Sensor Input Error Messages; Sensor Curve Selection - Lakeshore 330 User Manual

Lake Shore Model 330 Autotuning Temperature Controller User's Manual
Type E (Chromel™-Constantan)
Type E is a thermocouple pair consisting of a Ni-Cr alloy (Chromel™) as the positive thermoelement and a
Cu-Ni alloy (Constantan) as the negative thermoelement. It has the highest sensitivity of the three standard
thermocouples (E, K and T) typically used for low temperature applications: 8.5 µV/K at 20K. This
thermocouple is best for temperatures down to 40 K. It is recommended for oxidizing or inert environments.
Do not use it in sulfurous or reducing atmospheres, or environments that promote corrosion. Recommended
useful temperature range is 3 K to 475 K.
Type K (Chromel™-Alumel™)
Type K is a thermocouple pair consisting of a Ni-Cr alloy (Chromel™) as the positive thermoelement and a
Cu-Al alloy (Alumel™) as the negative thermoelement. It may be used in inert environments, but not in
sulfurous or reducing atmospheres, or environments that promote corrosion. Sensitivity at 20K: 4.1 µV/K.
Recommended useful temperature range is 3 K to 575 K.
Type T (Copper-Constantan)
Type T is a thermocouple pair consisting of Cu (Copper) as the positive thermoelement and a Cu-Ni alloy
(Constantan) as the negative element. It may be used in a vacuum as well as oxidizing, reducing or inert
environments down to 90 K. At temperatures below 80 K, the thermoelectric properties of the positive
thermoelement depend largely on the impurity of iron. The high thermal conductivity of the copper element
makes this thermocouple the least usable for cryogenic applications. Sensitivity at 20 K: 4.6 µV/K.
Chromel™-CuFe (0.15%)
The Chromel™-Copper/Iron thermocouple consists of a Ni-Cr alloy (Chromel™) as the positive
thermoelement and a Copper/0.15% Iron alloy as the negative thermoelement. Sensitivity at 4.2K: >11 µV/K.
Less expensive than Gold-Chromel™ thermocouples and physically stronger. Recommended useful
temperature range is 4 K to 300 K.
2.6.3

Sensor Input Error Messages

If an input signal from the sensor exceeding full scale is applied to the input leads, an overload condition exists
and is indicated by "OL" on the display.
If no signal or a signal of the wrong polarity exists at the input leads, a Zero Error is indicated by "Er27" for
Channel A or "Er28" for Channel B.
The Model 330 displays dashes "- - - -" if the input switch is improperly set.
2.7

SENSOR CURVE SELECTION

For accurate temperature readings, select the response
curve that matches the sensor used. To determine curves
currently selected, press Curve. The Sample window
displays the curve for Sensor A, while the Control window
displays the curve for Sensor B.
This sample display indicates Sensor A is using Curve 02
and Sensor B is also using Curve 02. Curve 02 is the DT-
400 Series Curve 10. The default curve is Curve 02 for
silicon diodes, and Curve 03 for platinum RTDs and
thermocouples.
To change the curve, press and hold the Curve key and
press the s key to increment the Sensor A curve or the t
key to increment the Sensor B curve number. The curve numbers available are 00 through 31. When the
proper curve number is reached, let go. Table 2-3 lists the standard curves with curve number and
temperature range. If a curve with the wrong temperature coefficient (slope) is selected, the Model 330 selects
the default curve for the sensor type.
Installation
Sample
LOC
Control
OFF
2-7