Subject to change without notification
Subject to change without notification
3.8 Pointer Mode
26
Operation in pointer mode is selected by the command
ptrmod
(ptr = pointer). This mode is
used to simulate an analog pointer instrument. In this case, the rotor moves in steps of 1/256th
of a revolution, to a position proportional to the analog voltage applied at the control input.
In this way, an applied voltage of 0V corresponds to a rotor position of about 0 degrees.
5V will set the rotor to about 350 degrees.
Using
ptrfac
and
ptroff
, the angular deflection is linearly modulated.
ptrfac
sets the factor by
which the measured analog signal will be multiplied, before the rotor position is calculated
from it. The value 100 corresponds to an amplification of 1,00.
ptroff
is added to the rotor
position. This leads to the following formula:
Limits:
The input
AUXin
is protected by grounding with a 5.1V Zener diode. Since this starts
to operate at about 4,0V, it creates non-linearity distortions in the upper range of voltage.
To achieve high linearity, input variations should therefore avoid this range.
Voltage
ptrfac
Angle =
.
255 +
ptroff
5V 100
.
