Digital Throttle Control Operation And Adjustments - Vmac UNDERHOOD 70 Installation Manual

Digital Throttle Control Operation and
The VMAC digital throttle is a "slow ramp" throttle. Each time the
system is powered on, it will quickly increase engine speed to
1,500 rpm; then increase to maximum VMAC rpm over 8 seconds
(provided the system has not reached full system pressure before
maximum VMAC rpm is reached).
After the initial slow ramp, the throttle will respond normally to air
demand.
The throttle control is configured at the factory for optimum performance at
maximum cfm. In applications where maximum cfm is not required, or noise is a
concern, the throttle control can be adjusted to reduce the maximum VMAC rpm.
Safety features
The throttle control has built in safety features that will disable the system if an
unsafe condition is detected, or either of the lock out parameters is not met (the
vehicle must be in "PARK" and the park brake must be engaged).
If an unsafe condition is detected, the "STATUS" LED will turn off, and engine speed
will return to idle. Once all unsafe conditions have been removed, the system must
be cycled off, then on again to reset it. Once the system powers up, the "STATUS"
LED will illuminate, and the system will operate normally.
If the vehicle is placed into gear, the "STATUS" LED and the PRNDL
LED will turn off and the throttle control will deactivate. This will
reduce engine speed to base idle.
In order to activate the system again, re-engage the appropriate
lockout and cycle the VMAC "OFF" then "ON" via the control box.
52
Adjustments
Figure 59 — Throttle control
VMAC - Vehicle Mounted Air Compressors
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