TE Technology TC-24-12 - Manual (Page 6)

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The TC-24-12 also allows the use of thermostatic control devices to be used in place of over-
temperature thermistors. These devices essentially are electrical contacts that are either
electrically open or closed. When a thermostatic device is used in place of the thermistor, an
over-temperature fault is signaled when the contacts of the thermostat electrically close (that is,
use a thermostat that is normally open and closes on temperature rise). If the jumper on JP4 is
out then the power is restored when the contacts open. This allows the user to select thermostats
that close and open at temperatures that are different from the pre-programmed 50 °C and 70 °C
thermistor temperatures.
NOTE: If you are using an over-temperature thermostat in place of a thermistor, make sure that
both wire leads from the thermostat are electrically isolated from all other points in the system.
This can be accomplished by simply purchasing a thermostat with electrically isolated leads or
by ordering the thermistors with an optional plastic sheath.
5.0 Test Points
One ground test-point and four signal test-points are provided to aid in setup and for monitoring
the sensor voltage and the potentiometer voltages. Test points allow the user to read the Set
Temperature, P, I, and thermistor voltages. See “Component Identification” and “Controller
Wiring Diagram” for additional reference.
6.0 Temperature status LEDs
Three LEDs are provided to indicate the status of the temperature of the control sensor relative to
the set temperature. If the control sensor is more than 1 °C colder than the set temperature the
blue LED is illuminated, if it is within 1 °C of set temperature the green led is illuminated, and if
it is more than 1 °C warmer than set temperature the red is illuminated.
7.0 Fault Detection Indications
All LEDs will flash simultaneously at approximately if fault sensors are used and a fault
condition is detected. The LEDs will illuminate sequentially (red, green, blue, etc.) when the
control sensor is detected as open or short circuit.
8.0 Fuse
The TC-24-12 uses one 15-amp automotive-type fuse. Should the fuse blow open, the cause of
failure should be remedied, and the fuse should be replaced with Littlefuse part number 257015
or equivalent.
9.0 Alarm Output Connector
The input and output connections are made through the connector JP2, (TYCO/AMP part
number 640452-4). This is a 4-pin male header; there are a number of possible female mating
connectors, but an example for an insulation displacement type is TYCO/AMP 640441-4.
Pins 1 and 2 of the connector are used as a voltage source and are connected to the controller’s
input voltage (JP3-1). Pins 3 and 4 are the open drain of a field-effect transistor. The drain is
closed, effectively shorting pins 2 and 3 to ground, when a control sensor or over-temperature