Deactivating And Activating The Tight-Closing Function; Version With Limit Switch - Adjustment - Samson 3372 Mounting And Operating Instructions

6. Adjust the potentiometer for span (10.1)
until the upper range value is correct.
Turn the adjuster clockwise to increase
the travel and counterclockwise to reduce
it.
7. After the correction has been completed,
increase the input signal again. Check
the starting point (20 mA) and the upper
range value (4 mA).
8. Place the protective cap back on the zero
adjuster.
9. Plug jumper back on the pins again to
activate the tight-closing function.
EB 8313-1 EN
6.2 Deactivating and activating
the tight-closing function
The electronic deactivation and activation of
the tight-closing function integrated in the
actuator ensures tight closing of the control
valve whenever the control signal exceeds or
falls below the switching point.
Actuator stem extends
If the reference variable falls below the
switching point of 4.08 mA ±0.14 mA hys-
teresis, the actuator is fully vented to close a
globe valve.
Actuator stem retracts
If the reference variable exceeds the switch-
ing point of 19.95 mA ±0.14 mA hysteresis,
the actuator is fully filled with air to close a
globe valve.
Î The tight-closing function is activated
when the jumper is plugged in. Remove
the jumper to deactivate this function.
6.3 Version with limit switch —
Adjustment
See Fig. 6-3
1. Undo the clamps of the stem connector
on the valve. Replace the front clamp
with the clamp including the U-bolt from
the accessories.
2. Move the valve to the switching point at
which the contact is to be activated.
Start-up
6-5