Transformer Rectifier


The MERLIN Transformer Rectifier Monitor is a small, compact unit housed within the rectifier cabinet. It checks the rectifier performance and communicates (via either an internal or external antenna) using the GSM network. All data is automatically transmitted in a management report to the system HQ where it is accessed online using Abriox’s MERLIN iCPSM software, or at a PC using CPSM software.

MERLIN TR Monitors will carry out the functional checks of rectifier output (voltage and current) required in order to comply with regulatory guidelines. They will quickly repay their capital cost when compared to monthly manual checks.

MERLINs will report immediately if an output alarm threshold is exceeded, they will also check that the rectifier remains powered by its external electrical supply. If the power fails, an alarm is transmitted and the MERLIN’s internal batteries take over monitoring for up to 2 years.

A key feature of the Abriox MERLIN system is control by text messaging. Once installed, monitors are easily and quickly set up using a mobile phone. Further configuration (e.g. alarm levels) can be programmed and on-demand readings can be taken of all monitored parameters. In addition, synchronised interruption cycles can be started and stopped directly from a mobile phone.

Abriox’s iCPSM web software provides access from any internet-enabled PC to a password-protected CP database that is unique to each customer. Users can configure and control MERLIN monitors, view rectifier CP data in graphical and numerical formats or export data for further analysis and archiving. A stand-alone PC-based version is also available.



  • Compact size - quick and easy to install, typically 30 minutes on site
  • Hourly check of rectifier outputs, ON/OFF potentials
  • Immediate alarm generation (user preset thresholds on all channels)
  • Weekly report with min, max and average of all parameters for the week
  • Pipeline locate feature (offered on MERLIN Excel)
  • Mobile phone test & set-up, ondemand readings and control of rectifier output relay
  • Synchronisation (option) enables close interval surveys to be carried out more quickly, with no rectifier set-up required
  • AC powered (110V to 230V) with 2-year battery backup. DC power option for solar stations
  • Sealed weatherproof unit with robust lightning protection and wide operational temperature for all extremes
  • Web-based or PC-based user interfaces with graphical/tabular displays and data export



  • Economically monitors rectifier performance
  • Alarms when protection inadequate or power fails at rectifier
  • Data sent in automatically, wirelessly
  • Labour freed for data interpretation and follow-up
  • Health and Safety risks reduced
  • Zero carbon footprint for CP monitoring - no vehicle surveys required


Technical Specification


  • Rectifier AC supply (indirectly)​
  • Rectifier output voltage 0 to 150V DC 0.1V resolution
  • Rectifier output current (using shunt) ± 100mV DC 0.01mV resolution
  • ON potential of the pipe​
    • ± 4V DC with AC rejection
    • 1mV resolution
    • 10 MOhm input impedance
  • OFF potential of the pipe (using optional relay)​


  • Fail-safe relay drive, 0.43A maximum at 12V DC nominal
  • Interruption drive, 0.43A maximum at 12V DC nominal
  • Output patterns from 1s to 60s with 0.1s resolution
  • Short circuit and surge protection
  • Synchronisation error less than 1ms

Physical Dimensions (H x W x D)
      - 125mm x 85mm x 55mm
      - 450g
IP Rating
      - IP65
Operating Temperature
      -40°C to +85°C 100% condensing humidity
Lightning Protection
      - Surge protection on all external inputs and outputs 2,500A at 3,000V (8/20us)
      Additional protection using recommended arrestors
Backup Battery
      - 2-year life, replaceable battery module
      - GSM/SMS
Software Management
      - iCPSM (web-based) or CPSM (PC-based)

Enhanced models offer additional CP measurements (ON and OFF potentials) as well as the facility to synchronise remotely with other rectifiers on a pipeline for CIPS (Close Interval Potential Surveys) or DCVG (Direct Current Voltage Gradient) surveys.

Select from 4 models:

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