ILX Lightwave LDC-3700C Series, User Manual, Page: 51 / 176

O P E R A T I O N S
Operating the TE Controller from the Front Panel
04_09 LDC-3700C Series
35
C H A P T E R
2

Operating the Controller in Resistance (Sensor) Mode, R
Selecting R in the TEC mode section of the front panel selects constant resistance
mode. In this mode, the temperature controller will maintain temperature so that
the temperature sensor’s resistance, current, or voltage remain constant,
depending on whether the sensor is a thermistor, AD590, or LM355. This mode is
useful if the sensor constants are not known or the sensor values are only known
at the operating temperature. When using this operating mode, the control
setpoint must be in terms of the sensor output units, namely k

, µA, or mV.
Operating the Controller in Constant Current Mode, I
TE
Selecting I
TE
in the TEC mode section of the front panel selects constant TE
current mode. In this mode, the temperature controller will output a constant
current when the output is enabled, regardless of temperature. The output will
only be disabled by manually turning the output off or if the temperature hits the
high temperature limit. This mode is useful if a fixed thermal load requires heating
or cooling and absolute thermal control is not required. Setting a positive current
value is defined to produce cooling of the load while a negative value defines
heating of the load.
Automatic Shut Off Conditions for TEC Output
The following conditions will automatically cause the instrument to disable the
TEC output:
• High Temperature Limit
• Connecting pins 13 and 15 on the TEC connector (external/booster temperature limit
switch)
• Booster Changed (while Output is enabled), (see Chapter 5)
• Sensor Open (while Output is enabled)
• TEC Module Open (while Output is enabled)
• SENSOR SELECT Switch Moved (while Output is enabled)
• Sensor Shorted (while Output is enabled)
• TEC mode changed (while output is enabled)