SRS Labs CTC100, User Manual

Page: 71 / 177

Operation 59
CTC100 Programmable Temperature Controller
S ensor
Channel .Sensor { Diode, ROX, RTD, Therm }
Touch this button to select a sensor class. Four options are available: diode, ROX (ruthenium
oxide), RTD, and thermistor.
This setting controls how the sensor input hardware reads the input signal. It determines the
excitation current, whether the CTC100 reads the sensor voltage or resistance, and the list of
calibration options available in the Cal column. The Diode option sets the sensor excitation current
to 10 µA and causes the hardware to read the voltage across the sensor. The ROX, Thermistor, or
RTD option causes the hardware to read the sensor resistance. The ROX and thermistor modes are
identical, except for the list of calibration options. The RTD mode results in a larger sensor
excitation current (and therefore lower noise) and places an RTD-specific list of calibration options
in the Cal column.
Ra ng e
Channel .Range { 10ê, 30ê, 100ê, 300ê, 1kê, 3kê, 10kê, 30kê, 100kê, 300kê,
2.5V, Auto }
Sets the sensor measurement range. The default range is Auto. In general, a lower range
produces a larger excitation current, less noise, and more accurate measurements. The range
should be manually set if it is critical to limit sensor self-heating; otherwise the CTC100 may
change the range and excitation current at unexpected times.
The Auto range function increases the range by one step whenever the sensor resistance rises
above 95% of the current range, and decreases the range by two steps whenever the sensor
resistance falls below 10% of the current range.
The CTC100 uses ASCII character 234 for the Ohms symbol. To type this character on a
Windows computer, hold down the alt key and type 0234 on the number pad. On Windows
U nits
Channel .Units?
This button shows the nati
her sensor type is selected. The units cannot be changed directly, but
they change automatically if the sensor type is changed.
P lot
Channel .Plot { 1, 2, 3, 4, 5, 6, 7, 8 }
the plot type is
Choose one of eight plots for the channel to appear in, where plot 1 is the uppermost plot. Empty
; for example, if all the selected channels have been assigned
to plot 4, only one plot appears on the Custom plot screen.
L og g in g
Channel .Logging { Off, "0.1 s", "0.3 s", "1 s", "3 s", "10 s", "30 s", "1
min", "3 min", "10 min", "30 min", "1 hr", Default }
By default, readings from all channels are saved to the log at the global log rate, which is set on
the System Setup screen (
System.Log.Interval
). However, exceptions can be made for
individual channels by setting a different rate with the Logging button. To return the channel to the
F ig ures
Channel.Figures { 0, 1, 2, 3, 4, 5, 6, Default }
Sets the maximum number of digits that are shown after the decimal point for all channel values.
Fewer digits may be shown i into the available space. This setting
does not affect logged data, PID feedback, or plots.