Lightwave Communications LDT-5525 manual Booster Operation

O P E R A T I O N

General Operating Procedures

C H A P T E R 2

an external current booster. A switch or control circuit of the user's own design is required. It is left as an option which the user may or may not employ.

Booster Operation

The LDT-5525 Temperature Controller may be used to control a booster current source which accepts a control signal of up to +5.0 volts. A booster current source may be required if the LDT-5525 Temperature Controller's +4 A, 24 W output is not adequate to control a thermal load.

Whenever a connection is present between the BOOSTER PRESENT (pin 14) and DIGITAL GROUND (pin 15) of the back panel TEC connector (Figure 2.3) the TEC OUTPUT will be disabled. In this case, the BOOST CONTROL signal voltage will be available for controlling a booster current source.

The booster current source should use the control voltage which is available between the BOOST CONTROL (pin 10) and AGND (pin 9) of the back panel TEC connector.

During Booster operation, the normal ITE output is disabled, and the ITE display will measure about 0.0 Amps (+0.05 Amps). The CONTROL SIGNAL voltage is linearly proportional to the control current (1 V/A), which is limited by the LIM I parameter. If LIM I is set to 4 Amps, the maximum CONTROL SIGNAL voltage will be approximately 4 volts. If a booster signal greater than +4.0 volts is required, a user-supplied control signal amplifier is required. For example, if the user's control signal amplifier has a gain of 2, an I LIMIT of 3 Amps would allow a control voltage of +6 volts.

Whether or not a booster current source is used, the LDT-5525 Temperature Controller uses a sensor for controlling the temperature.

The feedback loop GAIN may require adjustment when a booster current source is used. This is because a booster current source may be used with different thermal loads than those found with normal LDT-5525 Temperature Controller operation, and those loads may require larger or smaller GAIN values in order to settle to the set temperatures in a desirable fashion.

Contact ILX Lightwave for more information on using the LDT-5525 with a booster current source.

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