TE Technology TC-720 - Manual (Page 55)

3. FAN CONTROL - : Select this option if the fan uses a PWM control signal where decreasing the amount of time the
fan-speed wire is shorted to ground causes an increase in fan speed. Most fan-speed control fans will use this
setting, but you will need to consult with the manufacturer to determine which setting is appropriate.
When programming or adjusting the fan control settings, always monitor and verify that the TE device and
the fan operate as intended and within the safe operating limits under all applicable operating conditions.
Fan control should only be used with fans that are specifically designed to be speed controlled using PWM.
Using PWM control on a fan not designed for it can create a hazardous condition by damaging or overheating
the controller, the fan, and the TE device.
The fans used in TE Technology’s Thermoelectric Cooling Assemblies are NOT designed to be speed controlled
using PWM unless specifically indicated as such in the product literature.
Do not use fans whose current would exceed 2.0 A, including instantaneous peak/inrush current which can
occur at the leading edge of the PWM waveform.
Reducing fan speed will reduce air flow and result in a warmer heat-sink operating temperature. This will
then reduce the heat pumping capacity of the TE device. It may also reduce the maximum allowable ambient
temperature in which the TE device can be safely operated. If the fan speed is too low, it may cause the heat-
sink temperature to exceed the maximum temperature rating of the TE device.
Most fans designed for PWM control require a 5 V signal, although some fans have built-in circuitry that may
allow for a higher voltage. In addition, you may need to add a pull-up resistor to limit current flow through
the fan circuitry. Consult with the fan manufacturer for further details.
ALARM 1 FUNCTION:
1. KEEP OUTPUT ON: if an alarm condition exists based on the control sensor temperature being above the
temperature entered in the HIGH ALARM 1 SETTING, or if the control sensor temperature is below the
temperature entered in the LOW ALARM 1 SETTING, the controller will continue to provide output power to the TE
device regardless of the alarm condition.
2. TURN OUTPUT OFF: if an alarm condition exists based on the control sensor temperature relative to the HIGH
ALARM 1 SETTING or the LOW ALARM 1 SETTING, the controller will shut off output power to the TE device.
ALARM 2 FUNCTION:
1. KEEP OUTPUT ON: if an alarm condition exists based on the secondary sensor temperature being above the
temperature entered in the HIGH ALARM 2 SETTING, or if the secondary sensor temperature is below the
temperature entered in the LOW ALARM 2 SETTING, the controller will continue to provide output power to the TE
device regardless of the alarm condition.
2. TURN OUTPUT OFF: if an alarm condition exists based on the secondary sensor temperature relative to the HIGH
ALARM 2 SETTING or the LOW ALARM 2 SETTING, the controller will shut off output power to the TE device.
ALARM 2 SENSOR:
1. INPUT 1: the Alarm 2 transistor turns on if an alarm condition exists relative to the control sensor.
2. INPUT 2: the Alarm 2 transistor turns on if an alarm condition exists relative to the secondary sensor.
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