Lakeshore 336, Руководство пользователя

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52 c
HAPTER
4: Operation
Model 336 Temperature Controller
4.4.1 Diode Sensor
Input Setup Diode sensors include the silicon and the gallium aluminum arsenide sensors
detailed in TABLE 4-7. Input ranges are selectable to 0–2.5 V or 0–10 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 Setup
Q
Input (A, B, C, or D)
Q
Sensor Type
Q
Diode
Input Setup
Q
Input (A, B, C or D)
Q
Diode Current
Q
(10 µA or 1 mA)
Input Setup
Q
Input (A, B, C or D)
Q
Range
Q
(2.5 V [Silicon] or 10 V [GaAlAs])
Default: Sensor Type
Q
Diode
Diode Current
Q
10 µA
Range
Q
2.5 V (Silicon)
Interface Command:
INTYPE, 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 4-7. More detailed specifications are provided in TABLE 1-2. The Model 336
supplies a 1 mA excitation current for the PTC resistor 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 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 Setup
Q
Input ( A, B, C, or D )
Q
Sensor Type
Q
PTC RTD (Platinum)
Interface Command:
INTYPE
4.4.3 Negative
Temperature
Coefficient (NTC)
Resistor Sensor Input
Setup NTC resistor sensors include Cernox™, Rox, Thermox and others detailed in TABLE 4-7.
More detailed specifications are provided in TABLE 1-2. The excitation current for the
NTC RTD sensor type can vary between 100 nA and 1 mA, depending on resistance
range. When autoranging is enabled, the range will be automatically selected so that
the excitation voltage is below 10 mV. This keeps the power dissipated in the sensor at
a minimum, yet still enough to provide accurate measurements. 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) fea-
ture.
Menu Navigation:
Input Setup
Q
Input (A, B, C, or D)
Q
Sensor Type
Q
NTC RTD (Cernox)
Interface Command:
INTYPE
4.4.4 Range Selection The Model 336 is equipped with an autoranging feature that will automatically
select the appropriate resistance range for the connected resistive temperature
device. In some cases it may be desirable to manually select the resistance range. To
manually select a resistance range, set the Autorange parameter to Off, then use the
Range parameter to select the desired range. Autorange will be On by default when-
ever the Sensor Type parameter is set to PTC RTD or NTC RTD. Autorange is not avail-
able for the Diode sensor type.