CHAPTER 3. OPERATION
Below the power switch you find the control over the feedback loop. The phase knob
can be used to reset the phase feedback in case that is has unlocked. The colour of the text
on the phase knob shows if the phase is correctly locked or not. When the text ”Phase”
appears in green than the phase is correctly locked. In case the text appears in red the
phase should be reset by the user by simply pressing the button. The amplitude switch
below the phase feedback knob can be used to turn the amplitude feedback function on
and off. Please note that the power can only be controlled when the amplitude feedback is
turned on. The user sets the power setpoint and the loop electronics will adjust the power
to reach the setpoint, in case the amplitude feedback loop is turned off the power will thus
not be changed.
The chiller icon, see figure 3.2, can have three colours. Red means that the chiller has
an error. Yellow means that the chiller is operating Ok but that the cavity temperature is
not equal to the temperature setpoint. Blue means that the cavity temperature is equal to
the temperature setpoint. The cooler icon can also be pressed to open the cooler window
that shows the temperature setpoint, the cavity to which this setpoint belongs, and an
graph of the temperature as a function of time.
Figure 3.2: Different states of cooler icon
Right to the chiller icon the transmitted power graph is shown. This graph shows the
amount of power transmitted to the cavity. The actual value is also printed in text (blue)
on top of the graph. The red text displays the reflected power. This value should be as
small as possible. When increasing the RF output power the cavity will start to warm
up, the chiller icon will become yellow. The heating of the cavity will cause the resonant
frequency to shift which means that the reflected power will increase. It will take some
time for the chiller to find a new equilibrium and you will see that the reflected power will
decrease over time. In steady state (blue chiller icon) the reflected power should be smaller
then 5 percent of the transmitted power. For example when 10
.
0 W is transmitted the
reflected power in steady state should be
<
0
.
5 W.
The phase and power dials on the top are used to control the output. These values can
be changed by either using the touch screen or by rotating the physical rotary knob on the
Statera 15/100 version 1.1
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Summary of Contents for Statera 15/100
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