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CALIBRATION
Environmental Conditions
10 TCM-39032
CHAPTER 3
Environmental Conditions
Calibrate this instrument under laboratory conditions. ILX recommends calibration
at 23
o
C + 1.0
o
C. When necessary, however, the LDC-3900 Modular Laser Diode
Controller may be calibrated at its intended use temperature if this is within the
specified operating temperature range of 0 to 50
o
C.
Warm Up
The LDC-3900 should be allowed to warm up for at least 1 hour before calibration.
TEC Calibration Procedures
There are only three calibration procedures required for the TCM-39032, when
using thermistors.
• Calibration of the resistance at the 10 microamp source current setting
• Calibration of the resistance at the 100 microamp source current setting
• Calibration of the ITE current limits
If linear temperature sensors are used, they should be calibrated as outlined in
the following sections. If the user has the optional Model 1231 GPIB/IEEE-488.2
interface, remote calibration procedures are also listed.
Local Operation Thermistor Calibration
The following procedure is for calibrating the 100 µA and 10 µA constant current
sources so that the thermistor resistances for these ranges will be as accurate as
possible. This procedure is for local (front panel) operation.
1 Set the SENSOR SELECT switch (back panel) to the THERM position and set the
THERM RANGE switch to the 100 µA position. Select the TCM-39032 for calibration by
pressing the appropriate (ADJUST) LAS / TEC switch (so that the TEC indicator is
orange).
2 Measure and record the exact resistance of the metal film resistors. (A 4-point probe
resistance measurement is recommended.)
3 Connect the correct metal film resistor to the thermistor input of the TCM-39032 (pins 7
and 8). Use nominal values of 10 KΩ for the 100 µA setting and 100 KΩ for the 10 µA
setting.
4 Enter the TEC sensor calibration mode by pushing the (GPIB) LOCAL and (TEC
DISPLAY) R switches at the same time. The TEC display will become blank for 2
seconds, then the sensor code (SENSOR SELECT switch position) value will be
displayed for 2 seconds. After this, the TEC display will indicate sensor resistance in KΩ.
The LDC-3900 will beep when it is ready to accept a new calibration value.