CLMod – RS485 to current loop converter


CLMod is an RS485 to 20 mA current loop converter. CLMod can remotely gather data from electricity meters. This converter was developed to read multiple meters of data over a 20mA current loop interface with long-distance lines up to 2km. CLMod with 6 current loop interfaces is capable of reading data up to 30 meters (5 meters per single current loop). CLMod is protocol agnostic you can use any type of serial protocol.


  • 6 independent 20mA current loop interfaces
  • Galvanic 3kV(rms) isolation
  • LED indication of data transmission on every current loop interface
  • Supports 5 meters per current loop (30 meters total)
  • Baud rates: 1200 to 9600
  • Automatic open-loop detection and disconnection
  • Fail indication for each current loop
  • Integrated current loop protection
  • Compatible with Elgama Elektronika meters
  • RS485 interface for RTU/Datalogger
  • Operating temperature: -40°C +80°C
  • Dimension 101x119x17.5mm


  • Communication standard: RS485
  • Communication protocol: Modbus (RTU), DLMS/Cosem and IEC 62056-21
  • Speed: 1200 – 9600 baud

Electrical characteristics

  • Termination resistor: Software selectable, 120Ω
  • Power supply: 24VDC / 21.6-26.4VDC (full range)
  • 3kV galvanic isolation with isolated DC/DC power supply inside(RS485 and power supply is isolated from current loop interfaces)
  • Integrated current loop protections:
    • Rated current: 0,2A
    • Max pulse discharge current (8/20 µs): 10kA
    • Reaction time in µs: 1


Device data
Article numberCLMOD
Product descriptionRS485 to current loop converter. With 6 independent current loop 20mA interfaces.
Configuration softwareNot required
Warranty2 years
Interfaces and functions
Meter interfaces6 independent current loop interfaces (20mA)
interface capacity5 meters per interface (where voltage drop per meter <2VDC)
Total metersup to 30 (6×5 meters)
Interface protection>3 kV individual isolation of each interface
Max pulse discharge currentup to 10kA (8/20 µs)
Reaction time>=1µs
Cut off current > 200mA
Max input voltage33 VDC
Interface and communication
RS485 interfaceANSI/TIA/EIA-485-A-1998
Communication protocolsProtocol agnostic (transparent) tested with:
– Modbus RTU;
– IEC 62056-21;
– IEC 62056-31.
Baudrate1200 – 9600 baud
ParityNone, Even, Odd
Terminating resistors120 Ohm (configurable)
Current loop interface6 independent interfaces
Galvanic isolation3 kV
Max distance<2 km per interface
Max metersup to 5 meters per interface
Protection on every current loop interface independent
Power supply
Auxiliary power supply9-33VDC (full range)
Power consumption40mA @ 12VDC, 20mA @ 24 VDC
Insulation voltage3 kV
Operating conditions
Operating temperature-40°C … 55°C
Storage temperature-40°C … 85°C
Relative humiditymax. 95 % (non condensing)
Protection classIP20
Dimensions and installation instructions
Case height x width x depth119 x 17.5 x 101 mm
Installation typeDIN Rail mounting



CLMOD6 – 6x current loop interfaces for a meter with RS485 interface for a communication device.

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