SATEC PM135

Power meter

The PM135 is SATEC's compact three-phase power meter for a 92 × 92 mm or 4 inch round panel cut-out, measuring through 5 A or 1 A current transformers. The PM135P measures voltage, current, power and frequency, the PM135E adds energy counters, tariffs and logging, and the PM135EH adds harmonic analysis. Every model has an RS-485 port, COM1, running Modbus RTU, and the ETH expansion module adds a Modbus TCP server on port 502. SATEC numbers its registers in decimal and sends 32-bit values low word first, in volts, amps and kilowatts whose resolution depends on a setting in the meter.

SATEC PM135E panel power meter, front view
  • Modbus RTU
  • Modbus TCP

Power meter

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Compatibility

Compatible with EpiSensor Edge over Modbus RTU or Modbus TCP

The PM135 is compatible with EpiSensor Edge over Modbus RTU on its built-in COM1 RS-485 port, read through a ZMB-31 Modbus Interface or a Gateway serial port, and over Modbus TCP on port 502 when the ETH module is fitted. SATEC publishes the register map with decimal addresses, data types, low-word-first word order, units and worked conversions.

PM135P, PM135E and PM135EH, using the PM135 Modbus reference guide BG0515 Rev. A2 with installation manual BG0518 Rev. A4. Energy registers need a PM135E or PM135EH. Site check: read the device resolution at register 2390 and compare the first voltage read with the display. PROFIBUS, DNP3, IEC 60870-5 and SATEC ASCII are outside this guide. Read-only monitoring: no writes to setup, password, relay or reset registers.

Connect it with

Route into Edge

For a meter in a switchboard where a wireless link avoids running a data cable back to the Gateway

  • Modbus
  • Wireless
  • Edge
  • Platforms
Power meter
Interface
Gateway
Edge
Output
PM135PM135 COM1 RS-485 terminal
ZMB-31Modbus RTU to the EpiSensor wireless network
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeModbus client + register map
Customer platformMQTT · API · files
Modbus RTU · RS-485
EpiSensor wireless
Runs locally
Optional onward data
Wire the two-wire RS-485 pair and shield from the removable three-pin COM1 connector to the ZMB-31, match the meter's Modbus address, baud rate and data format, and read the measurement registers with FC03. If a SCADA master already polls COM1, agree the change with its owner first. The customer-platform output is optional; Edge remains the local system of record.

When the Gateway sits near the meter, or several meters share one wired RS-485 bus

  • Modbus
  • Edge
  • Platforms
Power meter
Interface
Gateway
Edge
Output
PM135PM135 COM1 RS-485 terminal
Isolated serial interfaceApproved RS-485-to-host adapter
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeEdge Modbus client
Customer platformMQTT · API · files
Modbus RTU · RS-485
Isolated serial
Runs locally
Optional onward data
Give each meter its own Modbus address, use the same baud rate and data format on every meter and in the Edge serial client, and fit the 120 to 500 Ω, ½ W end resistors shown in SATEC's wiring diagram. Read with FC03 at the decimal addresses from the reference guide. The customer-platform output is optional; Edge remains the local system of record.

When the meter has the ETH expansion module, or a 12DIOR module with its Ethernet port

  • Modbus
  • Edge
  • Platforms
Power meter
Interface
Gateway
Edge
Output
PM135PM135 ETH module RJ45
Protected EthernetSegmented LAN
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeEdge Modbus TCP client
Customer platformMQTT · API · files
Modbus TCP
Protected Ethernet
Runs locally
Optional onward data
The meter runs a permanent Modbus TCP server on port 502 at its configured IP address, factory set to 192.168.0.203. It accepts two simultaneous Modbus TCP connections, so Edge takes one; leave the other for PAS or the site SCADA. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
PM135PVoltage, current, power, power factor and frequency; COM1 RS-485 with Modbus RTU; optional COM2 moduleRead the 1-second phase and total values. The guide marks energy and power demand registers as PM135E and PM135EH only.
PM135EAdds class 0.5S import and export energy, time-of-use registers and data logs; the same ports and mapSame read path, plus the 32-bit energy counters from register 14720.
PM135EHAdds harmonic analysis to the 40th order, THD, TDD and K-factorSame read path; harmonic registers are marked EH in the guide.
COM2 modules ETH, RS232 and PROETH: 10/100BaseT with Modbus TCP on port 502. RS232: RS-232 or RS-422/485 with Modbus RTU. PRO: PROFIBUS DPETH gives the Modbus TCP route and RS232 a second Modbus RTU port. PROFIBUS is not a Modbus path; use COM1 instead.

Specifications

The PM135 is a multifunction three-phase power meter for panel mounting, with a backlit LCD, a load bar graph and an embedded controller with 16 setpoints. It measures true RMS voltage, current, power, power factor, neutral current, unbalance and frequency at 25, 50, 60 or 400 Hz. One expansion module can be fitted at the back: digital inputs and relays, analog outputs, or a second communication port.23

Models
PM135P power version; PM135E energy version, offered in certain regions only; PM135EH energy and harmonic version. All three have the same communication and control features.3
Inputs
Voltage up to 690 V AC line-to-line or 400 V line-to-neutral direct, or through PTs. Current through external CTs with 5 A or 1 A secondaries, or SATEC HACS sensors on the 40 mA option.23
Accuracy
Energy class 0.5S to IEC 62053-22 and ANSI C12.20 class 10 0.5%; voltage and current 0.2% of reading. The datasheet adds class 0.2 to IEC 61557-12.23
COM1
Built-in optically isolated RS-485 (3000 V AC), removable three-pin connector, up to 115.2 kbit/s. Factory settings: Modbus RTU, address 1, 9600 bit/s, 8 data bits, no parity, 5 ms response delay.12
Ethernet (ETH module)
Transformer-isolated 10/100BaseT on RJ45. Modbus TCP on port 502 and DNP3/TCP on port 20000, four connections in total (two Modbus TCP, two DNP3). Factory IP 192.168.0.203, mask 255.255.255.0, gateway 192.168.0.1.23
Response time
13 ms typical at 9600 bit/s, 11 ms at 19200 bit/s and 9 ms at 57600 or 115200 bit/s.1
Power supply
AC/DC option 85 to 265 V AC or 88 to 290 V DC, 9 VA; 9.5 to 18 V DC or 18.5 to 58 V DC options, 4 VA.23
Mounting
92 × 92 mm square or 4 inch round panel cut-out, or a 35 mm DIN rail with the DIN option; 114 × 114 × 109 mm; 0.70 kg.23
Environment
Operating -30 to +70 °C stand-alone, -30 to +60 °C with add-on modules; storage -40 to +85 °C; 0 to 95% humidity, non-condensing. Front panel IP54, body IP20.23

Interface

Documented measurements and integration boundaries for PM135.

  • Addresses are decimal and go on the wire as printed: register 13952 is sent as 36 80. A client that wants Modicon numbers adds 40001, or 400001 above 9999, so 13952 becomes 413953. FC03 and FC04 return the same registers.
  • 32-bit values are two registers, low-order word first, with the low word at an even address. They are long integers by default; register 246 can switch analog values, counters and energies to IEEE floats, which are also sent low register first. Read 246 before adding points.
  • Units depend on the device resolution at register 2390 (0 low, the default; 1 high). Low resolution: volts in 1 V, amps in 1 A, power in 1 kW, kvar or kVA. High resolution: 0.1 V and 0.001 kW with a PT ratio of 1 (1 V and 1 kW above it), and 0.01 A.
  • 1-second phase voltages V1, V2 and V3 at 13952, 13954 and 13956: UINT32 in volts. They are line-to-neutral in 4LN3, 3LN3 and 3BLN3 wiring and line-to-line otherwise. V12, V23 and V31 at 14012, 14014 and 14016.
  • Currents I1, I2 and I3 at 13958, 13960 and 13962: UINT32 in amps. Neutral current at 14466 and frequency at 14468 (UINT32, 0.01 Hz).
  • Per-phase kW at 13964, 13966 and 13968 and kvar at 13970, 13972 and 13974: INT32. kVA at 13976 to 13980: UINT32. Power factor L1 to L3 at 13982, 13984 and 13986: INT32, × 0.001. In 3-wire wiring the per-phase power and power factor read zero.
  • Totals: kW at 14336 and kvar at 14338 (INT32), kVA at 14340 (UINT32), power factor at 14342 (INT32, × 0.001), kW import at 14348 and kW export at 14350 (UINT32), average current at 14360.
  • Energy, PM135E and PM135EH only: kWh import at 14720, kWh export at 14722, kvarh import at 14728, kvarh export at 14730 and kVAh total at 14736. UINT32 in whole kWh, kvarh and kVAh, 0 to 999,999,999.
  • Per-phase kWh import L1 to L3 at 14848, 14850 and 14852, when phase energy calculation is enabled in the device options.
  • Registers 256 to 308 are a 16-bit basic set scaled 0 to 9999 between low and high engineering scales, with energies split modulo 10000. Prefer the 32-bit registers, which need no scale arithmetic.
  • Identity: serial number at 46080 (UINT32), model ID at 46082 (13510 PM135P, 13520 PM135E, 13530 to 13532 PM135EH), model name at 46084 to 46091 and firmware version at 46100.
  • Setup, password (2575), restart (2560), relay control (3244 to 3247), reset and clear registers (3404 to 3414) and the assignable map (0 to 239) accept writes. Keep them out of a monitoring poll.

Assessment

PM135P, PM135E and PM135EH, using the PM135 Modbus reference guide BG0515 Rev. A2 with installation manual BG0518 Rev. A4. Energy registers need a PM135E or PM135EH. Site check: read the device resolution at register 2390 and compare the first voltage read with the display. PROFIBUS, DNP3, IEC 60870-5 and SATEC ASCII are outside this guide. Read-only monitoring: no writes to setup, password, relay or reset registers.

InteroperabilityWell supported
SATEC documents Modbus RTU on COM1 and Modbus TCP on port 502, the supported function codes and exception responses, decimal addresses with the Modicon offsets, data types, low-word-first word order with worked examples, and unit tables for each resolution.12
AccuracySupported with conditions
Class 0.5S energy with 0.2% voltage and current, per-phase and total power, import and export energy and 1-second values. Energy needs a PM135E or PM135EH, and the units of every analog register depend on the resolution setting and PT ratio, so each point needs its scale confirmed once.123
SecuritySupported with conditions
A password option blocks setup changes and counter clears through communications, answering unauthorised writes with exception 01. It ships disabled with the password set to 0 and guards writes only, so enable it and keep the meter on a trusted network.12
ReliabilitySupported with conditions
The guide documents exception codes, a response time of 9 to 15 ms by baud rate, device status and communication counters, and a diagnostic LED on the front. Treat failed reads as missing data.12
RuggednessSupported with conditions
Rated -30 to +70 °C stand-alone and -30 to +60 °C with modules, IP54 front and IP20 body, IEC 61000-6-2 immunity at level 3, and 3000 V AC isolation on the RS-485 port. Panel or DIN-rail mounting inside an enclosure.23
ScalabilitySupported with conditions
Modbus addresses 1 to 247, up to 115.2 kbit/s, a wiring diagram for 32 meters on one bus, and 120 user-assignable registers that can gather scattered points into one read. The Ethernet module allows only two Modbus TCP connections at a time.12
LifecycleNot yet assessed
Firmware can be upgraded over Modbus RTU or Modbus TCP and the version is readable, and SATEC still publishes the 2013 reference guide and a February 2025 datasheet, but no support period is stated.123

Setup

Read V1 voltage from decimal register 13952

PM135 Modbus reference guide BG0515 Rev. A2, section 3.4, lists the 1-second V1/V12 voltage at registers 13952 and 13953 as UINT32 with unit U1, and section 2.7.2 sends 32-bit values low word first. Use that map as the starting point and compare the result with the display.

Request
01 03 36 80 00 02 CA 6B: Modbus address 1, FC03, register 13952 (0x3680), two registers, RTU CRC. Over Modbus TCP the same function, address and length go to port 502. To check the resolution first, 01 03 09 56 00 01 67 86 reads register 2390.
Address convention
The guide's register numbers are the zero-based PDU addresses in decimal: send 13952, which is 0x3680. A client that numbers holding registers from one shows it as 413953. Do not send 13953 or 413953 as the address.
Synthetic response
01 03 04 00 E6 00 00 1B C4: four data bytes, low word 00 E6 first, then high word 00 00.
Decode
UINT32 with the low word first: 0 × 65536 + 0x00E6 = 230. With the default low resolution U1 is 1 V, so V1 is 230 V. With high resolution and a PT ratio of 1 the same voltage arrives as 2300 (low word 08 FC) in 0.1 V. A client that takes the high word first reads 0x00E60000 = 15,073,280.
Acceptance
Keep the point when it agrees with V1 on the meter display at the same time. If it does not, check the resolution at 2390, the 32-bit register type at 246, the word order and the wiring mode before adding more points.

Acceptance: The response bytes are a synthetic decoder check, not a captured meter reply. A real reply must agree with the display before current, power and energy points are enabled.

  1. Identify the meter

    Read the model from the front label or the device information page: PM135P, PM135E or PM135EH. Note whether an ETH, RS232 or other module is fitted at the back, and record the PT ratio and CT primary current from the basic settings.

  2. Read the port settings

    COM1 is factory set to Modbus RTU, address 1, 9600 bit/s and 8 data bits with no parity. With the ETH module, the Network Setup menu shows the IP address. Enter the same values in the Edge client and leave the meter's settings as they are.

  3. Wire the connection

    For RS-485, connect the pair and the shield to the three-pin COM1 connector, give each meter its own address and terminate both ends of the bus. For Modbus TCP, connect the ETH module's RJ45 port to the site network.

  4. Make two reads

    Read register 2390, one register, to learn the device resolution. Then read V1 at 13952 for two registers and decode it low word first, as in the worked read below. Compare the result with the V1 voltage on the display.

  5. Add the points you need

    Add currents, powers and, on a PM135E or PM135EH, the energy counters from 14720. Check register 246 if any value looks like a float, and keep writes out of the polling configuration.

Common questions

Why does voltage read 2300 on one meter and 230 on another?
The device resolution setting changes the units. Low resolution, the default, sends volts in 1 V and amps in 1 A; high resolution sends 0.1 V and 0.01 A, and 0.001 kW for power when the PT ratio is 1. Read register 2390 (0 low, 1 high) and set the scale in Edge to match.12
Why does a 32-bit value read as millions?
The client is taking the high word first. The PM135 sends the low-order word in the first register and the high-order word in the second, for integers and floats alike. Swap the two registers in the Edge point definition.1
Can Edge read the PM135 over Ethernet?
Yes, when the ETH module, or a 12DIOR module with its Ethernet port, is fitted as COM2. The meter keeps a Modbus TCP server on port 502 permanently and allows two simultaneous Modbus TCP connections. The base meter has only the RS-485 COM1 port.23
Which PM135 has energy registers?
The PM135E and PM135EH. The reference guide marks the energy and power demand registers E, available in those two models, and the harmonic registers EH. Read the model ID at register 46082 to confirm: 13510 is a PM135P, 13520 a PM135E and 13530 to 13532 a PM135EH.13
Should I use the 16-bit registers at 256?
Only if the client cannot read 32-bit values. Registers 256 to 308 are scaled to 0 to 9999 between low and high limits that depend on the voltage scale, the CT primary current and the PT ratio, so each reading needs a conversion. The 32-bit registers carry the value directly.1
Can Modbus writes change the meter's settings?
Yes. Setup, reset, relay and password registers are writable. The meter ships with password protection disabled; when it is enabled, every write must be preceded by the password at register 2575, or the meter answers with exception code 01. A monitoring configuration should read with FC03 only.12

Sources

  1. Series PM135 Powermeters PM135P/PM135E/PM135EH Modbus communications protocol reference guide, BG0515 Rev. A2 (opens in a new tab) (PDF) SATEC
  2. PM135 Powermeter Series PM135P/PM135E/PM135EH installation and operation manual, BG0518 Rev. A4 (opens in a new tab) (PDF) SATEC
  3. PM135 datasheet, February 2025, with models and order string (opens in a new tab) (PDF) SATEC

Further reading

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