LDTC-LAB datasheet(5/31 Pages) WAVELENGTH

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ADJUST TEMPERATURE

SETPOINT

1. Press to access the TC Control Screen.

2. Press the blue Setpoint temperature value

and turn the adjustment knob to change it. The

instrument will beep when set.

The TC Control Screen is also the location of the PID

control parameters and IntelliTune (intelligent autotune)

characterization scan. The PID values are manually editable

or can be adjusted automatically via IntelliTune.

ENABLE TC CURRENT

Press the

TC ENABLE button on the front panel. There is no

delay before the button illuminates and the current flows to

the thermoelectric.

When current to the thermoelectric is enabled, this light will be

illuminated blue.

Using a 10 kΩ test load, temperature will not stabilize. Current

will drive to the positive limit if setpoint temperature is below

25ºC and to the negative limit if setpoint is above 25ºC.

SET THE LIMITS – LD

1. Press to access the Laser Diode Driver

Control Screen.

2. Access the LD Limit Screen, press the blue

text to make it editable, then use the adjustment

knob to configure the limits as required.

If current reaches the set limit, output current will

remain at the limit. Output will not be disabled if

the limit is reached.

CHOOSE LD CONTROL MODE

On the LD Control Screen, choose either

Constant Current or Constant Power mode.

Pressing the text toggles the selection.

It is not editable while LD current is enabled.

CONSTANT CURRENT MODE

Constant Current (CC) mode maintains a constant current

through the laser. The setpoint corresponds to the current

through the laser.

CONSTANT POWER MODE

Constant Power (CP) mode maintains a constant current

through the monitor photodiode, corresponding to a constant

power output. If CP mode is chosen, additional parameters

must be set on the Photodiode Screen. The test load will not

work in CP mode.

1. Press to access the Photodiode Screen.

2. Press the blue text next to "PD Biasing" to

toggle whether the bias voltage for the photodiode is

enabled or disabled. See the Photodiode Basics App

Note for more detail.

3. Press the blue text next to "PD Range" until the value

matches the appropriate current range for the photodiode.

The available options are 500 μA, 5 mA, and 10 mA.

4. If the transfer function relating photodiode current to

optical power is known, this value can be entered using

the "Transfer Function" setting. Units are W/mA.

SET LASER TYPE

Access the LD Control Screen. Edit the laser

type by pressing the blue text to toggle between

Types A/B and Type C lasers.

Type A Laser Diode

Type B Laser Diode

Type C Laser Diode

Common

Cathode

Laser Diode Anode &

Photodiode Cathode Common

Isolated Photodiode

Short the

Laser Diode Anode

to Photodiode Cathode

Common

Anode

Laser Diode Cathode &

Photodiode Anode Common

Figure 4. Laser Type Diagrams

NOTE: Type A/B lasers use a separate connection on the rear

panel from Type C lasers. Ensure that the proper rear panel

connection is made in addition to selecting the proper type on

the LD Control Screen.

SET LASER SETPOINT

Also from the LD Control Screen, edit the laser current setpoint

by pressing the blue text and turning the adjustment knob.

Note: For added safety, if the setpoint is set to the value of

the current limit, actual current will be ~43 mA below setpoint.

ENABLE LASER CURRENT

Press the

LDD ENABLE button on the front panel. By

default, there is a 2 second delay (user-adjustable via remote

commands) between the time the button is pushed and current

being supplied to the load.

When laser current is enabled, this light will be illuminated

solid red.

MONITOR ALL I/V OUTPUTS

Press to access the Dual Monitor Screen.

From here, both the TC and LD output

parameters are displayed. Parameters are not

editable from this screen.

SHUTDOWN THE INSTRUMENT

If either of the Enable buttons are illuminated, current is still

flowing to the load. Before shutting down, the current needs

to be turned off.

1. Press the Enable button. The button light will turn off and

current to the test load will stop.

2. On the back panel, press the power switch to the

position. The instrument will shut down.

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