value or offset. Then when the 630ES leads,
including the in-series harness wiring
resistance, is connected to the test squib, the
squib test resistance can be calculated (via
subtraction of the 2 wire harness offset).
That is the 2 wire lead length shorted offset
resistance (without the squib resistance) can
be subtracted for the total resistance
(including the squib resistance) to
determine the actual squib (test) resistance.
The display should indicate a stable reading
when the test leads are securely attached to
the device under test. If the display appears
to be erroneous when connected to the
resistance under test, recheck the test leads
for integrity and cleanliness. If all external
items appear to be functioning properly, the
next step in troubleshooting is to use the
Function Test Section
of the AMPTEC 630
series igniter tester. The Functional Test
section contains test resistors of known
value. If a measurement problem appears on
the 20 Ohm range of the meter, test for a
zero offset problem first. Plug the test leads
into the 0.10 test resistor banana panel jack
built into the Functional Test Section of the
meter. If the meter doesn’t display a value
close to 0.1 Ohms adjust the zero knob on
the front of the meter until it does. The zero
adjustment knob only has enough span to
zero out the 630 series test leads. The
meter’s zero adjustment knob wasn’t
designed to zero out a 100 feet of 2 wire
harnessing.
The 10.0 Ohm test resistor is also located
Functional Test Section
of the meter. The
10.0 Ohm test resistor can be used for
testing mid-scale performance of the 20
Ohm range. Performing a similar Functional
Test with the meter across the 10.0 Ohm test
resistor should get a reading close to 10.0
Ohms (i.e
9.995
Ohms is OK). If the
630 series Igniter Tester appears OK after
checking the test resistors in the
Functional
Test Section
then the connect ion problem
must be outside of the 630 series meter (i.e
your wiring harness or the actual device
under test connection.) If the 630 series
meter doesn’t agree with the test resistors in
the
Functional Test Section,
then the meter
or it’s test leads are most likely broken. If
this case, please contact your local
AMPTEC RESEARCH Service Office, or
call 1-800-350-5105 or (512) 301-9333
(International Overseas) or FAX (512) 301-
9303, email
.
D-6.
Failsafe Operation
The AMPTEC 630 series of igniter testers or
failsafe ohmmeters incorporate a
constant
current source design
that renders them
incapable of delivering excessive voltage or
current to the device under test. The
typical
fail-safe current for each range is indicated
under the corresponding range switch on the
630 series meter front panel. Please refer to
section E-6 for a technical description of the
failsafe circuitry specifics.
As a further precaution the 630 series igniter
tester is isolated from the AC line
whenever the POWER switch is in the ON
position.
The 630 series igniter tester receives its
power from an internal rechargeable battery
pack (4 “D” Cell Ni-Cad batteries). The 630
series igniter tester main power switch (see
item 21 of the 630 series igniter tester
Front Panel Diagram) must be in the OFF /
CHARGING position in order to charge the
batteries. Of course, the battery charger must
also be plugged into the unit’s keyed single
access connector. As mentioned earlier the
630 series igniter tester ’s keyed single
access
front panel connector allows either
the slim-line battery charger to be connected
or
the 630 series igniter tester test leads to
be connected to the 630 series igniter tester
ohmmeter
but never both simultaneously
.
This “keyed single access front panel
connector”
safety feature
eliminates any
possibility of the operator measuring with
the 630ES Igniter Tester test leads while
also connected to an AC line powered
adapter.
