10
Automatic Control
CONTROL BOX - CONFIGURATION
If auxiliary valve drivers and remote switches are desired, please consult the factory. Auxiliary
valve drivers can be used via remote switches to drive other functions like scraper bowl eject,
gate open and close, etc.
Once the proper valve is selected, perform a system communication check. Turn the box on to
confi rm power. Check that the receiver is communicating properly. Check the raise/lower and
auto/manual switches. Check the remote switch functions if installed.
Check for proper hydraulic system operation. Ensure there are no leaks, excessive engine load
or pressure relief valves continually opening. Check that all circuits function properly.
NOTE:
Before proceeding, warm up the hydraulic system to operating temperature.
Run the machine at operating RPM for approximately 15 minutes while cycling the
blade lift cylinder.
Valve Set Up (1
VV
4)
-
Set Valve Minimum Correction
The Valve Minimum Correction (VMC) is set to provide output fl ow as soon as a correction signal
is received providing for optimum system performance
ff
.
The edges of the valve spool have some degree of overlap with the corresponding edges of the
valve body ports. This is required to prevent fl ow across the spool when it is in a neutral position.
This spool overlap means that there will be a defi ned movement of the spool in the bore before
fl ow begins to take place. This characteristic is sometimes referred to as valve “deadband”. In
this text, adjusting the control box to account for this deadband and create a minimum blade
velocity will be referred to as the Valve Minimum Correction (VMC) to avoid any confusion with
laser system deadband or accuracy.
Spool Overlap - Minimum distance
to move valve for fl ow to begin.
The VMC is adjusted by using the LED Counter Switch as described in Appendix D. Adjustment
is made for both the raise minimum correction and the lower minimum correction.
The VMC for PT valves is adjusted in increments of time. The VMC for PC or PV valves is a
percentage of maximum valve correction.
Valve Type
Valve Type
VMC Increment
Adjustment Range
Adjustment Range
PT
10 ms
0 - 310 ms
PC, PV
2% of max.
0 - 62% of max.
