News - General T&M

True-RMS clamp meter measures down to 1mA

13 September 2010 - GMC-I PROSyS has introduced the CP41 AC/DC True RMS Clamp Meter, a hand-held unit that combines simplicity of operation and convenience with non-invasive measurement of current to an accuracy of ± 1% of reading and resolution of 1mA.

The CP41 meets the needs of a wide range of users in industrial and automotive markets. Its range and sensitivity allow measurement of operating currents, and leakage currents, with a single product, and without breaking connections in the circuits under test. Measurement capability in the mA range permits verification of 4-20mA current-loops in process-control systems, while the meter is equally applicable to testing light-industrial and residential electrical installations.

The CP41 measures, selectably, DC or AC currents with a resolution of 1mA and, on its AC ranges, with true-RMS current indication. It maintains accuracy even in electrically noisy environments, featuring excellent rejection of external magnetic fields together with a very high level of immunity to interference from voltage transients. The meter is battery-powered, and has a 4-digit liquid-crystal display: full-scale readings are up to 4A or 40A, with auto-ranging and auto-zero functions. GMC-I PROSyS also offers a second variant of the CP41, the CP410, which measures higher currents: its auto-range full-scale limits are up to 40A or 400A.

The GMC-I PROSyS CP41 uses compensated Hall-Effect sensing in a patented magnetic circuit, to detect the magnetic current generated by the current of interest; this technology allows measurement of both DC and AC currents. AC currents are measured over a frequency range of 15 to 400 Hz.

In operation, the user opens the jaws of the probe, which have a 25-mm aperture, and closes them around the conductor carrying the current of interest: advanced design of the magnetic circuit means that location of the conductor within the aperture is non-critical and errors due to off-centre positioning are negligible. The CP41’s design supports safe, single-handed operation in hazardous areas, assisted by a display-hold function which allows the user to take a measurement in a difficult-to-reach location, remove the CP41 from the test site, and to bring it back into clear view still displaying its current reading.

The CP41 and CP410 meet the Safety requirements of EN61010-2-032:2002 and the EMC specifications of EN 61326-2-2:2006, and provide safe operation on uninsulated conductors carrying voltage of up to 300V with respect to ground. They measure 194 x 74 x 25mm, weight 235g, and operate for 15 hours from a standard 9V alkaline battery.

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