Johnson Controls VFD66 Series Product/Technical Bulletin page 11

RPM
100%
Curve A
P1=40%
P2=CCW
50%
40%
Idle
30%
0%
Minimum
Motor Speed
Set by P1
Pressure or Temperature
Figure 14: Standard Input Mode
Electronic Pressure Transducer Input Mode
IMPORTANT: Minimum motor speed and motor
action at minimum speed cannot be set in this mode.
The VFD66 controls work with any electronic pressure
transducer that generates a 0-5 VDC or 0-10 VDC
output signal. For best results, use the P399 Electronic
Pressure Transducer or another ratiometric
transducer. A ratiometric transducer varies the signal
voltage from 10-90% of the 5 VDC supply power as
the pressure goes from minimum to maximum of the
transducer rating.
J3 establishes the low or high pressure range of P1.
See Table 11.
J7 establishes the voltage range of the transducer.
The J7 jumper must be installed when using a
P399 pressure transducer or another 0-5 VDC
electronic pressure transducer. The J7 jumper must be
removed when using 0-10 VDC electronic pressure
transducers.
Table 11: Electronic Pressure Transducer Input Mode
J2 Jumper J3 Jumper
Position Position
Removed Installed
Removed Removed
Removed Installed
Removed Removed
Removed Installed
Removed Removed
Removed Installed
Removed Removed
Removed Installed
Removed Removed
Curve B
P1=30%
P2=CW
Curve C
P1=0%
P2=CCW or CW
Proportional Band
Setpoint
P1:
Setpoint Range
16-44 psi
40-70 psi
32-88 psi
80-140 psi
80-220 psi
200-350 psi
120-330 psi
300-525 psi
16-44% of range
40-70% of range
VFD66 Series Condenser Fan Speed Controls Product/Technical Bulletin
P1 adjusts the pressure setpoint and establishes the
pressure value at which the VFD66 controls drive the
fan motor at maximum speed.
P2 adjusts the proportional band over which fan motor
speed is controlled.
Figure 15 illustrates J3, P1, and P2 settings in
Electronic Pressure Transducer Input mode with a
P399 transducer (0-500 psi). If the jumper on J3 is in
the removed position, P1 adjusts the setpoint between
200-350 psi. The fan motor starts when pressure
reaches 200 psi (Setpoint – Proportional Band) and
maximum motor speed (100% RPM) is reached at
250 psi (Setpoint).
RPM
100%
50%
(200 psi)
Figure 15: Electronic Pressure Transducer Input
Mode, 0-500 psi P399 Transducer
P2: Pressure Range
Proportional
Band
5-20 psi
10-40 psi
25-100 psi
38-150 psi
5-20% of range
Proportional Band
Set by P2
25–100 psi
(50 psi)
Set by P1 and J3
Electronic
Pressure
Transducer Model
Numbers
0-100 psi P399AAA-1C
P399AAC-1C
0-200 psi P399GAA-1C
0-500 psi P399BAA-1C
P399BAC-1C
0-750 psi P399CAA-1C
P399CAC-1C
Unknown
(250 psi)
Pressure
Setpoint
Other
11