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Miro-F Class A Transformer Monitor and Logger

The Miro-F Class A power quality recorder is a precision instrument designed specifically for transformer monitoring. It offers comprehensive and reliable LV side transformer monitoring and includes measurements of three phase voltages, four currents (three phases and neutral) and two temperatures. It is equipped with integrated remote cellular communications (3G/4G) and is therefore ideal for network asset management.

Large scale network monitoring solutions utilising multiple Miro-F instruments can be implemented (as shown in figure 2); providing network engineers with information for planning, operations, maintenance and network modelling.

 Proudly designed and manufactured in Australia by CHK Power Quality Pty Ltd.


The Miro-F (Figure 1) incorporates fixed voltage leads and removable current sensors. The current sensors (Iron core clamp on CTs or Rogowski coils) can be customised to match the transformer load. The Miro-F incorporates a back-plate and four magnetic feet for quick and easy installation on to the transformer. The weatherproof design (IP66) enables installation on pole-top transformers.

Automatic DNP3: Data points polled periodically by a DNP master, stored in third party database, viewed by third party viewer for interrogation and analysis.

Automatic FTP uploads: Full PQ data including event captures pushed periodically to FTP server, to be viewed by proprietary Citrus software or converted to PQDIF format for use with third party analysis tools.

CiDR (Citrus Data Retrieval): CiDR is a service for automatically collecting data from the Miro loggers. It allows users to schedule downloads of Miro files; Upgrade firmware; Synchronise the time; and Automatically convert Miro data files into PQDIF format.

Manual TCP/IP: Connect using CITRUS TCP/IP connection, inserting a static IP address which provides a transparent connection and allows configuration, download of logged data and firmware updates.

The above systems can be deployed anywhere within cellular coverage and can support multiple Miro-F instruments. Secure communication can be established using SSH (Secure Shell) for TCP/IP and FTPES (File Transfer Protocol Explicit Security) for FTP.

Key hardware features

  • Certified to IEC61000-4-30, Class A
  • Weatherproof enclosure – IP66
  • AC voltage and current measurements.
  • Surface and ambient temperature probes.
  • Expansion port (optional) allows for system expansion to include additional sensors, input/output controls and custom interfaces which broaden the Miro-F system platform. Example interfaces include DGA, Hydrogen and Bushing monitors.
  • Powered from Phase A to Neutral.
  • Starts logging on power up.
  • Adjustable log interval.
  • Gapless logging: User can download data, clear log memory and configure the device with no interruption to logging.
  • Internal backup battery: 5-minute back up time as standard, with option to extend upon request.
  • Optional GPS and external antenna.
  • Cellular communications options (3G/4G) are integrated within the enclosure – no additional peripherals required other than an external antenna.
  • Integrated WiFi for Android and iOS mobile applications.
  • Graphical colour display
    • Voltage and current waveforms
    • Phasor diagrams.
    • Measurements
    • Status information.
    • User defined screen.
  • Logged memory: 8GB

Key software (CITRUS) features

  • The CITRUS platform is powerful, easy to use and intuitive application software that supports all CHKPQ products. It provides tools for: device management; data analysis; and reporting.
  • Configurations
  • Pre-defined configurations for easy setup.
  • Create and store different configuration files for quick retrieval.
  • Online monitor to view ‘live’ measurements.
  • View multiple log file data on the same graph to compare PQ measurements with GPS synced time stamps.
  • Event type filter to view only desired events.
  • Analysis and Compliance reporting
  • Energy; Daily Min/Max; ITI (CBEMA) curve.
  • 24-hour scatter plot (Figure 4).
  • Voltage and Current histogram (Figure 5).
  • Customised reports (available upon request).
  • Views
  • Ability to edit an active view: Text and arrow annotation and title options available.
  • Generate a PDF, CSV file, or table.
  • Save and Print view.
  • Split or combine voltage and current graphs.
  • Multiple measurements on a single graph.
  • Horizontal and vertical cursors for accurate measurements.
  • Horizontal and vertical axes zooming functions.
  • PQDIF export – ‘PQView’ compatible.
  • Automatic FTP uploads.

Download the datasheets and manuals for Miro-F Transformer monitor and logger through our download centre

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