General Technologies TA100 SmarTach + : Digital Tachometer and Engine Analyzer - Manual (Page 5)

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3- Press and hold the (Engine Cycles / KV Adjust) button until the minimum reading
in the display is replaced by ‘KV Scale” and then a number followed by a ‘%’ sign, as
shown in Fig. 4 below.
4- While holding the (Engine Cycles / KV Adjust) button pressed, use the (Cylinder
Increase) or (Cylinders Decrease) buttons to adjust the scale value.
4.2 Wireless RPM measurement
This function allows to measure RPM without contact with any spark plug wire or any
other part of the engine, allowing quick and safe RPM measurement from a convenient
location.
1- Follow the procedure described in section ‘3.4.1.2 Wireless RPM measurement’,
and hold the SmarTach+ by its rubber holster. Do not touch the capacitive pickup or
flexible probe .
2- Place the flexible probe near (but without touching) a place were the spark plug wires
are grouped together, like a distributor cap, coil packs, etc. After a brief moment the
display should start showing the RPM of the engine.
3- If a different position of the instrument is required, move the flexible probe slowly away
from its position, while insuring the instrument is providing an steady RPM reading. If
you do move the flexible probe too quickly, the instrument will be unable to adjust to
the rapid changes, and it may not provide steady readings if any at all.
4- After obtaining the first reading, you may want to continue to move the flexible probe
further away, in order to locate the SmarTach+ in a more comfortable position or to a
convenient resting place (e.g. air filter, etc.). If while doing it, the display starts to show
“0”, then you have moved the flexible probe to a distance or place in which the signal
has become too weak to be detected by the instrument. Try moving the flexible probe
closer to the ignition system or rotating the SmarTach+, until the RPM reading
is reestablish.
Notes:
• In special cases where the ignition system is partially shielded by metal parts, the
working range of the SmarTach+ will diminish, and it may be necessary to move the
SmarTach+ flexible probe closer to the spark plug wires to obtain a reading.
• If the flexible probe is placed too close to the one of the spark plug wires, this individual
single spark plug wire signal may overtake (in strength) the signals form the other spark
plug wires, and the SmarTach+ will show the RPM divided by the number of cylinders
selected. This situation can be easily rectified by moving the flexible probe to another
location or setting the number of cylinders to ‘1’ in the SmarTach+.
• If you decide to lay the SmarTach+ down on a nearby resting place to have both hands
free to make adjustments, make sure that the capacitive pickup and flexible probe is
not touching any metal part and that engine vibrations cannot cause the SmarTach+
to move or fall.
4.3 Spark Plug Wire Peak Voltage Measurement
In addition to its primary function as a tachometer, the SmarTach+, has the capability to
indicate the relative strength of the spark plug wires peak voltage.
Checking the ignition system
1- Select the spark plug wire peak voltage function by following the procedures in ‘3.4.2
Spark Plug Wire Peak Voltage Measurement’.
2- The end of the flexible probe is provided with a special capacitive pickup with a groove,
designed so the spark plug wire is placed inside it. This capacitive pickup can be rotated
on the flexible probe to easily adjust to a convenient position. Place this capacitive
pickup over the spark plug wire, as near as possible to the spark plug, pressing gently
on the spark plug wire, while maintaining a right angle between the capacitive pickup
and the spark plug wire
Notes:
• By adjusting the Peak KVolt scale while performing spark plug wire peak voltage
measurements, it is simpler and easier to evaluate the changes and/or matching
other instruments readings.
• The scale can be adjusted between 20% and 200% of the factory calibration value
(i.e. 100% factory value).
• For example, if KV Adjust is set to 50%, the spark plug wire peak voltage shown will
be half (or 50%) of the value shown when using the factory default setting.
• The values set by using the KV Adjust function are stored in a permanent internal
memory, and will be retained even if the instrument is powered off, the battery is
depleted or is removed.
4. APPLICATION INFORMATION
4.1 Single cylinder RPM measurement
This function allows to measure RPM by using the capacitive pick up in a single spark plug
wire, in cases when it is difficult or not possible to position the TA100’s antenna in a place
where it can receive signals simultaneously from all the spark plug wires.
A few examples of where to use single cylinder RPM measurement are:
• Single cylinder engines.
• Engines with two banks of cylinders using one distributor and ignition coil for each bank.
• Spark plug wires, distributor, and ignition coil partially or totally shielded by metal parts.
Note:
• In order to obtain the correct RPM reading, insure the number of cycles is set to match
the cycles of the engine under measurement, and the number of cylinders is set to
‘1’ (for details on how to enter these setting see section ‘3.4.1.1 Single cylinder RPM
measurement’
) .
Cycles
Peak
%
Cylinders
KV Scale
Fig. 4 - Example of display when in KV Adjust mode