Janitza UMG 509-PRO

Power and energy meter

UMG 509-PRO is a panel analyser with electrical and residual-current measurement functions. Janitza’s user manual prints an FC03 query for L1-N voltage at literal decimal address 19000. The guide uses that narrow, read-only path while keeping residual-current sensing, event analysis and other communications outside the basic voltage check.

Janitza UMG 509-PRO
  • Modbus RTU

Power and energy meter

Compatibility

Documented read-only Modbus path

Janitza supplies an explicit FC03 voltage request for the UMG 509-PRO RS-485 Modbus server.

UMG 509-PRO using the June 2024 address list and November 2024 user manual as a best-effort starting point. Poll the instrument’s RS-485 Modbus server at the literal addresses below. Record its firmware and configured CT/VT ratios. The older UMG 509 and UMG 512-PRO have separate documents.

Connect it with

For the documented RS-485 Modbus RTU server interface

  • Modbus
  • Edge
  • Platforms
Power and energy meter
Interface
Gateway
Edge
Output
UMG 509-PROMeter RS-485 terminals
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
Use the local RS-485 server interface and match the installed device address and framing. Do not confuse Ethernet web access or a master bus role with this read path. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
UMG 509-PRORS-485 Modbus server; separate Ethernet and analysis functionsThis guide reads live measurements from the RS-485 server.
UMG 509 and UMG 512-PRODifferent model revisions and manualsDo not transfer the UMG 509-PRO map or commissioning steps.

Interface

Documented measurements and integration boundaries for UMG 509-PRO.

  • L1-N voltage as Float32 in V at literal address 19000.
  • Current, three-phase active power and Wh energy in the frequent-readings bank.
  • Residual-current measurements with their own sensors and configuration.
  • Power-quality and event analysis beyond a single present-value read.

Assessment

UMG 509-PRO using the June 2024 address list and November 2024 user manual as a best-effort starting point. Poll the instrument’s RS-485 Modbus server at the literal addresses below. Record its firmware and configured CT/VT ratios. The older UMG 509 and UMG 512-PRO have separate documents.

InteroperabilityWell supported
Janitza prints an FC03 request for L1-N voltage and the map defines the matching Float address and byte-order banks.12
AccuracySupported with conditions
CT-based power analysis and residual-current monitoring need the correctly installed sensing circuits and transformer ratios.23
SecurityNot yet assessed
Authenticated or encrypted serial transport for this read path is not established by the retained manuals.2
ReliabilitySupported with conditions
The front display and example telegram offer independent commissioning checks; stale or invalid samples still need handling.2
RuggednessSupported with conditions
The manual specifies panel installation and environmental conditions that must match the cabinet.2
ScalabilitySupported with conditions
The addressed RS-485 server permits a designed bus, subject to installed roles and polling load.12
LifecycleNot yet assessed
The retained documents identify the model and map but do not establish a future support period.12

Setup

Use Janitza’s documented voltage request

The user manual gives a query to read L1-N voltage at literal decimal address 19000 in Float format.

Request PDU
03 4A 38 00 02: FC03, address 0x4A38, quantity two registers. Add configured RTU unit address and CRC.
Address proof
The printed request uses 4A 38, so do not subtract one from 19000.
Decode
The selected big-endian bank is IEEE-754 Float32 in V. Synthetic bytes 43 66 00 00 decode to 230.0 V.
Acceptance
Compare the current read with the simultaneous device display on a valid L1-N circuit.

Acceptance: The manual proves the request address and type; the synthetic payload is only a decoder vector. Actual response and wiring still need on-site acceptance.

  1. Identify the instrument

    Record the UMG 509-PRO model, firmware, CT/VT ratios and residual-current sensor arrangement before configuring data collection.

  2. Match the serial settings

    Confirm the RS-485 server role, unique device address, baud rate and framing. The address-list transfer section gives 8 data bits, no parity and two stop bits for the UMG.

  3. Read L1-N voltage

    Send FC03 to 0x4A38 (decimal 19000), quantity 2, for L1-N voltage. Janitza’s manual prints this exact starting-address pair.

  4. Check the decoder and scaling

    Decode the complete big-endian Float32 in V, and compare the fresh value with the front display. The selected Float already incorporates configured transformer factors.

  5. Add current, power and frequency

    Add L1 current at 19012 (0x4A44) in A, total active power at 19026 (0x4A52) in W and frequency at 19050 (0x4A6A) in Hz. Read each complete value with FC04, quantity 2, big-endian IEEE-754 Float32, multiplier 1. For example, the current request PDU is 04 4A 44 00 02. These Float readings include the configured transformer factors; do not apply CT/VT ratios again. Compare current and signed power with the display under a known load. Keep the printed bank and decoder together; use the separate +32768 bank only with its little-endian decoder.

Common questions

Is 19000 one-based or a literal PDU address?
It is the literal address in this map. Janitza’s example sends high byte 4A and low byte 38, which is hexadecimal 0x4A38, decimal 19000.12
Can I use the UMG 512-PRO map?
No. UMG 509-PRO has its own retained address list and manual. Match the actual model and revision.12
Do the Float readings need a second CT multiplier?
No. The address-list introduction says Float and integer values include configured transformer factors. Check those settings in the instrument.1

Sources

  1. UMG 509-PRO Modbus address list, document 1.059.004.2.n (opens in a new tab) (PDF) Janitza
  2. UMG 509-PRO user manual with FC03 voltage telegram example (opens in a new tab) (PDF) Janitza
  3. UMG 509-PRO product description (opens in a new tab) Janitza

Further reading

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