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12-Bit, Digital Thermo-Electric Proportional Temperature Controller with LCD port, and with PWM-Y
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Si24DiTEPTC1-12B-50V-20A, Spec Sheet (PDF) |
The Si24DiTEPTC1-12B-50V-20A is a versatile, fully-programmed microprocessor based, closed-loop, Digital, Thermo-Electric, Proportional Temperature Controller board that heats or cools a thermal-zone. The temperature is measured with a 12-bit digital sensor and proportionally controlled with 0.06250C steps in the -250C to +1020C range. An efficient high-power H-bridge controls the current (in the 0 to +/- 20A range) to Peltier type Thermo-Electric (TE) cells, functioning as a bidirectional heat-pump. By proportional control, we mean that the amount of correction used in the closed-loop is proportional to the difference between the set and measured temperature values. Sixteen non-uniformly spaced temperature levels (centered around a set-temperature value) with eight PWM duty-cycle values are used to control the temperature in 0.06250 C steps, (G8 Control Grid). The temperature overshoots and oscillations (“hunting”) are limited to approximately + or - 0. 50C. The temperature is sampled at approximately 1Hz rate and the control-loop/display is updated with the same rate. An onboard microprocessor measures and controls the temperature, monitors the user inputs and drives a 2 line x 20 character LCD. A small 12-bit digital thermometer, Signal’s part number Si24DTsens-12B (connected to port CN4A4 and using the Dallas Semi., DS18B20 sensor,) is used to measure and control the temperature in the -250C to +1020C range, with ½0 C accuracy. Because this sensor is digital, it is virtually immune to noise and loading; ideally suited for remote sensing. This sensor uses a unique “1-wire interface” (with parasite power mode) that requires only 2-conductors for reliable remote (long as 20 meters) temperature sensing. As the name digital (Di) implies the desired set-temperature is adjusted with the Si24PB2-MC3 Up and Down push-buttons in 0.06250 C steps. An LCD port (with HITACHI HD44780 Interface Standard) is provided for display of the Set and Measured temperature data. The 2 line x 20 character LCD can be order Signal under the part number of Si24LCD2L20CH (2x20 display with 8” ribbon cable and 14-pin connector) or can purchased from many vendors. A bicolor LED is used to monitor the TE cell (or load) voltage (Red = Heat, Green = Cold); and an optional fast acting 20A Mini-Fuse (with socket) is used for board protection. This board operates with a single unregulated voltage source (9V to 50V range). A small Aluminum plate (3.3”x4.0”x0.065”) is required to operate at 1000W power level. Higher power-levels can be achieved with more efficient heat-sinks. Typical applications are: Peltier Effect TE Coolers, Heat Pumps, etc. This board can be configured and programmed to perform efficiently in many customized applications.
A Typical Application of the Si24DiTEPTC1-12B-50V-20A
In this 12-bit, closed-loop, proportional temperature control application, the Set-Temperature (in the, -250C to +1020C Range with 0.06250C steps) is adjusted with the Si24PB2-MC3 UP and Down push-buttons, connected to port CN4DC. The Peltier type Thermo-Electric (TE) cell is functioning as a bidirectional heat-pump; operating with 12VDC (unregulated) at 20A max. TE cells can be purchased from Melcor Corp. Trenton, NJ 08648 USA, WEB: www.melcor.com. The temperature of the enclosed and insolated Hot/Cold Environment is measured with the Dallas Semi. DS18B20 (in TO-92 casing) Digital Thermometer, Si24DTsens-Spec1-DS18B20.This sensor can be purchased from Signal Consulting, LLC as Si24DTsens-12B (DS18B20 with 12” leads and connector). The LCD module can be ordered from Signal with the part number of Si24LCD2L20CH (2x20 display with 8” ribbon cable and 14-pin connectors) or can be purchased from several vendors; for OEM pricing, contact: Sunlike Display Tech Corp. in Taiwan, www.lcd-modules.com.tw .
An inexpensive unregulated DC power supply design is shown in this application drawing. This power supply consist of a transformer with a center-tap (CT) secondary winding, a 25A bridge rectifier (purchased from www.digikey.com with part number MB256-ND) and a 2200uF, 50V capacitor ( www.digikey.com part number P5187-ND). The secondary voltage and current rating of the transformer determines the DC voltage and current output of this power supply. The transformers can be purchased from www.mpja.com with the fallowing part numbers: for 33V, 10A DC output use transformer 7846-TR, for 16V, 4A DC output use transformer 7840-TR. This power supply can built under $20.
Wide variety liner and switching power suppliers can also be used with this board. Consult the most resent catalog on www.mpja.com to purchase these power supplies.

| Si24DiTEPTC1-12B-50V-20A, 12-Bit Digital Thermo-Electric Proportional Temperature Controller. |
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Note: If Buying the Si24DiTEPTC1-50V-20A, it is recommended to buy one Si600APHS1 Heat Sink., one Si24DTsens-12B Digital Thermometer, one Si24LC2L20CH 2 Line by 20 Character LCD with 8" long ribbon cable and 14-pin connectors, and one Si24PB2-MC3 Up and Down Push-Buttons with 12" lead and connector. |
| Si600APHS1 Heat Sink (3.3"x4.0"x.065" Alum. Plate) with .375" Standoffs and 4-40 screws. |
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| Si24DTsens-12B 12-bit Digital Thermometer ( -400C to +1400C Range, in 0.0650C Steps) with 12" leads and 3pin Molex Connector. |
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| Si24LC2L20CH 2 Line by 20 Character LCD with 8" long ribbon cable and 14-pin connectors. |
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| Si24PB2-MC3 Two Push-Buttons with 12" lead and with a 3-pin FM Molex Connector. |
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Typical Domestic
Shipping Cost: $12.00.
Typical
International Shipping Cost: $24.00.
Availability: We usually ship in 2-3 business days.
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All Products Are Proudly Made in the USA
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