have an insulator delrin spool that separates the
upper jaw from the lower jaw of the clip. With two
of the clips you have a 4 wire Kelvin connection.
The 601ES Explosive Safety DMM being a four
wire Kelvin resistance meter often time may have
and
leads
(disconnected) from in everything.
When nothing is connected in the four wire
resistance mode and if the leads aren't shorted
together the display may appear to wander (i.e.
"
"
). The
High Impedance DVM circuit must receive a
voltage signal/input to display the proper value.
For the 601ES Explosive Safety DMM this is not a
problem when
is shorted to
(2 wire method) and
is shorted to
.
The AMPTEC 601ES DMM Series of Safety
Meters all incorporate a constant current source
design that renders them incapable of delivering
excessive voltage or current to the device under
test. The fail-safe current (<10mA) for each range
is indicated section B of this manual. Please refer
to section
for a technical description of the
failsafe circuitry specifics.
It is important to avoid too many 2 wire adapters
and connections in series with the "resistance
under test" if possible. A
test wire
harness
or
or a
(i.e.
twisted pair) that is
can become a real
intermittent resistance measurement error problem.
A fatigued adapter or loose connector, plug, or
wire splice will often times changes their contact
resistance characteristics as the connection wiring
is handled. Loose adapters, connections, and
plugs, are potentially one of the largest source of
resistance measurement errors and should be
recognized and avoided. As a general rule, when it
comes to measuring electrical resistance,
you can make to the "device
under test"
If the
indicator
is displayed, the 601ES DMM readings should not
be trusted.
Voltage high
Voltage low sense
measure mode with nothing connected
Voltage high
Current
high
Voltage low
Current low
open
circuited
E-5
D-6. Fatigued Adapters and Loose Connections
- Common Sources of Measurement Error
D-7. Battery Monitoring Circuitry -
fatigued
adapter
wire/plug
wire splice
loose
the fewer
the connections
the fewer the problems.
The LCD
display
"
"
"
"
will indicate
when it is time to
replace the batteries.
LO BAT
LO BAT
The
The AMPTEC 601ES DMM Series of Safety
Meters all incorporate a constant current source
design that renders them incapable of delivering
excessive voltage or current to the device under
test. The fail-safe current (<10mA) for each
range is indicated section B of this manual.
Please refer to section
for a technical
description of the failsafe circuitry specifics.
The 601ES Explosive Safety DMM Igniter
Tester receives it’s power from an internal
re-chargeable battery pack - 4 “AA” batteries
housed behind its metal battery box.
When the lower portion of the LCD display
indicates
the AMPTEC 601ES
Explosive Safety DMM is in overrange mode.
Make sure the test leads are connected to the
“UUT”. The “Overrange State” can occur
whenever the measurement terminals are open
circuit (not connected to anything), or the
measurement under test is “higher than the
selected range. The most common way to
correct for an “overrange condition is to select
the next higher range. Of course if your already
at the highest resistance range, for example (20
kilo Ohm), then the instrument is informing you
that the
is a higher level
than 20 kilo Ohms, possibly an “open circuit".
D-8. Failsafe Operation Overview
E-5
“>>>OR”
Overrange Indication:
”
resistance under test
"
"
LO BAT
.
-
will typically come on when
the AMPTEC 601ES DMM internal batteries (4
ea. 1 5 VDC alkalines Duracell Ultra or better)
reach approx. 3.6 VDC. To change the batteries
remove the screws securing the battery compart-
ment. The back side of the battery compartment
cover is lined with a sponge fill neoprene gasket
to help provide a water resistant battery com-
partment. Carefully pull the battery holder out
and remove the cable-tie securing the batteries.
Observe battery polarity when replacing the
"AA" batteries. Re-secure the four new batter-
ies in the holder with a new cable tie, then
return it to the battery compartment and re-
secure the compartment lid (screws). See
Section A-4 for diagram.
Sect. D - Operation, Functional Self-Test and Use
15
