SOR Thermal Differential Flow Switch - Manual (Page 6)

6/12 Form 1024 (08.13) ©SOR Inc.
Calibration for Level Switches
For optimum operation, calibration must be accomplished at actual process
temperature and pressure conditions. Using
as a location guide, adjust the
system as follows:

Remove the instrument enclosure lid by turning it counterclockwise.

Apply power to the T21. Allow 5 minutes for the T21 to warm up. Verify J1 jumper is in
the level position (Factory Default).

Ensure that the tank liquid level is below the probe sensor tips and the tips are dry.

Set the trip adjust potentiometer to zero fully counterclockwise (ccw).

Adjust the dry adjust pot so that the red LED just illuminates. This is a 25-turn
pot. If the green LED is on, turn the pot counterclockwise (ccw). If Red LED is on,
turn the pot clockwise (cw).

Toggle the dry adjust pot back and forth until the switching point is well defined.
Leave the red LED illuminated. To ensure best definition/performance, wait
approximately 30 seconds between toggles.

Raise the level of the liquid to be detected until the probe/sensor tips are submerged
and wet (covered).

Set the trip adjust pot to 100 (fully clockwise).

Adjust the wet adjust pot so that the green LED just does illuminate. This is a
25-turn pot. If the green LED is on, turn the pot clockwise. If the red LED is on,
turn the pot counterclockwise

Toggle the set adjust pot back and forth until the switching point is well defined.
Leave the green LED illuminated. To ensure best definition/performance, wait
approximately 30 seconds between toggles.
Adjust the trip adjust pot to 80 and the calibration is complete.