Stanford Research Systems LDC500, Руководство по эксплуатации и обслуживанию

Страница: 35 / 141

2.2 Operating the TEC controller 2 – 7
no model (raw resistance units). If you have Steinhart-Hart
coe
ffi
cients for the sensor, select [1]; otherwise select the more-
common
β
-model by pressing [0], followed by [Enter].
•
Press [ ] to enter the sensor model coe
ffi
cients, pressing [Enter]
and then [ ] after each value. Stop when you reach the “Au-
totune” menu selection. The default coe
ffi
cients correspond to
commonly-used 10 k
Ω
NTC sensors.
Assuming you have correctly connected and configured your sensor,
and placed the TEC controller in CT mode, you should now see the
sensor temperature (generally around room temperature) displayed
on the large green numeric display labeled “Thermoelectric Cooler.”
For more information about sensor types, models and parameters,
see section 4.5.13.
2.2.2 TEC settings
After having configured the sensor, the operating settings for the TEC
controller needs to be entered. These settings include the operating
temperature, upper and lower temperature limits, the TEC voltage
limit, and the TEC current limit.
Begin by pressing the [Set] button to navigate to the TEC Settings
menu tree.
•
Press the [ ] button repeatedly to reach the top of the menu tree.
•
Enter the desired operating temperature setpoint (in degrees
Celsius), say 25.005, using the numeric keypad or the wheel.
Press the [Enter] button to accept the value.
•
Press [ ], and enter the maximum TEC module current (in am-
peres), followed by [Enter].
•
Press [ ], and enter the upper temperature limit ( T
max
, in de-
grees Celsius), and press [Enter].
•
Press [ ], and enter the lower temperature limit ( T
min
, in degrees
Celsius), and press [Enter]. Unless your laser assembly is in
a dry-purged environment, be sure to set this value above the
dew point to avoid undesired condensation on your laser.
•
Press [ ], and enter the maximum operating voltage for your
TEC module, followed by [Enter].
After the TEC controller is properly configured for your module
and sensor, you still need to set the control-loop parameters (
P , I ,
and D ). The LDC500 provides a PID autotune function which can
automatically optimize the loop parameters.
LDC500 Series Laser Diode Controllers