CHAPTER F CALIBRATION AND MAINTENANCE
F-1.
General
This section of the manual contains routine
maintenance information regarding the
AMPTEC RESEARCH Model 620A series
igniter tester. Calibration should be performed
on a regular basis to ensure continued
instrument accuracy or following a main PCB
electronic component repair/replacement. The
recommended calibration interval is 1 year.
The AMPTEC 620A series igniter tester is a
four wire Kelvin ohmmeter.
The 620A series
igniter tester must be calibrated using four
wire Kelvin connections to the resistance
standard
in order to eliminate lead resistance
and contact resistance errors. The Option “290”
has 48” long coax test cabling terminated with
twin single alligator clip jacks. One dual banana
plug (Voltage high and Current High) and one
other dual banana plug (Voltage low and
Current low) . The 4-wire configuration is
maintained up to the point of the alligator clip,
eliminating most cable resistance effects.
Typically 2m
W
of in series resistance is
associated with the AMPTEC “OP290" two
alligator clip lead set.
Note:
Only for 620 versions with a 2 Ohm
range:
the option "305" a 48" long replacement
cable set normally supplied as part of the
AMPTEC 620 package may have too much
resistance offset for the actual calibration of
620 Igniter Testers versions fitted with a low 2.0
Ohm range. Contact AMPTEC for information
on the “305” 48" long 4 wire Kelvin Calibration
Lead Set all terminated with single banana
jacks.
F-2.
Required Test Equipment
Following standard resistors are required to
calibrate the 620A-4R Igniter Tester .
Precision Resistors:
0.1 ohm ± 0.01% Accuracy
10 ohm ± 0.005% Accuracy
100 ohms ± 0.005% Accuracy
1000 ohms ± 0.005% Accuracy
10000 ohms ± 0.005% Accuracy
Test Leads:
AMPTEC Alligator Clip Test Lead Set
(OP290) or AMPTEC
Option "305")
F-3.
Calibration Procedure
The 620A series igniter tester should be
calibrated with fully charged batteries and
should be allowed to
warm-up
for a minimum
of
15 minutes
before beginning the procedure.
The calibration adjustments are accessed by
removing the 10 calibration access screws
around the perimeter of the 620A series igniter
tester front panel, then lifting off the top plate
by the handles. The locations of the
adjustments are shown on drawing number
620A-4R-600 at the back of this manual.
F-3-1. Zero Offset Adjustment
1.
Select the 20 ohm range. Connect the Kelvin
clips to the 0.1 ohm standard resistor.
2.
Adjust potentiometer RV2 for a display
indication of 0.100 .
F-3-2. Full Scale Adjustment
1.
Select the 200 ohm range. Connect the
Kelvin clips to the 100 ohm standard resistor.
Summary of Contents for 620A 4R
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