Fluid Components International FLT Series - Manual (Page 20)

FLUID COMPONENTS INTL CHAPTER 3 - OPERATION
FLTÔ Series FlexSwitchÔ 3 - 2 Doc. No. 06EN003246 Rev. B
Figure 3-1. 5294 Control Circuit Jumper Locations
The reason for operation in the above extreme conditions is that the input signal range is at the widest point making
the alarm set point adjustment easier to perform. If the heater does cycle the operator may need to use the next lower
wattage setting.
In some applications it is desirable to set the heater wattage high, even though the sensing element goes into the
heater cutoff mode. An example is when the instrument is used to detect the interface of two liquids. These liquids
may have viscosities that will have signals very close to each other. In order to have the maximum signal difference
between the signals the heater wattage is set to its maximum. If the sensing element detects a dry condition the
control circuit will indicate a heater cutoff condition. The sensing element will not be dammaged if it is left dry with
the maximum heater wattage. The alarms can be set so one alarm will switch at the interface and one alarm can
detect when the element goes dry.
Alarm Set Point Adjustments
Numerical Adjustment Versus Adjustment by Observation
An alarm set point is established using either numerical adjustment or adjustment by observation. The adjustment by
observation requires the customer to establish normal process operation and adjust the alarm set point relative to this
condition. The numerical approach requires measuring normal and alarm process conditions with a voltmeter and
setting up the instrument in the calibrate mode based on these values. The adjustment by observation requires less
time to establish the alarm set point. The numerical adjustment requires control of the process as well as additional
time to establish the alarm set point. Use the adjustment procedure that is the most appropriate for the application
requirement.