MacDon FlexDraper FD75 - Adjusting Voltage Limits

214323 137 Revision B
4.4.2 Adjusting Voltage Limits
Setting the voltage limits establishes the operating range of the auto header height control (AHHC) sensor with the
combine, allowing the combine to react to the float system’s feedback.
NOTE:
The auto header height control (AHHC) sensor assemblies used for CLAAS and some New Holland combines are slightly
different from sensor assemblies used for other combine models—all three assemblies are illustrated in this procedure.
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A
B
Figure 4.11: AHHC Sensor Assembly for Use with
CLAAS Combines
1. Complete the following steps to adjust the high
voltage limit:
a. Extend the guard angle fully. The header angle
indicator should be at D.
b. Position the header 152–254 mm (6–10 in.) above the
ground. The float indicator should be at 0.
c. Loosen sensor mounting bolts (A).
d. Slide sensor support (B) to the right to increase the
high voltage limit or to the left to decrease it.
e. Tighten sensor mounting bolts (A).
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A
B
Figure 4.12: Most Common 5 Volt AHHC Sensor
Assembly
2. Complete the following steps to adjust the low
voltage limit:
a. Extend the guard angle fully. The header angle
indicator should be at D.
b. Fully lower the header on the ground. The float
indicator should be at 4.
c. Loosen mounting bolts (A).
d. Rotate sensor (B) clockwise to increase the low voltage
limit, or counterclockwise to decrease it.
e. Tighten sensor mounting bolts (A).
AUTO HEADER HEIGHT CONTROL