Newport LDC-3706 Series, User Manual

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December 2019 101 LDC-3706 Series Laser Controller
ITE Current Calibration
The following procedure calibrates the I
TE
constant current source for both polarities of current.
During this procedure the I
TE
current is driven to two pre-determined values. When each of
these values is reached and is stable, the user enters the actual value of the current, as
measured by an external DMM. The LDC-3706 Laser Controller then automatically calibrates
the TEC current source and limits.
1. Measure and record the exact resistance of a 2 Ω , 150 W resistor. A 4-point probe
resistance measurement is recommended.
2. With the output off, connect the 2 Ω , 150 W resistor across the TEC output terminals.
Pins 1, 2 (TEC+) and 3, 4 (TEC-) on the 15-pin connector for the LDC-3726 or pins 9,
10, 21, 22 (TEC+) and 12, 13, 24, 25 (TEC-) for the LDC-3736/LDC-37620.
3. Navigate to the “I
TE
Cal” selection in the Calibration submenu of TEC parameter menu
tree.
4. Select the I
TE
calibration mode by pressing the SET button while the “I
TE
Cal” selection is
displayed. Then, press the TEC button to start the calibration procedure. Calculate the
actual current output by using Ohm's Law:
=
Where V is the accurately measured voltage across the resistor with a precision
multimeter and R is the accurately measured load resistance. The first current should be
approximately 1 or 2 A (positive).
5. Turn the ADJUST knob until the display shows the value of the I
TE
measurement as
calculated from step 4. Then press the TEC button.
6. The instrument will apply a second current (approximately negative 1 or 2 A) after a
short time. Repeat step 5 for the newly calculated current at this setpoint.
7. Wait for the 7-segment display to exit the calibration mode. Once the self-calibration is
completed, the calibration constants will be stored to the non-volatile memory and the
display will return to its previous state.
TEC Voltage Measurement Calibration
The following procedure calibrates the TEC voltage measurement.
1. Calibrate the I
TE
current as described in the section above.
2. With the output off, connect a 2 Ω , 150 W resistor across the TEC output terminals. Pins
1, 2 (TEC+) and 3, 4 (TEC-) on the 15-pin connector for the LDC-3726 or pins 9, 10, 21,
22 (TEC+) and 12, 13, 24, 25 (TEC-) for the LDC-3736/LDC-37620.
3. Connect a calibrated DMM across the load resistor. Navigate to the “V
TE
Cal” selection in
the Calibration submenu of TEC parameter menu tree.
4. Enter the calibration mode by pressing the SET button while the “V
TE
Cal” selection is
shown on the display. Then, press the TEC button to start the calibration process.
5. Measure the voltage using the DMM. Adjust the voltage shown on the lower display to
match the measured voltage by turning the ADJUST knob. Then press the TEC button.
6. The instrument will apply a second current after a short time. Repeat step 6 for the new
voltage measurement.
7. Wait for the 7-segment display to exit the calibration mode. Once the self-calibration is
completed and calibration mode is exited, the calibration constants will be stored to the
non-volatile memory and the display will return to its previous state.