ET4000 ET4500 nulling of test lead resistance

Martindale Electric

ET4000 ET4500 nulling of test lead resistance

Published: 9 June 2022 · Category: Technical articles

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ET4000 Series nulling of test leads Application Note Removing sources of error for low resistance NULL  The process for nulling test lead resistance is a simple but important process which can often be overlooked. When measuring the resistance of a circuit, if the test leads aren’t nulled, the resistance of the leads will also be measured in the reading. Below is a step by step guide explaining how to null out test lead resistance when using Martindale ET4000 Series multifunction testers. On completion the results are stored in the instrument for future use. Fig 1. Lead configurations for nulling. Lead Nulling Compensation is required to remove the test lead and To make it easier to connect all three leads and clips instrument resistance from the measured resistance. together and reliably null out their resistance, Martindale The lead compensation is very important in order to includes a nulling adaptor (TL178) with ET4000/4500. obtain correct results when measuring low resistances. There are two separate calibration values which are automatically stored after carrying out the nulling process: ◆ one for r1, rN, r2, R1+R2 and R2, ◆ one for R1+RN, R LOWΩ and CONTINUITY. There is a simple process for nulling the lead resistance which requires the three test leads to be connected to the instrument and shorted together. On completion of the process, a symbol is displayed on screen in the Continuity message field and the values are stored in the instrument’s memory until the...