MTS Landmark Tabletop - Manual (Page 106)

e) Define a 50%, 0.1 Hz sine wave command and allow the actuator to warm up for approximately one-half
hour.
f) After the warmup period, stop the test program.
2. Check for actuator movement to determine how to proceed.
Disconnect the servovalve cable and observe the actuator rod.
• If the actuator rod has no noticeable movement, the servovalve is at the null position and does not
need to be adjusted. Proceed to Step 4.
• If the actuator rod noticeably moves, the servovalve requires adjustment. Proceed to Step 3.
3. Set the adjuster pin.
This task describes the mechanical null adjustment procedure.
a) Insert a 3/32-inch hex key into the adjustor pin socket. For the location of the adjustor pin, see the
following figure.
Caution:
Excessive torquing may shear off the adjustor pin eccentric.
Do not apply more than 12 lbf-in. (1.36 N•m) of torquing force to the adjustor pin.
If the pin does not turn using very little force, proceed to Step C of this task.
b) Slowly rotate the adjustor pin until the actuator movement is reduced to a minimum, and then go back
to Step 2. If the pin does not turn using very little force, proceed to the next step.
c) Reduce system pressure to low pressure (refer to the appropriate controlling device product manual).
Slowly rotate the adjustor pin until the actuator movement is reduced to a minimum, and then proceed
to Step 4. If the adjustor pin still does not turn, proceed to the next step.
d) Ensure that system hydraulic pressure has been reduced to zero before proceeding. To do this, turn
off the hydraulic power unit and exercise the actuator until it stops moving. Turn off electrical power to
the controller.
e) Remove the hex key and insert a 3/8-inch offset wrench over the self-locking nut.
f) Insert a torque wrench with a 3/32-inch hex key head adapter into the adjustor pin socket.
g) Using the offset wrench, loosen (but do not remove) the self-locking nut.
106 MTS Landmark™ Tabletop Load Units Product Information
Maintenance