Daktronics 4000 Series Digital Billboard - Manual (Page 39)

T es ting the Dis play G round 33
S ection 10: Tes ting the Dis play G round
10.1 Tes ting with a G round Meter
1. Remove any molding covering the ground connection and provide sufficient room for
the jaws of the ground tester to close around the conductor.
2. Open the jaws of the ground tester and make certain that the jaws’ mating surface is
clean and free of dust, dirt, and other foreign matter.
3. Open and close the jaws a few times to allow the jaws to sit on the best mating position.
4. Set the rotary meter to .
5. When powering on the ground tester, the tester will calibrate itself to ensure accuracy.
Wait for the self-calibration to complete. During the process, the LCD will read, “CAL7,
CAL6,…, CAL2, CAL1.” Do not clamp to a conductor or open the jaws during
calibration. The tester will beep when the calibration finishes and is ready for use.
6. Test resistance by clamping the meter on the testing strip provided in the ground meter
kit. The testing strip simulates grounding rings and circuits. Once the reading is attained
from the test strip, remove the meter.
7. Clamp the meter to the electrode or the ground rod-bonding conductor that you are
measuring. Open and close the jaws a few times for better accuracy.
8. The LCD will read the ground resistance measurement. The meter will beep if the
resistance is less than 40 . The measurement should read under 25 . Record the
measurement.
10.2 Tes ting with a Multimeter
1. Remove any molding covering the ground conduction and provide sufficient surface to
contact the probes on the multimeter.
2. Turn the dial on the multimeter to the symbol.
3. Place the red positive probe of the multimeter on the ground wire in the term panel.
4. Place the black ground probe against the main distribution case.
5. The LCD will read the ground resistance measurement. The measurement should read
under 25 . Record the measurement.