Signal Consulting, LLC 

Model Si25NeTEPITC1-12B3S-50V-20A 

Networkable, Thermo-Electric (TE), Proportional and Integral (PI), 12-Bit, Temperature Controller (1Load, Heat and Cool) with an RS232 Serial Control Port, Integrated Heat-Sink, Three 12-Bit Digital Sensors (2 Auxiliary), and with a Serial LCD Ports, 750Hz PWM





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Si25NeTEPITC1-12B3S-50V-20A Features:

Networkable 9600-Baud RS232 Input/Output Control Port: For Set-Temperature and control parameter Input; and for Measured Temperature and Control parameter Output . All control parameters are stored in nonvolatile memory. Up to 61 Boards can be interconnected to form a 3-wire Local Area Network, LAN.

PI Temperature Control: 12-Bit Proportional and Integral (PI) Temperature Controller in the -500C to +1200C Range with 0.0650C  steps on 1 Load.

Efficient H-Bridge with PWM: 750Hz Pulse-Width Modulation (PWM) is used to perform the heating and cooling function (at the same time) on a Peltier type (TE) cell, functioning as a bidirectional heat-pump.

One Digital Temperature Control Sensor (DTS1): A 12-Bit Digital Temperature with 0.06250C Resolution and 1/20C Accuracy  in the -100C to +800C  Range, and approx.  1.00C Accuracy in the -550C to +1250C  Range.

Two Auxiliary sensors (DTS2, DTS3):   The two 12-Bit Digital auxiliary sensors (same as DTS1) reports the temperature readings at any remote locations in the -550C to +1250C range with 0.06250C precision and 1.00C accuracy.

Temperature Sampling Rate:  The temperature is sampled at approximately 1Hz rate and the control-loop/display is updated with this same rate.

An RS232 LCD Port: For Set and Measured Temperature Display.

Alarm Kill Switch on J1: A normally open switch (or an Open Collector npn Transistor) can be connected to jumper port J1 (as shown below), J1 Open=Normal operation, J1 Short=Load (TE Cell) is open.

Voltage Requirement: VC (from pin +C to pin - P): 9V to 30V DC, and for VP (from pin +P to pin -P) 9V to 50V, both unregulated DC voltages. For low-voltage applications (9V to 30V) a single DC power supply can be used by connecting pin +P and pin +C together.

High Power-Efficiency: 98.5% typical, at 50V and 20A

Max Load Power: 1000W at 50V, 20A.

Max Operating Temperature: +450C with the Integrated AP1 Aluminum Plate Heat Sink Heat Sink, as shown.
Power Semiconductors: Four 90A Hex-MOSFETs
Overall Dimensions: 4.0" x 3.3" x 1.4" (102 x 84 x 34mm).
Components Type: 100% Solid State, NO Relays

On Board:
Optically Isolated Control Signals
Filter Capacitors, Voltage Transient Suppression (VTS) diodes.
Bicolor LED Indicator,  (Red=Hot, Green=Cold) 



 For Details, Download the  Si25NeTEPITC1-12B3S-50V-20A-5B2   Manual


The Si25NeTEPITC1-12B3S-50V-20A is a 50V 20A, Networkable, Thermo-Electric (TE), Proportional and Integral (PI) Temperature Controller that perform the heating and cooling function (at the same time) using 1 Peltier type (TE) cell, functioning as a bidirectional heat-pump. The fundamental components of this controller are: three 12-Bit Digital Temperature Sensors; sensor DTS1 in the control loop and two Auxiliary sensors (DTS2, DTS3); an efficient high-power H-bridge that controls the TE cell current (in the 0 to +/- 20A range) using 750Hz Pulse-Width Modulation (PWM); and a networkable microprocessor that controls the temperature, stores the selected network parameters in a nonvolatile memory and drives the H-bridge. The two Auxiliary sensors (DTS2, DTS3), these can report temperature readings at any remote locations in the -550C to +1250C range with 0.06250C precision and approximately 1.00C accuracy. The temperature of the enclosed thermal-zone (measured with DTS1) is (PI) controlled with 0.06250C steps in the -500C to +1200C range. By PI control, we mean that the amount of correction used in the control-loop is proportional to the difference and the Integral of the difference between the set and measured temperature values. A single DC power supply (in the 9V to 30V and 0A to 20A range) is required to operate this controller. Two proportional-band parameters are used “c”= 001,...199 for Cold band, and “h”= 001,...199 for Heat band. One step change in the band parameter represents a 1 degree C change. Two control bands are used because the TE cells are more efficient in heating mode than in the cooling mode. These proportional control bands are centered at the set-temperature value; and a smaller band value represent more aggressive proportional control. Full heating or cooling TE-cell power (100% PWM) is used when the measured temperature is outside of this selected band; and reduced TE-cell power (100% to 0% PWM as specified by the PI control) is used inside this band. The integral gain “i”= 001,...199 controls the contribution of the integrator to the total PI control sum. Larger integral gain values represent higher integral contribution (“i”=199 represents 100% contribution). The integrator is reset to zero each time a new set temperature is selected and its growth is limited to prevent excessive integral contribution ( “integral windup”). A wide range of thermal loads can be efficiently controlled with proper control parameter selection. The temperature overshoots and oscillations (“hunting”) are limited to approximately + or - 0. 50C.

A Typical Application of the Si25NeTEPITC1-12B3S-50V-20A

In this 12-bit, closed-loop, (PI) temperature control application, the Set-Temperature is adjusted  by command strings derived from a Personal Computer (PC) using the Microsoft “Hyper Terminal” program (or any-other ASCII controller) operating at 9600 Baud, 1 start-bit, 8 data-bits, 1 stop-bit, No parity-bit. The Peltier type Thermo-Electric (TE) cell is functioning as a bidirectional heat-pump. The TE cells can be purchased from: A simple unregulated DC power supply is shown below, wide variety of linear and switching power supplies can also be used with this board; click on to find these supplies. The temperature of the enclosed 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 optional LCD module can be ordered from Signal using the part number of Si14LCD2L16CH-4PC  (2x16 display with 12” cable and 4-pin connectors, and with back-light).  Warning:  The connecting wires to the Load and the Power Supply must be heavy gage copper wire (#12 AWG or heavier) to handle the rated current level. In addition, these heavy gage wires act as a heat sink, protecting the board from overheating.

Command Format and Local Area Network (LAN) for the Si25NePITC1-12B3S-50V-20A

Each board has a unique, 8-bit, ASCII, none-volatile, Node-Address ranging from 1….9, A..Z, a,…z; (or a total of 61 Units can be networked). The address can be changed by a LAN command (the factory default address is 1). The board uses a modified version of the RS232 serial-data communication standard, where the output-voltage (on pin I2, CN5) ranges from 0 to +5V (rather than the usual -12V to +12V). In addition, this output pin is normally an open circuit; and it will only output a serial TTL binary bit-stream when properly referenced by its Node-Address. The serial data input-voltage (on pin I1, CN5) has the standard range of -12V to +12V. The serial data-format is: 9600 Baud Rate, 1 Start-Bit, 8 Data-Bits, 1 Stop-Bit, and no Parity-Bit. These features allow the creation of a Local Area Network (LAN) with up to 61 nodes (boards). A typical 3-wire LAN with “Star Topology” is shown below. Note that the control lines (G, I1, I2) with the same name are connected together (or the boards are connected in parallel) and driven by an ASCII controller (or PC), equipped with an RS232 serial port, operating at 9600 Baud rate.

Network Configuration: The on-board microprocessor provides the bus arbitration, required to avoid data collisions on the 3-wire LAN bus. The  Si..Ne.. boards can be arranged in many Local Area Network (LAN)  topologies: Star, Daisy-Chain, etc. You may create your own network or you may order one or more of the Network Cable Assemblies  listed below. Before you build your network, click on this blue link and read this Application NoteSig-Note on Configuring a LAN-2 .

 Click on this Blue Link to  Download the  Si25NeTEPITC1-12B3S-50V-20A-5B2   Manual


  Click on the "Buy this Product" Button  or the  Blue Links  to BUY these Accessories

Si25NeTEPITC1-12B3S-50V-20A,  Networkable Thermo-Electric Proportional and Integral (PI) Temperature Controller 50V, @ 20A.
Price $269.00

Note: If Buying the Si25NeTEPITC1-12B3S-50V-20A, it is recommended to buy one Si24DTsens-12B Digital Thermometer and one or more Network Accessories .

Si24DTsens-12B , 12-bit Digital Thermometer ( -550C to +1250C Range, in 0.0650C Steps) with 12" leads and 3pin Molex Connector. 
Price $39.00
Optional Si14LCD2L16CH-4PC  2 Line by 16 Character LCD with 12" long cable and 4-pin connectors.  
Price $59.00
Si25-DB9cable1 , 1m long Network Cable Assembly with 9-pin female DB9  connector.
Price $19.00
Si25-PJtoHcable-1m , 1m long cable assembly with Phone Jack and Header connector.
Price $19.00
Si25-LANhub5  , 1m long Network Cable Assembly 9-pin female DB9  connector and a “Junction-Box” with 5 Phone Jacks.
Price $39.00
Si25-LANext5  , 1m long Network Cable Assembly with 6P4c Phone Plug  connector and a “Junction-Box” with 5 Phone Jacks.
Price $29.00

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