Janitza UMG 103-CBM

Power and energy meter

UMG 103-CBM adds a clock and local measurement storage to compact DIN-rail monitoring. Its firmware-scoped Modbus list offers both byte-order address spaces, so choose the documented bank before decoding a value.

Janitza UMG 103-CBM
  • Modbus RTU

Power and energy meter

Download Edge template

Compatibility

Compatible through Modbus RTU

The manufacturer documents local measurement reads that can be configured in an Edge Modbus client.

UMG 103-CBM, using the January 2023 address list for firmware 2.0 and higher. The earlier UMG 103 is a separate device with its own documentation and template. The downloadable starter reads 19 values from the big-endian bank, with complete two-register floats, multiplier 1 and exports disabled. Verify the installed CT/VT ratios first; fundamental power factor and reactive power are not total harmonic-inclusive values.

Connect it with

For the exact RS-485 model identified below

  • Modbus
  • Edge
  • Platforms
Power and energy meter
Interface
Gateway
Edge
Output
UMG 103-CBMUMG 103-CBM RS-485 port
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 local RS-485 Modbus RTU. The address list specifies 9600 to 115200 bit/s, eight data bits and no parity. It identifies two transmitted stop bits and external one-or-two-stop-bit support. Match the installed configuration before polling. The customer-platform output is optional; Edge remains the local system of record.

Specifications

The CBM model adds clock, battery and measurement-data storage to the UMG103 approach. That is useful when a communications interruption should not be confused with a loss of all local records. It does not mean a Modbus client automatically backfills that history: instantaneous polling and retrieval of the device’s recorded data are separate integration tasks.2

Documented item
5228001, UMG103-CBM3
Local data memory
4 MB with clock and measurement/energy recording3
Native interface
RS-485 Modbus RTU with A, B and GND connection3
Active energy class
0.5S with 5 A CTs on the published technical details; transformer and installation errors remain separate3
Address-list scope
January 2023, firmware 2.0 and higher1
Byte-order spaces
Printed address = big-endian; add 32768 for the little-endian copy1
Register update
200 ms in the address list; polling faster does not establish a fresher measurement1

Interface

This register map is for the UMG 103-CBM. UMG 103-CBM, firmware 2.0 and higher and UMG 103 without CBM have their own interfaces and are not covered here.

Communication settings

Interface
RS-485 Modbus RTU; use the installed address and baud rate
Serial framing
8 data bits, no parity, 2 stop bits on the UMG 103-CBM
Register bank
Documented big-endian addresses, FC04
Read with
FC04 (input registers)
Word order
High word first on every value
Addresses
Zero-based PDU addresses, as sent on the bus

From UMG103-CBM Modbus address list1.

Register map

Download
PointAddressHexFormatScaleUnit
Voltage L1-N 19000 0x4A38 FLOAT32 ×1 V
Voltage L2-N 19002 0x4A3A FLOAT32 ×1 V
Voltage L3-N 19004 0x4A3C FLOAT32 ×1 V
Voltage L1-L2 19006 0x4A3E FLOAT32 ×1 V
Voltage L2-L3 19008 0x4A40 FLOAT32 ×1 V
Voltage L3-L1 19010 0x4A42 FLOAT32 ×1 V
Current L1 19012 0x4A44 FLOAT32 ×1 A
Current L2 19014 0x4A46 FLOAT32 ×1 A
Current L3 19016 0x4A48 FLOAT32 ×1 A
Active Power L1 19020 0x4A4C FLOAT32 ×1 W
Active Power L2 19022 0x4A4E FLOAT32 ×1 W
Active Power L3 19024 0x4A50 FLOAT32 ×1 W
Total Active Power 19026 0x4A52 FLOAT32 ×1 W
Total Apparent Power 19034 0x4A5A FLOAT32 ×1 VA
Total Fundamental Reactive Power 19042 0x4A62 FLOAT32 ×1 VAr
Fundamental Power Factor L1 19044 0x4A64 FLOAT32 ×1 -
Fundamental Power Factor L2 19046 0x4A66 FLOAT32 ×1 -
Fundamental Power Factor L3 19048 0x4A68 FLOAT32 ×1 -
Frequency 19050 0x4A6A FLOAT32 ×1 Hz

Download the UMG 103-CBM register map as CSV

Assessment

UMG 103-CBM, using the January 2023 address list for firmware 2.0 and higher. The earlier UMG 103 is a separate device with its own documentation and template.

InteroperabilityWell supported
The address list defines functions, data types and both byte-order address spaces.1
AccuracySupported with conditions
Published accuracy and transformer-ratio annotations allow scoped measurement interpretation.3
SecurityNot yet assessed
The cited sources do not establish authenticated or encrypted Modbus telemetry.1
ReliabilitySupported with conditions
Clock and local measurement memory can retain records; retrieval is separate from instantaneous polling.2
RuggednessNot yet assessed
The cited material does not establish installation-specific environmental qualification for the proposed site.3
ScalabilitySupported with conditions
Multiple serial rates and explicit update timing support planned RS-485 polling.1
LifecycleNot yet assessed
The address list gives a firmware boundary, but no guaranteed support lifetime is established here.1

Edge template

This JSON file supplies the register map. Applying it to an existing meter replaces its sensor list while retaining the site connection, unit ID and enable state.

ModelConnectionPointsVersionUpdatedDownload
UMG 103-CBM Modbus 19 1.0.0 Download

Downloads need a signed-in account with Edge download access.

Use the template in Edge

  1. Import the JSON file

    In Edge, open Settings, then Devices and Templates. Choose Import JSON and select the downloaded file. Confirm that the model and template name match your device.

  2. Load the map for your meter

    For a new Modbus device, use Load Template before entering the manufacturer or model; it fills those fields and the register list. Set the name, site connection and unit ID, check the polling enable state, then test before saving. For an existing device, apply only to the matching model; this replaces its sensor list but retains its connection, unit ID and enable state.

  3. Test a reading

    Use Test in the wizard and compare a known reading with the meter display. Check its unit, sign and scale, then confirm that timestamps keep advancing. These starter maps are read-only and leave exports off until you configure them.

Setup

Read the big-endian voltage entry

The firmware 2.0 address list places L1-N voltage at decimal 19000 as Float in V and supports FC04.

Request PDU
04 4A 38 00 02
Address calculation
19000 decimal = 0x4A38; read two 16-bit registers
Synthetic data example
43 66 00 00 is IEEE-754 float32 big-endian 230.0 V
Alternate byte-order bank
19000 + 32768 = 51768 (0xCA38), the little-endian copy

Acceptance: Keep the requested bank and decoder together. These example data bytes are synthetic, not a captured reply. Validate the actual measurement and the configured measuring ratios before using power or energy totals.

  1. Confirm CBM identity and firmware

    Record the complete UMG103-CBM identity and firmware. Use this address list only within its firmware 2.0-and-higher scope. Do not import the earlier UMG103 template solely because the names are similar.

  2. Set the serial path

    Record the meter address and serial settings. The address list supports 9600, 19200, 38400, 57600 and 115200 bit/s with eight data bits and no parity. Configure the client to match the installed meter.

  3. Use one byte-order address space

    For the printed big-endian L1-N voltage entry, use decimal 19000 (0x4A38), FC04 and two registers. Do not subtract one. The little-endian copy is 51768 (19000 + 32768), not a different voltage measurement.

  4. Check scaling at the chosen entry

    Compare the complete float voltage with a known reference. For other entries, retain the listed type, unit and scaling factor. The list says CT/VT-marked values exclude the corresponding transformer ratio; do not assume every alternate table reports primary units.

  5. Separate fresh reads from recorded history

    Collect current measurements with timestamps and stale-state handling. A 200 ms register update is not a guarantee that every network poll contains a new sample. Treat historical-memory retrieval as a separate documented operation rather than filling a communications gap with zeroes.

Common questions

Is UMG103-CBM the same profile as UMG103?
No. The CBM model has its own firmware-scoped address list and recording features. This guide does not silently extend the older UMG103 template to it.1
Why are two addresses available for the same voltage?
Janitza provides big-endian data at the printed address and little-endian data at that address plus 32768. This is a deliberate alternate representation. Choose the bank and decoder together, rather than changing both until a number looks plausible.1
What do CT and VT beside an entry mean?
The address-list legend says the corresponding current or voltage transformer ratio is not included in that value. Apply the documented scaling and ratio for that exact entry; do not transfer assumptions from the frequently used Float table to every other table.1
Will routine polling retrieve the stored data automatically?
No. The device has local measurement storage, but reading instantaneous values does not by itself request historical records. Preserve missing intervals honestly until a documented historical-data integration is implemented.2

Sources

  1. UMG103-CBM Modbus address list (opens in a new tab) (PDF) Janitza
  2. UMG 103-CBM product overview (opens in a new tab) Janitza
  3. UMG 103-CBM technical details, item 5228001 (opens in a new tab) Janitza

Further reading

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