Proportional and Integral (PI), Temperature Controller (1 Load used in
Heat-only or Cool-only Mode), with
12-Bit Digital Temperature Sensor, Two RS232
Ports, Integrated Heat-Sink
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 Networkable Boards can be interconnected
to form a 3-wire Local Area Network, LAN.
PI Temperature Control:
Proportional and Integral (PI) Temperature Controller
in the -500C to +1200C Range with 0.0650C steps
on 1 Load. Heat-only or Cool-only (but not both at the same time).
Heat or Cool Mode is selected with network command "m".
One Digital Temperature Sensor:
A Digital Temperature Sensor with 0.06250C
and 1/20C Accuracy
-100C to +800C Range, and approx.
-550C to +1250C Range.
Temperature Sampling Rate:
The temperature is sampled at approximately 1Hz rate and the
control-loop/display is updated with this same rate.
An Optional LCD Port:
For Set and Measured Temperature Display.
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.
PWM Load Control: One 60A MOSFET is used to PI control the load power (to
a Valves , TE cells, etc)
using 750 Hz Pulse-Width Modulation.
98.5% typical, at 30V and 20A
Voltage Requirement: A single DC Source Voltage (unregulated )
with any voltage value from 9V to 30V DC (for Vp) at 20A max.
Max Operating Temperature:
With the Integrated Finned Heat Sink, as shown.
Max Load Power: 600W at 30V, 20A.
Overall Dimensions: L=2.4", W=2.3",H=1.4" (61 x
58 x 36mm).
Components Type: 100% Solid State, NO
On Board: Filter Capacitors, Voltage Transient Suppression (VTS)
diodes, One Load-Current Indicator LED (Red=Hot/Cold).
is a 30V, 20A, Networkable, Proportional and Integral (PI) Temperature
Controller for 1 Load used in Heat-only or Cool-only (but not both at the same
The fundamental components of this controller are: a 12-Bit digital temperature
sensor; a single high-power transistor (FET); and a networkable microprocessor
that stores the selected control parameters in a nonvolatile memory and
controls the power flow to a single load (Valve, Thermo-Electric (TE) cells,
etc) using Pulse-Width Modulation (PWM). The temperature is measured with a
12-bit digital sensor and the process 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. A single mode
parameter “m” is used (m =”h” for heating and m=”c”
for cooling) to select heat-only or cool-only mode. Each time, the power must be
turned off and the TE cell leads must be reversed when the mode parameter “m”
is changed. 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. Control
parameter selection and PI tuning are defined in the network
section given below. The temperature is sampled at approximately 1Hz rate
and the control-loop/display is updated with the same rate.
A Typical Application of the
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). In
this application, one Peltier type Thermo-Electric (TE) cell is used (for
heating-only in the heat mode and for cooling-only in the cooling mode, as
selected by the ‘m’ command). 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
(DS18B20 with 12” leads and 3-pin connector). The
optional LCD module can be ordered from Signal using the part number of
(2x16 serial LCD with
back-light, 12” cable and with 4-pin connectors).
The connecting wires to the Load and the Power Supply must be heavy gauge copper
wire (#12 AWG or heavier) to handle the rated current level. In addition, these
heavy gauge wires act as a heat sink, preventing overheating.
Command Format and Local Area Network (LAN)
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.
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 .
on the "Buy this
Product" Button or the Blue
Links Below to Buy the Optional Accessories
Si15NePITC1-HC12B-30V-20A, it is recommended to buy one
Digital Thermometer and one or more Network Accessories .
Si24DTsens-12B , 12-bit Digital Thermometer (
-550C to +1250C Range, in 0.0650C
12" leads and 3pin Molex Connector.
2 Line by 16 Character LCD with 12" long cable and 4-pin
1m long Network Cable Assembly with 9-pin female DB9
1m long Network Cable Assembly 9-pin female DB9
connector and a “Junction-Box” with 5 Phone Jacks.
1m long Network Cable Assembly with 6P4c Phone Plug
connector and a “Junction-Box” with 5 Phone Jacks.
We usually ship in 2-3 business
All Products Are Proudly Made in the USA