Johnson Controls VFD66 Series Product/Technical Bulletin page 9

Selecting an Input Mode
See Table 6 for the available input mode options for
the VFD66 control. The factory–set mode is Manual
Input mode.
Manual Input Mode
Manual Input mode allows the user to set a constant
motor speed. This can be used where manual control
is desired or while repairing input signal devices or
obtaining replacements. In Manual Input mode, the input
device signals are disregarded. Motor speed is controlled
by adjusting the P1 potentiometer. Potentiometer P2 is
disregarded and adjusting P2 has no effect.
Table 7: Manual Input Mode
J2 Jumper J3 Jumper
Position Position
Installed Installed
Standard Input Mode
Standard Input mode is the most commonly used
mode. The majority of input devices compatible with
the VFD66 controls are used with this mode. The input
device determines the setpoint and proportional band.
Table 8: Standard Input Mode
J2 J3
Jumper Jumper
Position Position
Installed Removed
P1 adjusts the minimum speed of the motor. The
minimum speed is adjustable from 0 to 50% of total
motor speed. Turning P1 Clockwise (CW) increases
minimum speed setting, Counterclockwise (CCW)
decreases minimum speed setting.
P2 determines whether the motor idles at minimum
speed or shuts off at minimum speed. P2 must be set
at full CCW or full CW position; intermediate settings
have no effect.
P1: P2:
Motor Speed Not
Used
Adjusts constant —
speed of motor
(0-100%)
P1: P2: Motor
Minimum Action at
Motor Minimum
Speed Speed
Can be set at CCW:
0-50% of Motor idles.
maximum
CW: Motor
motor speed.
shuts off.
VFD66 Series Condenser Fan Speed Controls Product/Technical Bulletin
Figure 12 illustrates three possible motor speed
curves. When P2 is rotated fully CCW, the motor idles
at the minimum speed set by P1 at input values below
the end of the proportional band (Curve A in
Figure 12). When P2 is rotated fully CW, the motor
shuts off at the minimum speed set by P1 when the
input is below the bottom end of the proportional band
(Curve B in Figure 12).
In Curve C, the minimum motor speed (P1) is set at
0% of maximum motor speed and the position of
P2 has no effect.
RPM
100%
Curve A
P1=40%
P2=CCW
50%
40%
Idle
30%
0%
Minimum
Motor Speed
Set by P1
Pressure or Temperature
Figure 12: Standard Input Mode
Curve B
P1=30%
P2=CW
Curve C
P1=0%
P2=CCW or CW
Proportional Band
Setpoint
9