MERLIN Cathodic Protection Monitoring

//MERLIN Cathodic Protection Monitoring
MERLIN Cathodic Protection Monitoring 2017-06-07T13:05:42+00:00

Cathodic Protection (CP) is an important method of preventing corrosion on buried metal pipelines. But it must be applied at the correct level. Every pipeline operator must carry out regular measurements of CP – at rectifiers or solar stations and at CP tests points (in impressed current systems) and at sacrificial anodes (in galvanic systems).

Some key pipelines – crossing main roads, rivers or centres of population – may have additional protection against corrosion in the form of a sleeve filled with an inert gas (Nitrogen). The gas pressure in the sleeve has to be maintained above a specific threshold, which requires regular checks.

Collecting and analysing field measurements is labour-intensive and costly. And (very importantly) they can only be reactive – problems can lie undetected for long periods, during which the pipeline is insufficiently protected.

Introducing MERLIN

Abriox has developed the MERLIN system with input from pipeline operating companies and independent CP consultants.  The MERLIN system remotely monitors cathodic protection levels at rectifiers and test points along pipelines, and also the pressure within nitrogen sleeves.

All measured data is automatically transmitted in a management report to the system HQ where it is displayed and archived in Abriox’s CPSM software or online via iCPSM.  The system is proactive - identifying potential corrosion problems wherever and whenever they occur and alerting the operator immediately.

MERLIN Remote Cathodic Protection Monitors (also known as Remote Monitoring Units - RMUs) are commonly used at:

  • Rectifiers and Solar Stations - measuring electrical supply, voltage output, current output, ON and OFF potentials and also interrupting the current output for above ground surveys
  • Test Stations, CP Posts and Riser Posts – measuring pipe to soil ON potentials, instant OFF potentials, coupon currents
  • On-shore Tanks, Sacrificial Anodes, Isolation Joints and Critical Bonds
  • Pipeline Sleeves - measuring nitrogen/inert gas levels


MERLIN has major economic, operational, safety and environmental benefits:

  • Reducing the cost of data collection and pipeline surveys
  • Improving the quality of data
  • Reducing health and safety risks to technicians
  • Increasing the efficiency of Integrity teams
  • Zero carbon footprint for data collection
  • 24/7 monitoring

MERLIN is installed on every continent, providing significant cost savings and making our customers’ operations more efficient.


A completely wireless remote monitoring system for the oil, gas, petrochemical pipeline protection industries.
We believe it is the most cost-effective remote cathodic protection monitoring solution available today!

Innovative Design

Through careful consideration of what pipeline operators require from a monitoring system, Abriox has been able to combine low power consumption electronics with remote telemetry to create a compact, affordable package offering all the key CP measurements.

Our design is intelligent, yet practical. Some of the points our customers repeatedly comment on are:

  • The ease of installation of our monitors. Within a few minutes of being on site it is possible to install, commission (in the software) and take the first measurements from a MERLIN monitor. No specialist equipment is required, simply standard tools and a cellphone.
  • The ability to get readings in the field from our monitors. Transformer Rectifier monitors are continuously powered, so technicians can get readings sent directly to their cellphone on demand. This saves a lot of time in checking data and ensures that maintenance visits are only made when really required.
  • Reliability is ensured by extensive testing during production – all units are 100% tested – with particular attention to ingress and lightning protection. Careful electronic design has also made MERLIN extremely stable so that it does not drift and requires only an occasional functional check against a calibrated multimeter.

3G/2G & Satellite Communications

MERLIN DX monitors use SMS (text) messaging (over the 3G/2G network) to report data from the field to a central HQ. This method has several advantages:

  • Massive investment in infrastructure by network providers
  • 90% coverage in most countries
  • Excellent coverage in virtually all urban and semi-urban locations
  • Expanding coverage worldwide into remote/rural areas
  • Proven reliability
  • Low cost


SMS communication enables MERLIN monitors to be set up in the field using a cell/mobile phone.

MERLIN monitors incorporate an internal antenna which, in most locations, will be quite adequate. In weak signal areas, units can be equipped with an external antenna (model dependant).

The MERLIN system is independent of network provider and Abriox will work with users to secure the most advantageous communication package in their country. We can usually supply our monitors with a airtime package – but we can also factory fit free-issued SIMs or supply monitors for users to fit their own SIMs.

For areas of the world where there is no 3G/2G network coverage, the MERLIN XT Transformer Rectifier Monitor offers 100% global satellite communication. Abriox selected the Iridium system for its high performance and high integrity. Among its many advantages over other satellite systems are:

  • Global coverage
  • Compact antenna
  • No satellite antenna alignment concerns
  • Low power consumption
  • Large data packets
  • Low, uniform, message latency


The last point there is very important - some satellite systems can take up to an hour to send/receive a message if the system is busy, Iridium is 20 sec to 2 minutes (maximum). This is because the Iridium meshed constellation relays data from satellite to satellite without touching ground until it is downlinked at an Iridium gateway. This means the MERLIN XT can be very quickly installed with negligible waiting time – a huge advantage to our customers.

Built-in Lightning Protection

Pipelines are a significant attractor for lightning, and in some regions of the world strikes can occur frequently. Abriox has always designed lightning protection into our MERLIN monitors.

To improve the MERLIN protection further, Abriox worked with Cobham Technical Services, one of the world’s leading specialists in lightning testing and consultancy.

As a result of the work with Cobham, MERLIN’s protection against high energy surges has been substantially enhanced through electronic design (surge protection circuitry, more resilient components and a revised physical layout) and the identification of new surge arrestors with improved performance.

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Innovative Software

Data from MERLIN Monitors is automatically stored and transmitted in a management report to the system HQ where it is displayed and archived in the MERLIN CPSM software (Desktop application) or accessed on-line via the internet based iCPSM.

Monitors can be configured to send their data to two HQs; changes made at one HQ are automatically updated at the other HQ with a full audit trail of all changes made to the system.

  • CPSM (Cathodic Protection System Manager) - PC based database software package for displaying, archiving and exporting data from MERLIN monitors.
  • iCPSM (Internet-based Cathodic Protection System Manager) - Online database software package for displaying, archiving and exporting data from MERLIN monitors.

User access levels (Controller, Technician, Viewer) are allocated via the system licence to ensure that the appropriate features are available to authorised personnel.

View the MERLIN Range

We believe MERLIN to be the most comprehensive CP monitoring system available, providing unrivalled performance and reliability and making it the system of choice for CP professionals.

Rectifier and Solar Station Monitors

Test Post and Bond Monitors

Nitrogen Sleeve Monitors

Database Software


Download the datasheets for the complete range of MERLIN Monitors and our other products from our support section