Iveco N45 MNA M10 Installation Directive Manual page 49

MAY 2006
Revolution-counter calibration VDO
Figure 45
2
1
1. Calibration button -
2. Panel lighting lamp.
The tachometer enables different and independent calibration
methods: "PULSE" and "ADJUST"; there is also a further "PRECI-
SION CALIBRATION" procedure which enables the attainment
of the higher level of precision.
PUlse cAliBrATiOn
o Measure the external diameter of the (M) engine pulley
and of the (AL) alternator pulley and then apply the fol-
lowing formula to calculate the rotation impulses:
N (rotation impulses) = ————— x 6
o Interrupt the electric supply to the instrument, insert a
rod, possibly not made of metal, until the regulation but-
ton (1) is pressed and keep it pressed.
o Restart the electric supply to the instrument and check
that the messages "PULSE" and "ADJUST" are alter-
nately shown by the display.
o When the display shows "PULSE", release the regulation
button (1), wait for about 3 seconds and then check
that the display shows the message "P-" followed by a
numeric value.
o Input the numeric value N previously calculated as
shown.
o Wait for the flashing of the first figure on the right and
for the others in a sequence. The figure which flashes can
be modified by pressing the regulating button (1).
o When the calibration is finished, wait for a few seconds;
the display returns automatically to the counter func-
tion.
insTAllATiOn direcTiVe
2
06_003_N
Ø M (mm)
Ø AL (mm)
AdJUsT cAliBrATiOn
To be carried out through the comparison with a reference
instrument
o Supply electric power to the instrument and verify that
the display alternately shows the messages: "PULSE" and
"ADJUST".
o When the display shows "ADJUST" release the regula-
tion button (1) and then start the engine and take it to
a constant rotation speed.
o The display shows the messages "UP" or "dn" which
setS the regulation direction for the instrument index.
To select one of the two regulation methods - "UP" or
"dn" – press and release the regulation button (1).
o When the display shows the message "UP" the regula-
tion is carried out increasing, when the display shows the
message "dn" it is carried out decreasing.
o Register the rotation number through the reference
tachometer and compare it with the value shown by the
tachometer which is being calibrated. If necessary press
and keep pressed the regulation button (1) until the
required number is shown and wait for about 30 sec-
onds for the automatic RESET of the instrument, which
is shown by the fact that number of rotations on the
instrument index goes to zero and then goes up again.
PrecisiOn cAliBrATiOn
This procedure enables a regulation ± 20% better than the
value previously set.
o When the engine is rotating at a constant speed, press
the regulating button (1). The display shows the message
"A 0.0".
o Press and keep pressed the regulation button (1) to
make the displayed value increase in 0.5 % step.
o If the regulation button (1) is released for 2 seconds and
then it is pressed again, the calibration value goes down
in 0.5 % steps.
o When the required value is reached release the regula-
tion button (1) and wait for at least 5 seconds for the
settings carried out to be recorded. The display returns
automatically to the counter function.
Maintenance
Should it become necessary to replace a panel light, remove
the lamp holder from the rear part of the instrument (see
Figure 41).
N45 MNA M10
4
N67 MNA M15