Wavelength Electronics LDTC0520, Datasheet And Operating Manual

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LDTC0520 / LDTC1020 LASER DIODE AND TEMPERATURE CONTROLLER
WIRE THE LDTC FOR YOUR
TEMPERATURE CONTROL APPLICATION
Remove the test loads, and reconfigure the temperature
controller with your temperature sensor and load. Refer
to Table 3 to find the proper wiring diagram for your
configuration.
If the sensor is not a 10 kΩ thermistor then you must make
internal modifications to the LDTC; refer to page 17 .
For operation of a TEC using a thermistor, Figure 11
illustrates the wiring required.
LDC
PDA
Spare
LDA
COM
TEC+
TEC-
SEN+
SEN-
COM
J3
See Note
Thermistor
1
10
-
+
Note: Current flows from TEC+ to TEC-.
Connect the TEC+ lead to pin J3-6 and
the TEC- lead to pin J3-7. Keep the wires
as short as possible to reduce lead voltage
drop at high current.
Figure 11. NTC sensor and TEC Wiring
CONFIGURE ONBOARD OR EXTERNAL
SETPOINT CONTROL
The temperature setpoint can be controlled with an onboard
trimpot, or by external signal input to pin J2‑11.
Select the temperature setpoint reference by setting the
TREF switch; refer to Figure 12 . To use the onboard trimpot
for temperature setpoint control, set the TREF switch to
INT (down). To reference the EXT T SET input, set the TREF
switch to EXT (up).
J1
J2
J3
Figure 12. Configuration DIP Switches
ADJUST THE TEMPERATURE SETPOINT
If the LDTC is configured for onboard temperature control,
the setpoint is adjusted using the T SET trimpot, accessible
through the hole in the cover. The temperature setpoint
corresponds directly to the desired voltage drop across the
temperature sensor.
If the LDTC is configured for external setpoint control,
connect the signal source to pin J2‑11. Example setpoint
circuits are shown on page 19 , and the transfer function
for the EXT T SET input is shown in Table 2 .
With either onboard or external control, if the temperature
setpoint signal falls below 0.3 V, the failsafe circuit in the
controller will be activated. This resets the temperature
setpoint to 1 V, corresponding to 25ºC when using a 10 kΩ
thermistor. To reset the failsafe circuit, the setpoint voltage
must be set to > 0.4 V. The default safety temperature can be
changed at the factory; contact Sales for more information.
MONITOR SENSOR VOLTAGE AND SETPOINT
VOLTAGE
Connector J2 includes outputs for monitoring actual
temperature sensor voltage and temperature setpoint
voltage. The specifications for the pins are indicated on
page 4 , and the transfer functions listed in Table 2 on
page 5 .