Cable Length Meter
4.3 Coax, Network, and Telco Modes
Coax, Network, and Telco modes detect the distance to opens and the distance to shorts.
The Cable Length Meter determines the length by measuring line capacitance when the line is open or by measuring resistance when the line is shorted. When measur- ing opens, use the UP/DOWN keys to adjust the capacitance coefficient (10 to 40 pf per feet) to calculate the cable length. The Cable Length Meter supports three user-adjustable length coefficients, one for each type of cable (Coax, Network and Telco). It stores these coefficients in memory even when the unit is powered off.
Short/Resistance coefficients are stored in memory (see Table 4-2 for factory default values). These values can be changed by running the Set Length Function. The Set Length function allows the user to change factory default values, ohms per feet coefficients, based on a sample known length of wire. Press the SET LEN key to toggle between Normal Measuring screen (Figure 4-3) and Set Length Mode screen, Figure 4-4. In Set Length mode (line shorted), the unit will measure the resistance of the sample wire. Adjust the length of the sample wire using the UP/DOWN keys in the range of 100 to 200 feet. The smaller digits display the ohms per feet based on the sample wire. Press and hold the SET LEN key down for a few seconds to store the new coefficients.
Figure 4-3. Normal Network Measuring screen.
Page 16 | 724-746-5500 blackbox.com |
