Fluke 9107 - Manual (Page 39)

S
Activate new command.
8.7 Secondary Menu
Functions which are used less often are accessed within the secondary menu.
The secondary menu is accessed by pressing “SET” and “EXIT” simulta-
neously and then releasing. The first function in the secondary menu is the
heater power display.
8.8 Heating Power
The temperature controller controls the temperature of the well by heating or
cooling the well with the thermoelectric modules. The amount of heating or
cooling power depends on the temperature set-point of the well. This heating
(or cooling) power value may be estimated by watching the red/green control
indicator light or read directly from the digital display. By knowing the amount
of heating the user can tell if the calibrator is heating up to the set-point, cool-
ing down, or controlling at a constant temperature. Monitoring the percent
heater power will let the user know how stable the well temperature is. With
good control stability the percent heating power should not fluctuate more than
±1% within one minute.
The heater power display is accessed in the secondary menu. Press “SET” and
“EXIT” simultaneously and release. The heater power will be displayed as a
percentage of full power.
20.00 C
Well temperature
S+E
Access heater power in secondary menu
-12 Pct
Heater power in percent
Negative numbers indicate the well is being cooled. -100% means the well is
being cooled at maximum power. 0 means the well requires neither heating nor
cooling. 100% means the well is being heated at maximum power.
To exit out of the secondary menu press “EXIT”. To continue on to the propor-
tional band setting function press “SET”.
8.9 Proportional Band
In a proportional controller such as this, the heater output power is proportional
to the well temperature over a limited range of temperatures around the
set-point. This range of temperature is called the proportional band. At the bot-
tom of the proportional band the heating is 100%. At the top of the proportional
34 Hart Scientific
8 Controller Operation