Moog D680 Series - Electronics Logic Functions

47Rev. C, April 2017
BACKGROUND Moog D680 Series Proportional Control Valves
ELECTRONICS LOGIC FUNCTIONS
47
BACKGROUND
Rev. C, April 2017
Moog D680 Series Proportional Control Valves
ELECTRONICS LOGIC FUNCTIONS
The onboard electronics of D680 Series Proportional
Control Valves is equipped with several logic functions.
Short descriptions of these functions are given in the
following. For more detailed information, please refer to
the Moog technical note TN 435: “Description of Logic
Functions”.
Enable Input
The enable input is used to activate or deactivate the
valve while the electric supply is powered. If the enable
input is switched to HIGH, the valve is in normal operation
mode. If the enable input is switched to LOW, there are two
possible modes:
1. The main spool moves to the defined safe end position
P→A or P→B. Then the main spool is moved to its fully
opened position by hydraulic power (“open loop”). This
option is not possible with fail-safe option W.
2. The valve stays in closed loop control mode and gets
an internal command signal that moves it to its center
position. The external command signal is ignored.
Digital Outputs for Monitoring
The D680 Series Proportional Control Valves can be
equipped with monitoring functions. Valves with an
11-pole + PE connector have 2 digital outputs for
monitoring functions:
1. Valve Status Output
This output indicates whether the valve is operational.
If the supply voltage is sufficient and the enable signal
is HIGH, the valve status signal is also HIGH. If either
the supply voltage is below 18 V or the enable signal is
LOW, the valve status signal is LOW.
2. Error Monitoring Output
Two options are available for the error monitoring
output:
a) Spool control deviation monitoring: If the control
deviation of the spool controller is larger than a
certain threshold (default is 30 %) for a certain
time, the output is switched to LOW, which
indicates an error. As long as the control deviation
is within the threshold, the output is HIGH,
indicating normal operation. This is used to detect
if the main spool is stuck, e.g. due to contamination.
b) Spool position monitoring: This function monitors
whether the spool is within a certain position range.
As long as the spool is within this position range,
the output signal is HIGH. If the spool is outside
this range, the output is switched to LOW. This
can be used, e.g. for safety functions to monitor
whether the spool is within its overlap range or not.
Move spool to end position
Move spool to center position
-100 %
+100 %
Time
Time
Center
position
LOW
HIGH
Enable
Spool position
AP TA
-100 %
+100 %
Time
Time
LOW
HIGH
Enable
Spool position
Safe spool positions
Flow
Spool position
Overlap with tolerances
Monitoring window with
tolerances
Safe
spool position
with tolerances