → 0x0012ABCD ×10² = 1254860 ×100 = 125486000 Wh = 125486 kWh
Harmonics: 1~15th harmonic magnitudes, registers start at 40050, per-phase harmonic amplitude.
Communication Basic Parameters (PM750MG)
Protocol: Modbus RTU
Baud rate: 2400/9600/19200
Parity: None / Odd / Even; Stop bit:1
Slave address: 1~247
RS485 Terminals: A, B; 120Ω termination resistor at bus end
- PM750MG vs METSEPM5330 Function & Wiring Migration Comparison Table
| Item | PM750MG (Old Meter) | METSEPM5330 (Replacement Meter) | Migration Notes |
| Cutout Size | 92×92mm | 92×92mm | Identical panel cutout, direct mounting |
| Power Supply | AC115~415V / DC125~250V | AC100~415V / DC110~250V | Power circuit can be reused directly |
| Voltage Input | 10~480V line voltage | 10~480V line voltage | PT secondary wiring unchanged; support 3P3L/3P4L |
| Current Input | CT secondary 0.005~6A | CT secondary 0.005~6A | CT S1/S2 wiring unchanged, CT ratio must be reconfigured on new meter |
| DI | 2DI (24VDC) | 2DI (24VDC) | External DI wiring can be kept |
| DO | 1-channel static transistor output | 2-channel relay DO | ⚠️Major difference! PM750MG uses transistor DO; PM5330 is dry contact relay. Original DO pulse/alarm circuit needs redesign, higher load capacity. |
| Harmonic Measurement | Up to 15th harmonic | Up to 31st harmonic | PM5330 enhanced power quality capability |
| Alarm Groups | 15 groups | 35 groups | Alarm logic can be migrated, register addresses for alarms are fully different |
| Communication | RS485 Modbus RTU | RS485 Modbus RTU | Physical A/B wiring unchanged. Register mapping is fully incompatible! PLC/SCADA program must be rewritten, old register addresses cannot be reused. |
| Energy Tariff | Single tariff | 4 tariffs | Support time-of-use metering |
| Accuracy | Active energy Class 0.5S | Active energy Class 0.5S | Same accuracy class |
| Data Logging | Max & Min values | Max & Min + Event log | PM5330 supports event logging |
Retrofit Risk Checklist (Mandatory for Site Replacement)
- DO circuit modification: PM750MG transistor output cannot drive heavy load. PM5330 uses relay. If original DO sends pulse to acquisition module, verify dry-contact pulse compatibility with acquisition device.
- Host software program reconstruction: Register address, data arrangement and multiplier logic are all different. All tags for PLC / KingView / ForceControl / SCADA must be reconfigured; old program cannot be copied directly.
- Parameter re-entry: CT ratio, PT ratio, system type (3P3L/3P4L), alarm threshold, Modbus address and baud rate all require manual setup. Parameters from PM750MG cannot be imported into PM5330.
- Real-time clock: PM750MG internal battery loses parameters on power loss; PM5330 retains parameters after power loss, only clock resets.
III. Terminal Wiring Comparison
PM750MG Terminal Layout
- L1 L2 L3 N Voltage Input
- CT1 CT2 CT3 Current Input
- Power Terminals
- DI1 DI2 COM
- DO+ DO(Transistor)
- RS485 A B
METSEPM5330 Terminal Layout
- L1 L2 L3 N Voltage
- CT1 CT2 CT3 Current
- Power
- DI1 DI2 COM
- DO1, DO2 (Relay, independent dry contact)
- RS485 A B
Voltage, current, DI and RS485 cables may remain untouched; DO wiring must be rewired.
- On-site Replacement Procedure
- Power off and confirm safety; record original PM750MG parameters (CT/PT ratio, system type, alarm settings, communication parameters).
- Remove old meter, keep voltage, CT, DI and RS485 cables.
- Install METSEPM5330, connect voltage, CT, DI and RS485; rework DO wiring separately.
- Power up, configure CT/PT ratio, system wiring type, Modbus address, baud rate and alarm thresholds.
- Verify real-time measurements: voltage, current, power; confirm CT polarity is correct.
- Modify PLC / SCADA Modbus program, debug communication.
- Compare accumulated energy readings, run continuous test to verify metering accuracy.
Schneider PowerLogic PM700 Series Full Model List (All discontinued)
Series basics: 92×92mm panel mounting, True RMS measurement, THD, min/max logging. Suffix Definition
MG: With RS485 Modbus RTU communication
CA: North American ANSI version (rarely used in China; Chinese projects prefer models without CA suffix)
P: 2-channel solid-state pulse output
Full Model List
- PM700 Base model, no communication, no pulse output
- PM700CA North American base version
- PM700MG Base measurement + RS485 Modbus
- PM700MGCA NA version + Modbus
- PM700P Base model + 2 solid-state pulse outputs, no communication
- PM700PCA NA version with pulse output
- PM700PMG Base + pulse output + RS485 Modbus
- PM700PMGCA NA version, pulse + Modbus
- PM710 Base measurement + RS485 Modbus, no DI/DO
- PM710CA NA PM710
- PM710MG Mainstream domestic PM710 (Modbus)
- PM710MGCA NA PM710MG
- PM750 Top tier, RS485 Modbus, 2DI+1DO, alarm function
- PM750MG Most common domestic model (target model, Modbus version)
- PM750CA NA PM750
- PM750MGCA NA PM750MG
Comparison of 4 Core Models (Common for China Projects)
| Model | Core Configuration | Application |
| PM700 | Basic electrical +THD/min-max, No comms, no pulse | Local display only, no SCADA connection |
| PM700P | Basic electrical +THD, 2 pulse outputs, No comms | Energy pulse acquisition, no network |
| PM710MG | Basic electrical +THD, RS485 Modbus, No DI/DO | Remote power acquisition, no status points needed |
| PM750MG | Full electrical +THD+15th harmonic, RS485 Modbus, 2DI+1DO+threshold alarms | Power monitoring, remote status acquisition, alarm output (largest installed base in China) |
Discontinuation & Replacement Summary
APAC discontinuation date: 2015-04-30; Americas:2015-08-30. No new original production, only surplus / second-hand spare parts.
PM700 / PM700P / PM710 → METSEPM51xx (PM5100 series)
PM750 / PM750MG → METSEPM53xx (METSEPM5330 RS485; METSEPM5340 Ethernet TCP)
Supplementary Remarks
- This series does NOT have PM720/PM730/PM740. Many documents are misleading. PM700 series only has four base platforms: PM700, PM700P, PM710, PM750.
- CA suffix = North American ANSI variant, differs in wiring logic & voltage rating. Avoid CA-suffix spares for China retrofits.
- All models share identical 92×92mm cutout and panel appearance; only internal I/O and communication hardware differ.
