VA-8122 Proportional Valve Actuator Product/Technical Bulletin
5
Direction of Action
The actuator’s direction of action is selected with
Jumper W2. (See Figure 3.) The action of the actuator
can be reversed by moving Jumper W2 on the circuit
board. When Jumper W2 is in the DD position (factory
setting), a low control input signal will cause the
actuator lever arm to move to the highest position
(valve stem up). A high control input signal will cause
the actuator lever arm to move to the lowest position
(valve stem down). When Jumper W2 is in the
DU position, the lever arm will be low for a low control
input signal and high for a high control input signal.
(See Figure 7.)
DU Mode
DD Mode
Low Control
Input Signal
Stem
Down
Stem
Up
Signal Increase
High Control
Input Signal
Figure 7: DD/DU Direction
The DD mode will result in the Direct Acting (DA)
operation of a Push-Down-To-Open (PDTO) valve.
Auto Calibration
The VA-8122 is factory calibrated for a 5/16 in. valve
stroke. To compensate for minor variations in strokes,
use the Auto Calibration or AUTOCAL mode during the
calibration and installation of the actuator. This mode
allows the actuator to define the control input range
proportionally over the valve stroke stored in
nonvolatile memory (retains data when power is lost or
removed).
Note:
Once calibrated, it is not necessary to
recalibrate if a jumper is changed.
To activate the AUTOCAL mode, depress the
AUTOCAL pushbutton for approximately 3 seconds
until the LED turns off. The actuator drives to the
DU end-stop, then to the DD end-stop, and stores
these positions in nonvolatile memory. The actuator
will drive to the setpoint determined by the control
signal applied after going through AUTOCAL.
Note:
AUTOCAL mode only occurs when the
pushbutton is depressed. It does not occur
automatically when power is supplied to the
actuator.
LED
The VA-8122 has a green LED display to indicate the
actuator’s operating mode. (See Table 4.)
Table 4: Operating Display
LED Indication
Description
On Solid
Power is applied; actuator is at
setpoint or stalled (not driving).
Single
Blinking
Power is applied; actuator is
driving down or up.
Fast Single
Blinking
Insufficient supply voltage
Double
Blinking
Actuator is driving during the
Auto Calibration mode
(AUTOCAL pushbutton released).
Off
Power is not applied or Auto
Calibration mode is initiated
(AUTOCAL pushbutton
depressed for 3 seconds).
