620LK Operation and Maintenance Manual – Rev. J – Updated January 2020
Page 16
13231 Rooster Springs Rd.
Austin, TX 78737
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amptec.com
Zero Adjustment:
With a precision 0.001 Ω (1.0 mΩ
) resistance standard that’s
0.005% or better, connect 4-Wire Kelvin test jacks (630-304) to the AMPTEC 620LK
meter. Through the top far right rear panel hole, adjust the trim-pot (see above diagram
labeled zero) to make the meter read the exact value of the
.0 mΩ
laboratory standard
resistor (i.e
. ~1.00 mΩ
value will be displayed). Because of the autolock feature, you will
have to wait 5 to 10 seconds between adjustments and readings for settling and an
updated display of the measurement. The meter will continue to sample and hold, and
then resample as long as it senses any continuity.
Full-scale Adjustment:
Next,
connect the meter via the 630-304 test leads across a
precision 100 m
Ω
resistance standard which is a 0.005% or better accuracy resistance
standard. Adjust the full-scale pot, using the hole located to the top left of the rear panel
zero pot access hole (see above diagram labeled fullscale), until the display is the
actual value of the 100 m
Ω
resistance standard in milliohms (i.e. 99.97 m
Ω
if the
standard is actually 0.09997
Ωs
). Because of the autolock feature, you will have to wait
5 to 10 seconds between readings for settling and an updated display of the
measurement. The meter will continue to sample and hold, and then resample as long
as it senses any continuity.
Finally, connect the meter via the 630-304 test leads across a precision 1.0
Ω
resistance standard which is a 0.005% or better accuracy resistance standard. Allow a
few seconds for settling time. Keep in mind the meter autoranges up to the 2.0 Ω range
when measuring a value above 200 mΩ. Verify the meter is within 5 counts (± .005 Ω)
on a 1.0 Ω standard.
This concludes the adjustment procedure for the AMPTEC 620LK meter.
E-7.1 Recommended Calibration Standards
We recommend using our 630-304 4-Wire banana jack test lead set to calibrate the
620LK meter. If you are interested in purchasing a set of these leads, please contact
AMPTEC.
If you need to purchase resistance standards, we recommend using a reputable
manufacturer and insuring that all standards are N.I.S.T. traceable. AMPTEC currently
uses
AMPTEC has a full-scale calibration laboratory within its manufacturing facility, and has
the full capability to calibrate your product(s) for you. If you are interested in using our
calibration services, please see section E-2 on page 13.
E-8 PCB Removal
Removing the PCB from any of our products is strongly discouraged. If a user is going
to perform the task, they need be authorized and trained. AMPTEC provides a free PCB
replacement for products under warranty, and a small fee for non-warranty products.
Removing the PCB from the 620LK meter will void the product’s warranty and
calibration.
