PIG Detector

The ClampOn DSP PIG Detector registers and monitors when the PIG is passing the point of installation. Providing reliable information about the passage of the PIG increases pipeline integrity and produces cost savings.

How it works

ClampOn PIG detection systems perform this operation in a simple and safe way as they only monitor the PIG from the outside of the pipe. The sensor is simply clamped onto the pipe, eliminating any need for welding or drilling during installation. There is no need for inserts in the PIG and the system is capable of detecting all types of PIGs or plugs.

Principle of operation

The ClampOn DSP PIG Detector, based on our Ultrasonic Intelligent Sensor Technology, represents the latest state-of-the-art technology. This acoustic instrument accurately detects the passage of all types of PIGs in real time, giving instant warning to the operator. Its signal output can also be used to indicate the amount of debris pushed ahead by the PIG during pipeline cleaning operations. ClampOn PIG detection systems have been successfully tested and used by a large number of clients for many years, and this latest model makes the system even more compact and reliable. DSP (Digital Signal Processing) represents leading-edge technology in this field and keeps us ahead of the competition.



The ClampOn DSP PIG Detector, available in topside and subsea versions, is a more compact and user-friendly unit than other instruments on the market. It is easier to install in the field and easier to move to other locations.

DSP involves complete digitalization of the system and the elimination of analogue filters. This technology is increasingly used in a wide range of “smart electronic devices” as it provides sufficient capacity to perform advanced signal-processing tasks in real time. Such devices include medical diagnostic instruments, radar and sonar systems and mobile phones. ClampOn is the only manufacturer of PIG detection systems to use DSP, which enables the sensor to operate in several frequency ranges simultaneously, eliminating the danger of the detector being triggered by noise sources other than PIGs.


Our PIG detector can be interfaced with the control system using either:

  • Digital RS485 interface
  • Analogue 4-20mA interface
  • Digital output, VFC (Volt Free Contact)

Detecting the PIG passing is done by detection criteria’s in the detector itself or using our computer software. There are also two sets of detection methods available, fixed threshold and percentage of signal. The latter is often used with unstable flow conditions.

It is recommended to use the digital interface (RS485) and a computer running our software for following reasons:

  • Detection criteria’s can easily be set in the software by an operator.
  • All data will be logged and all PIG passing will be recorded and time stamped.
  • Trends will be available for correct calibration of detection.
  • Method of detection can quickly be changed if needed.


PIG Detector

Method of operation

Ultrasonic (acoustic) Optional dual detection with magnetic flux gate


Intelligent DSP inside the instrument

Method of installation

Non-intrusive, clamped to pipe surface

Detection mode

Default: Acoustic, Optional: Magnetic

Ambient temperature

Ex i: -40 °C ≤ T amb ≤ +60 °C
Ex d: -50 °C ≤ T amb ≤ to +80 °C

Pipe temperature

-40 °C to 125 °C [-40 °F to 257 °F]

Power consumption

Ex i: 1.9W 3.3W (alarm, light illuminated), Ex d: 1.2W 1.5W (alarm, light illuminated)


Relay, 4-20 mA, RS-485 (Modbus RTU, ClampOn DSP protocol)

Alarm indication

Local indicator, remote indicator (via instrument relay) digitally via computer/controller with ClampOn software or in DCS/MCS, or 4-20 mA

Sensor material

Stainless Steel 316L

Mounting bracket material

Stainless Steel 316L, carbon steel or duplex

Weight (sensor only)

Ex i: 2.1 kg (4.6 lb)
Ex d e: 3.2 kg (7.1 lb)

Dimensions (ø x h)

Ex i: 80 mm x 135 mm [3.2 in x 6 in]
Ex d: 114 mm x 185 mm [4.5 in x 6.6 in]

Ingress protection

Ex ia: IP 66&68 Ex d e: IP 66&68