50
c
HAPTER
3:
Installation
Model 350 Temperature Controller
D
Run different inputs and outputs in their own shielded cable
D
Use twisted wire inside the cooling system
D
Use similar technique for heater leads
D
Use a grounded receptacle for the instrument power cord
D
Consider ground strapping the instrument chassis to other
instruments or computers
3.5.7 Sensor Polarity
This section describes the diode/resistor sensor inputs.
Lake Shore sensors are shipped with instructions that indicate which sensor leads are
which. It is important to follow these instructions for plus and minus leads (polarity)
as well as voltage and current when applicable. Two-lead resistors can operate with
any lead arrangement and the sensor instructions may not specify. Four-lead resis-
tors can be more dependent on lead arrangement. Follow any specified lead assign-
ment for four-lead resistors. Mixing leads could give a reading that appears correct
but is not the most accurate.
DT-670-SD Diode sensor leads
Cathode
Anode
3.5.8 Capacitance
Sensor Inputs
(Model 3061)
This section provides information for a Model 350 configured with the capacitance
sensor input option card. Capacitance inputs are not installed on the standard Model
350, but it can be added by purchasing the Model 3061 capacitance input option.
Refer to section 7.4 for installation of the Model 3061.
The Model 3061 adds a capacitance input to the Model 350, appearing on the display
as input D. The card has separate voltage feedback and current excitation for the sen-
sor. The Model 3061 is intended to control temperature in strong magnetic fields
using a Lake Shore Model CS-501 capacitance temperature sensor. The standard
inputs remain in the instrument and are fully functional.
Upon changing control to the capacitive sensor, the PID values will need to be optimized.
The Model 350 does not support temperature conversion for the capacitance input.
The temperature response of capacitance sensors shifts with thermal cycling, making
calibration unpredictable. All Model 3061 option measurement and control must be
done in sensor units. With this option, two sensors should be installed at the control
point. Use a resistive sensor in one of the standard inputs to establish a control tem-
perature and stabilize the system in a low magnetic field. Before increasing the field
strength, shift control to the capacitance sensor to maintain the current
temperature.
FIGURE 3-6
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Страница 4: ...Model 350 Temperature Controller ...
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Страница 28: ...14 cHAPTER 1 Introduction Model 350 Temperature Controller ...
Страница 53: ...Examples of PID control 2 13 4 ManualOutput 39 www lakeshore com FIGURE 2 4 ...
Страница 58: ...44 cHAPTER 2 Cooling System Design and Temperature Control Model 350 Temperature Controller ...
Страница 118: ...104 cHAPTER 5 Advanced Operation Model 350 Temperature Controller ...
Страница 178: ...164 cHAPTER 7 Options and Accessories Model 350 Temperature Controller ...
Страница 192: ...178 cHAPTER 8 Service Model 350 Temperature Controller ...