Black Box Cable Length Meter, CLM5000 manual Set Length Mode screen

Chapter 4: Using the Cable Length Meter

Example: The factory default for Network wire is .0273 ohms per feet. Press the MODE key to select Network mode.

Press the SET LEN (LEN = Length) key, and a new screen will pop up (see Figure

4-4). In this mode, use the UP/DOWN keys to adjust the larger digits to match the length of the sample wire (100–200 feet range). If the sample wire is 150 feet and its resistance is equal to .315 ohms, the smaller digits on the left hand side of the screen will display “002.1mΩ”.

To store the new value, press the SET LEN key for approximately 1.5 seconds. The unit will generate a confirmation beep. The unit stores the new network length coefficient of .0021Ω per feet in memory.

Figure 4-4. Set Length Mode screen.

NOTE: Restoring Factory Default Values. To restore ohms per feet factory coeffi- cients back to their original values, hold the Power and UP/DOWN keys down at the same time while powering down the unit. Any previously stored values will be overwritten by the factory default values.

NOTE: To obtain symmetrical test results for Shorts and Opens measurements, the Cable Length Meter must have the correct “capacitance per feet coef- fiecient” and “resistance per feet coefficient“ of the wire under test.

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