User`s manual

48 cHAPTER 4: Operation
Model 335 Temperature Controller
4.4.1 Diode Sensor
Input Setup
Diode sensors include the silicon and the gallium aluminum arsenide sensors
detailed in TABLE 4-6. Input ranges are selectable to 0 V to 2.5 V or 0 V to10 V, and
standard excitation current is 10 µA.
As an alternative to the standard diode excitation current of 10 µA
, you may select a
1 mA excitation. The 1 mA excitation current is not calibrated, and will not work prop-
erly with standard Lake Shore diode sensors. For protection against accidentally set-
ting the 1 mA excitation current, the Diode Current
setting is automatically set to
10 µA every time the Sensor Type is set to Diode.
Menu Navigation:
Input SetupQInp
ut (A, or B) QSensor Type (Diode)
Input SetupQInp
ut (A, or B) QSensor Type (Diode)QRange (2.5 V [Silicon] or 10 V 
[GaAlAs])
Input SetupQInp
ut (A, or B) QSensor Type(Diode)Q
ENTER
Q Diode Current 
(10 µA or 1 mA)
Default: Se
nsor TypeQDiode
RangeQ2.5 V (Sil
icon)
Diode Current Q10 µA
Interface Command: INT
YPE, DIOCUR
4.4.2 Positive
Temperature
Coefficient (PTC)
Resistor Sensor Input
Setup
PTC resistor sensors include the platinum and rhodium-iron sensors detailed in 
TABLE 4-6. More detailed specificati
ons are provided in TABLE 1-2. The Model 335
supplies a 1 mA excitation current for the PTC resi
stor sensor type. A resistance range
selection is available in order to achieve better reading resolution. Autorange is
enabled by default in order to provide the best possible reading resolution, but it does
not affect the sensor current excitation. Refer to section 4.4.4 for details on manually
selecting the range. Current Reversal is also enabled by default in order to compen-
sate for thermal EMF voltages. Refer to section 4.4.5 for details on the Thermal EMF
Compensation (Current Reversal) feature.
Menu Navigation:
Input SetupQInp
ut (A, or B) QSensor Type (PTC RTD [Platinum])
Interface Command: INT
YPE
4.4.3 Negative
Temperature
Coefficient (NTC)
Resistor Sensor Input
Setup
NTC resistor sensors include Cernox™, Rox™, Thermox™, and others detailed in 
TABLE 4-6. More detailed specifications are provided in TABLE 1-2. The excitation cur-
rent for the NTC RTD sensor type can vary between 100 nA and 1 mA, depending on
resistance ran
ge. When autoranging is enabled, the range will be automatically
selected so that the excitation voltage is below 10 mV. This keeps the power dissi-
pated in the sensor at a minimum, yet stil
l enough to provide accurate measure-
ments. Current Reversal is also enabled by default in order to compensate
for thermal
EMF voltages. Refer to section 4.4.5 for details on the Thermal EMF Compensation
(Current Reversal) feature.
Menu Navigation:
Input SetupQInp
ut (A, or B) QSensor Type (NTC RTD [Cernox])
Interface Command: INT
YPE