Signal Consulting, LLC  Model Si15NePTC1-H12B-30V-20A

  Networkable, Proportional, 12-Bit Heating , Temperature Controller with RS232 Serial Ports, Integrated Heat-Sink, PWM B-Chip

Si15NePTC1-H12B-30V-20A Features: Two 60A MOSFETs  are used to control one load ( Valves , TE cells, etc). 12-Bit Temperature Control in the -250C to +1020C Range with 0.0650C  steps. Set-Temperature is Adjusted ASCII Commands in 0.10C Steps. Digital Thermometer with 1/20C Accuracy,  0.06250C Resolution   12-Bit Heating, Proportional Temperature Control:  Four User Selectable  Control Grids G0,..,G3: Grid G0 is used for small thermal loads and G3 is used for large loads. Each control grid uses sixteen non-uniformly spaced temperature levels with eight PWM duty-cycle values. The temperature overshoots and oscillations (“hunting”) are limited to approximately + or - 0. 50 C. The grid selection is defined by Table 1, given below. Alarm Kill Switch: A normally open switch (or an Open Collector npn Transistor) can be connected to jumper J1 (as shown below), J1 Open=Normal operation, J1 Short=Load (TE Cell) is open. RS232 LCD Port: For Set and Measured Temperature Display   Networkable RS232 Port: For Set-Temperature Input, and for Measured Temperature Output. Up to 61 Boards can be interconnected to form a 3-wire Local Area Network, LAN. With Integrated Finned Heat Sink Power Range: 9V to 30V DC at 2x16A max (or 2x480W) Overall Dimensions: L=2.4", W=2.3",H=1.4" (61 x 58 x 36mm). Components Type: 100% Solid State, NO Relays High Power-Efficiency: 98.5% typical, at 30V and 16A Optically Isolated Control Signals On Board: Filter Capacitors VTS diodes Two LED Indicators,  (Red=Hot, Green=Cold) Voltage Requirement: A single DC Source Voltage (unregulated ) with any voltage value from 9V to 30V DC (for Vp)    Si15NePTC1-H12B-30V-20A-2B1 Spec Sheet  (PDF)

 The Si15NePTC1-H12B-30V-20A is a 30V, 2 0A, microprocessor based, closed-loop, Networkable, Proportional, 12-Bit, Temperature Controller board that heats 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.  Two high-power MOSFETs are used to drive a single load (valves, TE cells, etc) in the 9V to 30V and 0A to 20A range. 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. Four user selectable proportional control grids G0,..G3 are used to control a wide range of thermal loads. Grid G0 is used for small loads (typically: 10cm x 10cm x 10cm Aluminum block), and G3 is for large thermal loads. The grid selection is defined by Table 1, given below. Each control grid consists of sixteen non-uniformly spaced temperature levels (centered at the set-temperature value) with eight PWM duty-cycle values are used to control the temperature in 0.0625⁰ C steps. 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 the LCD. A small 12-bit digital thermometer, Signal’s part number Si24DTsens-12B  (connected to port CN3 and uses 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 (typical length of 20 meters) temperature sensing. As the name (Ne, Networkable) implies, the desired set-temperature is selectable -25⁰C to +102⁰C range, with 0.1⁰ C steps; using ASCII command strings, obtained from the RS232 Network Port, CN5. The RS232 data format and the Local Area Network (LAN) commands are described on the next page. A “Kill-Switch” (connected to J1) is used for emergency TE-off (switch open=TE-Cell on, Switch closed=TE-Cell off with zero current, as shown on the application drawing below). An LCD port (with RS232 Interface Standard) is provided for display of the Set and Measured temperature data. The 2 line x 16 character LCD can be ordered from Signal under the part number of Si14LCD2L16CH  (with 12” cable and 4-pin connectors and with back-light). A Green LED is used to monitor the TE cell (or load) voltage. This board operates with a single unregulated voltage source (9V to 30V range). A small (2.4.0”x2.3”x0.4”), integrated, finned heat-sink is used to operate at 480W power level. Higher power-levels can be achieved with more efficient heat-sinks. Typical applications are: Peltier Effect TE Coolers, Heat Pumps, etc.

Grid Selection, Table 1

The DIP switches define four heating ranges centered at the Set Temperature. Heating  Pulse Width Modulation (PWM) starts when the measured temperature is within a selected range; otherwise the PWM is 100%. This table defines the amount of power is applied to the heating  element (or TE cell) as the measured temperature approaches the Set Temperature. The user can control temperature overshoots and oscillations (“hunting”) by choosing the proper Grid Number for his application.

 A Typical Application of the Si15NePTC1-C12B-30V-20A

In this 12-bit, closed-loop, proportional 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). In this application, two Peltier type Thermo-Electric (TE) cells are used (one for heating, and a second for cooling). The TE Cells can be purchased from:  www.customthermoelectric.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 optional LCD module can be ordered from Signal using the part number of Si14LCD2L16CH  (2x16 display with 12” cable and 3-pin connectors, and with back-light).A wide variety of Linear and Switching Type of Power Supplies can be purchased from: http://www.mpja.com/powersupply.asp.   

 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 Si15NePTC1-H12B-30V-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, CN6) 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, CN6) 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.

Command Rules:

1.  All Commands are ASCII character strings (Chars.).  An ASCII string is denoted here with Bold Red Letters (Characters).

2.  Each string is terminated by a Carriage Return Character, (CR). The only exception is the # command.

3.  Upper-Case Letters are used for Output Commands; and Lower-Case Letters are used for Input Commands.

4. The 1^st Char. in a string is either ASCII # or a Node Address (1, .,9,A..Z, a,..,z). If the 1^st Char. is a #, it denotes a query to all boards on the LAN to output their Node Address and Program Name.

5. If the 1^st Char. is an ASCII (1..,9, A,..Z, a,…,z), it directs the rest of the command string to the board that has this address.

6. The 2^nd Char. in the string is the Command Character that operates on the addressed board.

7. The 3^rd, 4^th, 5^th and 6^th Chars. represents the value of the input data. Where + denotes positive Set-Temperature values; and - denotes negative Set-Temperature values.

8. The last Char. in the sequence is always the string terminator, (CR).

Command Examples on Input Line I1:

Ex#1.  Com. String:  #     Action: All boards on the LAN will output their Address and Program Name.

Ex#2.  Com. String:  1u5(CR)          Action: Change Board 1 Address in EPROM from 1 to 5.

Ex#3.  Com. String:  1T(CR)           Action:  Board 1 outputs its Set and Measured Temperature.

Ex#4.  Com. String:  1Q(CR)           Action:  Board 1 outputs the Measured Temperature.

Ex#5.  Com. String:  2t25(CR)        Action: Change Board 2 Set-Temperature to +25.0C.

Ex#6. Com. String:  2t+25.0(CR)    Action: Change Board 2 Set-Temperature to +25.0C.

Ex#7.  Com. String:  2t-25(CR)       Action: Change Board 2 Set-Temperature to -25.0C.

Ex#8. Com. String:  2t-25.0(CR)     Action: Change Board 2 Set-Temperature to -25.0C.

You must use approximately 25msec (or longer) delays between characters when inputting a command string (“1t..(CR)”, “1T(CR)” or “1Q(CR)”) to this controller board. Occasionally, a transient character may be captured and buffered by one more board on the LAN, this transient character can be cleared by sending one  or more (CR) prior to a valid command string. Valid Measured Temperature values are given at 1Hz rate; consequently commands strings can be sent at 0.66Hz rate.

Response to Commands on Output Line I2:

The response to a "1T(CR)" command is an ASCII character string (or a line of characters). Each string is terminated with carriage return and line feed characters. An example is shown below: 

N=1  ST=+025.00 C  MT=+023.87 C 

Note that there are two space characters between 1 and S; and there are two space characters between C and M. The length of this character string is 33, including carriage return and line feed characters   (not shown in this example). 

Where N=1 is the node (or unit) address of the board (can be changed with the u command), ST=+025.00 C is the last Set-Temperature in degree Centigrade (entered with the t command), and MT=+023.87 C is the current Measured-Temperature in degree Centigrade. 

The response to a "1Q(CR)" command is: T1=+023.87 C   (with carriage return and line feed).

The response to a "1Q(CR)" when the sensor is not connected is: T1=No Sensor  (with carriage return and line feed).  Each character string (line) is a continuous stream of ASCII characters with an occasional pause (or delay) between characters. This delay is approximately 1msec.

The on-board microprocessor provides the bus arbitration, required to avoid data collisions on the 3-wire LAN bus.

2-Line by 16-Character LCD Display Format:

 An optional 2-Line by 16-Character serial LCD (Si14LCD2L16CH-3PC) can be connected to port CN2.

This +5V, RS232 serial LCD operate at 9600 Baud rate with: 1 Stop-bit, 8 Data-bits, 1 Stop-bit, No Parity-bit.  A typical LCD display is given below: 

Line 1:    NST=+025.00 C Px    

Line 2:    NMT=+025.00 C Gy 

Where:  N is the node address, ST=Set-Temperature, Px= PWM value in use, x=0=0%, x=1=12.5%, x=2=25.0%,… x=7=100%, MT=Measured-Temperature, Gy=Grid Number in use, (as selected with jumpers J4 and C5) y=0,1,2,3.

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 Note: Sig-Note on Configuring a LAN-2 .

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