3.3
Mode (tell-tale at 2)
The following table shows the value to set for the mode:
Mode
Tell-Tale
Trigger Pulse
Chromometric
0
Auto reset
Negative
No
1
Manual
Negative
No
2
Auto reset
Positive
No
3
Manual
Positive
No
4
Auto reset
Negative
Yes
5
Manual
Negative
Yes
6
Auto
Positive
Yes
7
Manual
Positive
Yes
Tell-Tale Modes
The tell-tale needle on original chronometric tachometers was mechanically pushed to the highest
reading reached by the main hand. The tell-tale could be reset by pushing a small button on the
side of the instrument. This is copied in the manual reset mode. The auto reset mode resets
the tell-tale hand after about two seconds back to follow the main hand. This is very useful as it
gives the driver time to see what the engine was revved to before or during each gear change.
Trigger Pulse Polarity
This may need to be changed to match the pulse from a special sensor. For ignition coil
connected wiring set it to positive.
Chronometric Action
If this option is selected with settings 4,5,6 or 7, the tacho moves the main needle once every half
second in the manner of the original mechanical chronometric movements. This action is
switched off after reaching 5000 rpm for 0 to 8,000 and after reaching 6,000 rpm for the 0 to
10,000 and 12,000 versions.
Once you have adjusted the mode setting, hold the push button pressed for five seconds.
3.4
Trigger Pulse Filter (tell-tale at 3)
The trigger pulse filter sets the shortest electrical pulse to which the tacho will respond. For
ignition connected wiring, set this to 7 and only reduce it if the tacho does not read over a certain
rpm. For special sensor systems, set this to 1 as a first try. If the needle starts to jump up when
the engine is running under load, try increasing the filter setting.
After setting the filter, push the button for 5 seconds to save the setting
