SOR Multi Point RF Level Switch - Manual (Page 11)

Form 677 (05.13) ©SOR Inc. 11/36
All Models
The capacitor substitution box will inject capacitance, emulating the probe.
Using the thumbwheels on the capacitor substitution box, gradually increase the injected
capacitance until the probe loading LED lights.
Note the value on the substitution box thumb wheels when the probe loading LED lights;
record that value on line 4 of the worksheet. The recorded value is the picofarad value for
level A (2200 pf on page 12).
Take the alligator clip off of the probe lead, and plug the probe lead back into the probe.
Lower the process to Level B, and turn both DIP switches off (open).
Set Threshold for Level B Watch the probe loading LED:

LED is on — close DIP switch 1 and go to step 2.
LED is off — go to step 3.

LED is on — close DIP switches 1 & 2 and go to step 3.
LED is off — go to step 3.

Turn the span pot CW until the probe loading LED lights, and then CCW to the point
where the LED goes off.
Slowly cycle the LED on and off as required to find the precise threshold at which the LED
goes off. The instrument is now tuned to the picofarad value for Level B.
Find Picofarad Value for Level B
Unplug the probe lead from the probe. Clamp the alligator clip to the mini-banana plug on
the end of the probe lead wire. (The other alligator clip should still be clamped to ground.)
Gradually increase the injected capacitance until the probe loading LED lights.
Note the value on the substitution box thumb wheels when the probe loading LED lights;
record that value on line 5 of the worksheet. The recorded value is the picofarad value for
level B (1900 pf on page 12).
Using the picofarad values for A and B, the picofarad per foot value can be interpolated,
and the picofarad value for maximum level can be extrapolated as shown in p
. Complete
the worksheet to find as many set point pf values as applicable.
Leave the alligator clip on the probe lead wire. The capacitor substitution box will be used
to inject the calculated values from the worksheet.