SOR RF Continuous Level Transmitter - Manual (Page 5)

Form 837 (05.13) ©SOR Inc. 5/16
Bench Calibration
Electrical power must be disconnected from explosion proof models before
the cover is removed. Failure to do so could result in severe personal injury
or substantial property damage.

Remove the sensor. (Unscrew the sensor from the housing. Disconnect the ring
terminal or banana plug from the sensor end.)

Connect power and a current meter to the unit per . Connect a capacitor
substitution box (available from SOR) to the circuit to simulate the probe. Connect the
probe lead to one terminal of the capacitor substitution box, and connect the other
terminal of the box to the control housing. (See
) Use short connection wires to
eliminate any stray capacitance which may affect the calibration.

Set the capacitance box to desired zero level
capacitance.

Rotate ZERO and SPAN fine adjustment
potentiometers (pots) at least 22 turns
counter-clockwise.
Zero Adjustment (4 mA)

Close ZERO switch #1 and SPAN switch #1.
(See ) Open all other switches per .

View the reading on the current meter. If the
output is less than 4 mA, turn the fine ZERO
adjustment clockwise until 4 mA is reached.
NOTE: Only one ZERO switch may be in the closed position at any time.

If the output is greater than 4 mA, (opening the previous switch) close each coarse
adjustment switch, one at a time, until a reading less than 4 mA is reached. Turn the
fine ZERO adjustment clockwise until 4 mA is reached.
NOTE: If 4 mA cannot be obtained, please see the trouble shooting chart on page 14.
Span Adjustment (20 mA)

Set the capacitance box to the desired maximum capacitance value.

Ensure SPAN coarse adjust switch #1 is in the closed position, with all other switches open.

Rotate the SPAN fine adjustment pot clockwise until the meter indicates 20 mA. If a 20
mA reading cannot be obtained, proceed to step 11.
Open SPAN switch #1 (coarse) and close SPAN switch #2. Repeat step 10. If a 20 mA
reading cannot be obtained, repeat the procedure closing switch #3 or #4 until 20 mA
is indicated.
NOTE: Only one SPAN switch may be in the closed position at any time.
NOTE: If 20 mA cannot be obtained, please see the troubleshooting chart on page 14.
If the zero setting is changed, the span will change, and the unit must be recalibrated.
SORtrax
Ground Wire
Capacitor
Substitution Box
Probe Wire
Capacitance
Substitution
Connection