micma electronic GmbH
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Precise measurement of the power supply mainsfrequency


The measurement device micromax-f determines the frequency of the supply voltage by the time between the zero crossings of the sine wave of the supply voltage. The timebase is calibrated at regular intervals with a temperature compensated crystal, whereby a high accuracy is achieved. The model -fgps can calibrate the timebase via the signal of the GPS satellites (Global Positioning System).

The measured values are averaged over a second and are then available for further processing or output. For this purpose the system has a web client to actively send the measurement data to a server (UDP and Modbus/TCP), and a web server to enable a query for the data and the device settings. The model -f485 has a built in Modbus/RTU server, which provides the data to a Modbus client.

A data export via different interfaces (e.g. via RS232, RS485, SPI, CAN, LIN) and a data logger function are optional available.
The model -fgps requires GPS reception in order to obtain the current time and to carry out time-synchronized measurement. It has an external, weatherproof Garmin GPS receiver, connected with a 5 m cable for flexible mounting.

Technical data

Measurement device

  • Case size: 120 * 105 * 45 mm
  • (-fh with DIN rail mounting): 120 * 105 * 57 mm
  • Weight: ca. 350 g
  • Operating temperature: -25 C bis +85 C
  • Storage temperature: -40 C bis +85 C

GPS-receiver (only -fgps)

  • Case size: 61 * 61 * 19,5 mm
  • Weight: 160 g
  • Cable Length: 5 m
  • Operating temperature: -30 C bis +80 C
  • Storage temperature: -40 C bis +90 C
  • Case IP Code: IPX7 (waterproof IEC 60529)

Railmount power supply (only -fh)

  • Case size: 54 * 90 * 63 mm
  • Power supply: 6 V AC
  • Operating current: < 450 mA
  • Operating power: < 4,5 VA
  • Netzteil: 230 V AC

Measurement Specifications

  • Range: 45 Hz - 65 Hz
  • Resolution: 0,1 mHz
  • Accuracy (1 second period): +/- 1 mHz
  • Accuracy (<250 ms period): +/- 5 mHz

Available models

  • Basic, GPS or RS485
  • Standard case or DIN rail mounting