A pacometer,[1]​ coating meter[2]​ or pacometer[3]​ (in civil engineering jargon),[4]​ is a device used to determine the thickness of glass, paper, or a reinforced concrete structure.[5]​ In this last context, as a coating meter it allows locating the reinforcing bars of a structure and specifying the thickness of the concrete coating using the measurement of the disturbance of a magnetic field generated on the surface of the same.[6]​.

The impulse induction method is based on the induction technology of an electromagnetic impulse to detect rebar. The probe coils are periodically charged with current pulses and therefore generate a magnetic field. Eddy currents are produced on the surface of any electrically conductive material that is in the magnetic field, inducing a magnetic field in the opposite direction. The resulting induced voltage change can be used to determine the position and size of the armature bars; those that are closer to the probe or larger produce a stronger magnetic field.[7]​.

Modern rebar detectors use different coil assemblies to generate various types of magnetic fields. Advanced signal processing allows not only localization of reinforcing bars, but also determination of coating thickness and estimation of bar diameter. This method is not affected by non-conductive materials such as concrete, wood, plastics, bricks, etc. . . However, any type of conductive material within the magnetic field will have an influence on the measurement.[7]​.

Metal detectors are less sophisticated devices that can only locate metal objects below the surface. The impulse induction method is one of the most used solutions.

Advantages:[8]​.

Disadvantages:

Early diagnosis and analysis of the condition of concrete cover and apparently healthy reinforcement allows preventive corrosion control measures to reduce unwanted risks to structural safety.[9]​ Bundesanstalt für Materialforschung und-prüfung (Federal Institute for Materials Research and Testing, Germany) has developed a robotic system equipped with sensors to accelerate the collection of various criteria used for diagnosis. In addition to ultrasound, ground penetrating radar, concrete resistance, potential field, the eddy current method implemented in the Profometer 5 was used to measure the concrete cover.[10]​.