SOR Multi Point RF Level Switch - Manual (Page 6)

6/36 Form 677 (05.13) ©SOR Inc.
Probe Set up Overview and Considerations
If the process can easily be raised and lowered during set up, use the Actual Level Set
up procedure. During Actual Level Set up, the process must be positioned to maximum
level and to each set point level as briefly outlined in
. Begin the Actual Level Set up
procedure on page 8.
If the process cannot easily be raised and lowered during set up, use the Calculated Set
up procedure. During Calculated Set up, picofarad readings are taken at two levels.
The readings are used to calculate the picofarad value for maximum level as well as the
picofarad value for each set point level. Begin the Calculated Set up Procedure on page 9.
The Actual Level Set up procedure and the Calculated Set up procedure are designed
to yield maximum set point adjustability. In both procedures (Actual Level Set up and
the Calculated Set up), the active area of the probe is spanned to maximum process level.
(Step 1
) When the span is set to maximum vessel level, set point adjustability is
unlimited up to maximum vessel level ( ).
By spanning the probe only as high as the uppermost set point level (instead of maximum
level - see g g
), set point adjustability is restricted, but set point resolution is optimized.
To modify the Actual Level Set up procedure for optimal resolution, set the threshold for
probe span and the threshold for the uppermost set point while the process is steady at the
uppermost set point level. (See modification to Step 1
)
To modify the Calculated Set up procedure for optimal resolution, use the picofarad value
for the uppermost set point as the picofarad value for maximum level.
and
illustrate the effect of span on resolution. Note on that set points cannot
be positioned above the uppermost set point. If future requirements call for a set point that
is higher than the current uppermost set point, the probe will have to be re-spanned to the
new uppermost set point level (or to maximum level).
Units in Hazardous Locations — Prior to calibration, make sure that the
work area is declassifi ed before removing the explosion proof cover to
calibrate the unit. Failure to do so could result in severe personal injury
or substantial property damage.