Cropico DO4A Portable Milliohmmeter

This portable digital ohmmeter is a practical instrument for low resistance measurement, ideal for use in the workshop, field or test facilities. It is of rugged construction contained in an aluminium case with tilt handle. The Cropico DO4A has many advanced features, including protection up to 415 volts rms, digital calibration and long scale length, 4,000 count. The rechargeable sealed lead acid battery means real portability with more than 14 hours continuous operation, without the problems normally associated with other battery types. Full measurement capability is maintained whilst charging. Simple push button selection of the range required ensures the DO4A may be easily used by unskilled personnel, error and status warnings are illuminated when appropriate. The utmost care has been used to ensure that the ohmmeter will withstand an accidental mains voltage applied to the measuring terminals, but it is not recommended that voltage should be applied. The measurement is true 4 terminal, using the Kelvin principle. A stable current is produced across the resistance to be measured via the C terminals, and the voltage drop across the Rx is measured at the P terminals. This potential drop is then compared against the voltage drop across internal standards, the ratio of these is then converted to the resistance value of Rx and displayed in ohms on the digital display. FEATURES True 4 wire measurement eliminates lead resistance errors. 6 push button ranges 40mΩ - 4kΩ with long scale length. 10µΩ resolution on 40mΩ range. Input protection up to 415Vrms. Zero control thermal E.M.F. compensation. Digital calibration. Mains/rechargeable battery operation. Open circuit lead warning. Rugged industrial maintenance free design. Cropico DO4a Specifications Range Resolution Typical Current Accuracy @20°C +5°C 1 Year Temperature Coefficient (°C) 4kΩ 1Ω 100µA +(0.05% Rdg + 0.02% FS) 30ppm Rdg + 1ppm FS 400Ω 100Ω 1mA +(0.05% Rdg + 0.02% FS) 30ppm Rdg + 1ppm FS 40Ω 10Ω 10mA +(0.05% Rdg + 0.02% FS) 30ppm Rdg + 1ppm FS 4Ω 1mΩ 10mA +(0.05% Rdg + 0.03% FS) 30ppm Rdg + 4ppm FS 400mΩ 100µΩ 10mA +(0.05% Rdg + 0.05% FS) 30ppm Rdg + 25ppm FS 40mΩ 10µΩ 100mA +(0.05% Rdg + 0.05% FS) 30ppm Rdg + 25ppm FS General Specifications Measurement 4 terminal Kelvin/Thomson principle eliminates errors due to lead resistance. Display 15mm LCD 4000 count with automatic decimal point and polarity indication. Ranges 6 push button selected with LED indication. Terminals 4mm binding posts accept spade tags and 4mm banana plugs. Mains Supply 100, 120, 220 and 240V +10 to 13% 47 to 63Hz 20VA. Safety EN 61010-1 EMC 61326. Calibration Digital security key protected. Auto Zero Permits the automatic zero of amplifiers and external circuits, eliminating errors due to thermal EMF. Protection 415V rms maximum at the measuring terminals will blow internal protection fuse. Battery 6V, 2.8Ah sealed lead acid battery with built-in charger. 14 hour typical operating time on lowest range, 28 hours typical on other ranges. Internal charger and automatic switch off. Working Temperature 0 to +40°C with relative humidity 80% max non-condensing. Storage Temperature -20 to +50°C. Dimensions 15 x 250 x 88mm (w x d x h) approx. Weight 3.5kg. Cropico DO4a warranty 1 year (subject to registration with Seaward).

For more information on Cropico DO4A Portable Milliohmmeter talk to Cuthbertson Laird Group