GxT Ferret 92 Color Labscope - Manual (Page 13)

13 www.gxtauto.com
Tips & Techniques
You will fi nd addition information here that will help you make the best possible measurements. You do not need
to spend time trying to interpret a waveform that is the result of a bad connection or noise.
Setting the proper Time Base
You should adjust the time base to display one full cycle of the waveform on the screen at one time. Having more
than one complete cycle on the screen will make the pattern smaller than necessary and will cause you to spend
time looking at parts of the waveform that are not necessary. In the case of a Fuel Injector waveform you need a
time base that only shows one fuel injector waveform on the screen.
Setting the proper Voltage Range
The waveform should be displayed with the lowest possible voltage range without the pattern displaying an over
range indication. Any portion of the waveform that over ranges will be drawn in a light blue color. If you get a
waveform that is over ranging, simply increase the voltage range until the light blue trace goes away. Another
way view the voltage range is to increase the voltage range until you get an over range indication, then reduce the
voltage range.
Using the Channel 1 through 4 Test Leads
Each analog channel has a differential input. That means you have a ground lead and a sense lead for each channel.
Having a separate ground for each channel keeps outside noise to a minimum and protects the component being
measured on Channel 1 from being infl uenced to damaged by signals from any other channel. When you are looking
for a ground location, please ground the test lead as close to the test point as possible.
Using the Low Amps Probe
The low amps probe was designed for use on ignition circuits and for measuring low current draws. It is best used
in conjunction with other test techniques. Should you require a higher degree of resolution, you can connect any 3rd
party amps probe to the analog input channels. With this release of the software, there is no way to zero the amp
probe. If you want an absolute measurement, press HOLD and use the cursors for an accurate measurement.
Using the High Amps Probe
The High Amps probe was designed for use on starting and charging circuits. With this release of the software,
there is no way to zero the amp probe. If you want an absolute measurement, press HOLD and use the cursors
for an accurate measurement.
Using the Spark Pickup
The Spark Pickup will connect around any spark plug wire. This pickup must be used when using the Cylinder #1
or RPM trigger. The pickup should be connected to the spark plug wire with the spark plug side of the pickup fac-
ing the spark plug. If the RPM is not stable, fl ip the pickup over or move the pickup to the other end of the circuit.
If you are connected close to the spark plug, move the pickup close to the coil or distributor. If you are connected
close to the distributor or coil, move the pickup close to the spark plug.
Using the Ignition Adapter
The ignition adapter has the capability to test up to 10 cylinders. At the top of each row of inputs is a polarity switch.
This will help you get a good pattern on Distributor, C.O.P., or Double ended coil systems. On double ended coil
systems it is best if you connect two coils at a time to the adapter. Make sure the adapter is turned on and the
power indicator is illuminated. When using the ignition adapter, the KV readings will be 10 times the voltage. For
example if the voltage range is 1.5 volts, the maximum KV displayed would be 15 KV.
Power Leads
For the best possible pattern, power the analyzer from the vehicle’s battery. If you are unable to connect to a battery,
you can use an AC adapter to supply power to the unit. It is best not to use the AC adapter while testing engine
components with the engine running.