DESCO WEST
- 3651 Walnut Avenue, Chino, CA 91710 • (909) 627-8178
DESCO EAST
- One Colgate Way, Canton, MA 02021-1407 • (781) 821-8370 • Website:
Desco.com
TB-3078
Page 5 of 6
© 2019 DESCO INDUSTRIES INC
Employee Owned
3.5 megohms
1. If the desired resistance is 3.5M, jumpers JP1 (MAT
1 and JP2 (MAT 2) need to be on one pin (see
Figure 5).
2. The respective potentiometers need to be adjusted
fully clockwise. The pots are located inside the unit
on the bottom board (see Figure 6).
High Resistance (10 kilohms to 3.5 megohms)
1. If the desired resistance is 10k - 3.5M, jumpers JP1
(MAT 1) and JP2 (MAT 2) need to be on one pin
(see Figure 5).
2. Use a resistor decade box to set the desired
resistance between the ground terminal and ground.
3. Connect the mat wire to the decade box and
connect the decade box to ground.
4. Turn the appropriate potentiometer
counter-clockwise until the GROUND LED
illuminates red and alarm sounds (see Figure 6).
5. Slowly turn the potentiometer clockwise until the
GROUND LED illuminates green.
6. Add 10% more resistance (at least 1 ohm) to the
decade box and verify that the GROUND LED
illuminates red and alarm sounds.
7. Return back to the starting resistance and confirm
that the green LED illuminates again. Repeat steps
4-7 if the monitor does not fail with the increased
resistance or return to a pass condition.
Low Resistance (<1 kilohm)
1. If the desired resistance is < 1k, jumpers JP1 (MAT
1) and JP2 (MAT 2) need to be on both pins (see
Figure 5).
2. Use a resistor decade box to set the desired
resistance between the ground terminal and ground.
3. Connect the mat wire to the decade box and
connect the decade box to ground.
4. Turn the appropriate potentiometer
counter-clockwise until the GROUND LED
illuminates red and alarm sounds (see Figure 6).
5. Slowly turn the potentiometer clockwise until the
GROUND LED illuminates green.
6. Add 10% more resistance (at least 1 ohm) to the
decade box and verify that the GROUND LED
illuminates red and alarm sounds.
7. Return back to the starting resistance and confirm
that the green LED illuminates again. Repeat steps
4-7 if the monitor does not fail with the increased
resistance or return to a pass condition.
Calibration
Frequency of recalibration should be based on the
critical nature of those ESD sensitive items handled
and the risk of failure for the ESD protective equipment
and materials. In general, Desco recommends that
calibration be performed annually.
Use the EMIT
50524
Limit Comparator to perform
periodic verification (once every 6-12 months) of the
Zero Volt Monitor Monitor. The verification tester can
be used to check the test limits of the Zero Volt Monitor
without removing it from the workstation.
See
TB-6542
for more information.
Figure 7. EMIT 50524 Limit Comparator
