Yokogawa YVP110 - Manual (Page 41)

<6. Maintenance>
6-3
IM 21B04C01-01E
6.3.4 Tuning the Pressure Balance of
Control Relay
When you use a double-acting cylinder actuator,
adjust the pressure balance of the control relay, if
necessary.
The optimal point of pressure balance slightly differs
depending on the packing and load characteristics
of the cylinders used, but in general, approx. 50
to 90% of the supply air pressure is said to be
appropriate.
The pressure balance of the YVP110 is set to
approx. 75% at the time of shipment.
It is possible to reduce the hunting phenomenon
and air consumption by adjusting the balance
pressure.
However, if the pneumatic piping is connected to
the valve actuator, the pressure of a cylinder on one
side becomes higher, and the balance cannot be
maintained.
If you want to increase the balance pressure,
turn the screw for adjusting the balance pressure
(shown in Figure 6.6) counterclockwise. If you want
to decrease the balance pressure, turn the screw
clockwise. At this time, you do must not to loosen
the screw beside the adjustment screw.
Do not loosen this screw
100
0
OUT1 OUT2
Pressure balance point Output air
pressure
(%)
Servo Output
SUP
OUT1 A M
Control relay
Pressure balance adjustment screw
F0606.ai
Figure 6.6 Tuning the Pressure Balance of Control
Relay