17
Automatic Control
APPENDIX B
Hydraulic Valve Guide
PC - Proportional Current Valve:
PC - Proportional Current Valve:
PC valves are proportional spool valves.
The maximum current supplied to the valve solenoid is equal to machine voltage divided by
coil resistance.
Pulse Width Modulation (PWM) is used to create the < 100% proportional current signal.
The PC signal energizes 1 coil at a time which slides the valve's spool back and forth changing
the valve's orifi ce size which changes the oil fl ow rate.
If the valve's maximum current rating is less than the maximum supplied current, (machine
voltage / coil resistance), use the PC valve current set mode (Appendix G) to lower the maximum
supplied current to within the valve's maximum rated current. Reference Appendix J for PC
valve identifi cation and control box settings.
Application Note: PC Valves are typically fast, but not always accurate.
Direct operated solenoid PC Valves are limited in fl ow rates to about 8 GPM (30 l/m) due to the
force capability of 12V solenoids.
PC Valve Wiring:
PC Valve Wiring: (P/N ATI-026040-XX)
Lower
Correction
Raise
Correction
On Grade
Deadband
0%
50%
100%
Valve Min.
Correction
Gain = 1 (Linear)
Gain = 1 (Linear)
Gain = 8 (Linear)
Gain = 8 (Linear)
Gain = F (Linear)
Gain = F (Linear)
PC Valve Signal
(% of Maximum Current)
Gain = 8 (Exponential)
Gain = 8 (Exponential)
Lower
Ground
A
B
C
D
E
F
G
H
I
J
Raise
Load Sense
Raise
Coil
Lower
Coil
M
CB
1
or
M
CB2
10-Socket
Connector
Blue
Green
Red
Orange
White
Black
White/Black
Switched Power
Ground
Not Used
