5R7-001 & 5R7-002
Model 5R7-001
Model 5R7-002

start at quantity 2


Summary Overview
Detailed Specifications
Technical Discussion
Implementation Notes & Software
Customization for OEM Applications
Power: 900W max. 0-36vDC. 0.1-25A
Temperature Resolution: 0.01°C
Temperature Range: -40°C to 250°C depending on sensor
Control Type: Bipolar Proportional or On/Off
Communications: RS232 and command set
Setup: Comes with PC/Windows based Setup Software

Output is DC Voltage Compatible with Thermoelectric Modules (Peltier) Proportional, Integral and Derivative (PID) Controller ON/OFF Control Option Works with a Thermistor Sensor PC Compatible


The Model 5R7-001 or Model 5R7-002 temperature controller provides automatic biphase heating and cooling control for Thermoelectric (Peltier effect, or TEC) modules. (We also have a similar thermocouple based controller.)

If the cooling or heating function is switched off using the Setup program, these controllers are compatible with  resistive heaters, fans, and many other DC voltage devices that proportionately alter operation based on the amount of power supplied. Adding a diode to the output allows the controller to power a Thermoelectric module in conjunction with a resistive heater (for additional heating power), or other DC driven device. Peltier modules use only the proportional control, but On/Off control can be used instead of proportional for solenoids, relay, heaters, etc.

The user friendly Setup program requires no prior programming experience to establish operation. A command set is provided for qualified personnel to program a software interface or use as an embedded control. The software, its C++ code, and command set documentation are on the accompanying CD. For examples of using this type of command set see our library page, Communications Protocol.

Optional 5C6-576 DisplayA display is available as a PCB and cable (shown right). The Model 5R6-576 front panel display allows you to see the actual temperature or set the Set Point using 0.1 degrees resolution.

The "H" bridge configuration of the solid state MOSFET output devices allows for the bi-directional flow of current through the thermoelectric modules. Highly efficient N-channel output devices are used for this control mode.

A Pulse Width Modulated controller, or PWM controller, is a type of switched-mode controller. Our PWM controllers use square waves of varying widths and at a high frequency to provide power to the "load" (heater/cooler). Low power dissipation and precision control of the load make this type of temperature controller perferrable to analog controllers.

With peltier modules it is necessary to have a smooth transition between heat and cool modes, especially when controlling the temperature of laser diodes or telecom components. Our controllers provide a smooth transition from one mode to the other.

Compensation can be made for the difference in the efficiency of a peltier module's heat and cool modes.

Once the desired set parameters are established, the PC may be disconnected and the controller becomes a unique, stand alone controller. All parameter settings are retained in non-volatile memory.

Mechanically, the controller's printed circuit board is mounted to a metal bracket that is suitable for either horizontal or vertical orientation. Input and output connections are accessible via eurostyle screw type terminal strips, fast-on terminals, and a 0.100 center connector. ( Mechanical Drawing & Hookup)

RS232 CommunicationsThe Model 5R7-001 is PC programmable via an  "RS232 communications interface". One RS232 COM port on your computer will configure and monitor one controller. The easily accessible communications link permits a variety of operational mode configurations. (Other types of communications, such as I2C communications, can be added to a customized version of the controller. This controller is also available as the Model 5R7-002 with RS485 communications.)

The Model 5R7-002 is PC programmable via an RS485 communication port for direct interface with a compatible PC (or interface to the PC with our "RS485/RS232 converter"). The "RS485 communications interface" has 1500 VAC isolation from all other electronic circuitry minimizing interference from noise or errant signals caused by common ground loops. The easily accessible communications link permits a variety of operational mode configurations. Field selectable parameters or data acquisition in a half duplex mode can be performed.This controller will accept at least 32 addressable devices, over a maximum of 4,000 feet of communications cable.

Each controller has two sensor inputs. The second sensor input can be used for a sensor or optionally be used for remote set point adjustment using ma or a voltage or a potentiometer based dial.

All sensors are thermistors and all of our thermistors are Fenwall Curve 16, but we can customize for other R-T curves (Resistance vs Temperature). For a list of the various sensors used with this controller, and their corresponding temperature ranges, see the summary of the features in the next section.

Load | Temperature |  Controller | Mechanical | Compliance | Software | Options & Accessories
Load Type
Proportional control mode can be used for a peltier module (Compatible with Thermoelectric Modules (Peltier), TE module, Thermoelectirc module), or resistive heater (such as a thin film resistive heater, kapton heater, nichrome wire, etc.). On/Off mode can be used for a suitable relay, solenoid, heater, or fan, etc. You can also control both a peltier module and heater at the same time for additional heating power by adding a diode to the output.
Load Power Limits
Output is DC Voltage 900 Watts Max: 0-36v DC at 0.1 to 25 Amperes. If 15A or more, it is recommended you add a heatsink to the mounting bracket as the bracket acts as a heatsink for the solid state power relays. You can order the controller with a heatsink by adding "H2" or "H3" to the end of the part number (see heat sink options here).
Load Power Type
Capable of handling PWM or On/Off control. For proportional control, the controller's output is a Pulse Width Modulated (PWM) DC voltage. The voltage remains the same but the pulse width is varied. This modulates the amount of overall power provided to the load. This works with peltier modules and resistive heaters. If you are using On/Off control there is no PWM, and this is suitable for relays and solenoids, etc.
Temperature Range
-40°C to 250°C. Actual range depends on the sensor.
Range Works with a Thermistor Sensor  Thermistor
-40°C to 70°C TR141 Series 5000
-40°C to 150°C TR91 Series 10000
-20°C to 100°C TR67 or TR136 Series 15000
0°C to 150°C TR104 Series 50000
25°C to 250°C TR165 Series 231438
Temperature Units °C OR °F. Celsius or Fahrenheit.
0.01°using the Setup program or custom software. (Optional front panel display has 0.1° displayability)
Temperature Calibration Single-point calibration is possible using a temperature offset for the sensed temperature. The offset value also helps adjust for temperature gradients of the thermal system.
Internal Temperature Resolution 0.01°C. The controller measures the sensed temperature changes in increments of 0.01°C. For every change of 0.01°C the controller determines if the output power level should be changed.
End Point Temperature Stability
Not a specification. See Implementation notes below.
Power Input for Load
Output is DC Voltage Single or split power source depending voltage required for the load.
Using Single Power Source
12 to 36v DC. This powers the controller logic and is also passed through to the load.
Using Split Power Source
0 to 36v DC. The power used for controller logic must be the same voltage or higher, and a mimum of 12v.
Power Input for Controller Logic 12 to 36v DC. Less than 300ma at 12v for controller logic.
Power Input Indicator
Green LED blinks to indicate that the controller has power. ( Photo)
Power Output
Output is DC Voltage 0 to 36v DC, 0 to 25A. Split power source required for under 12v. If 15A or more, it is recommended you add a heatsink to the mounting bracket as the bracket acts as a heatsink for the solid state power relays. Ask about ordering the controller with a heatsink. Voltages can be different for the load and the logic, see Power Input and Power Input for Controller Logic above.
Power Output Resolution
0.2%. There are over 500 power levels for cooling and over 500 power levels for heating.
Power Output Polarity
Bipolar or unipolar. Bipolar means that the controller automatically switches between heating and cooling modes as required by the thermal system. Unipolar, aka single-phase, aka unidirectional, will only heat or only cool. (Bipolar is also known as biphase or bidirectional. Unipolar is also known as single-phase or unidirectional).
Power Output Bipolar Tuning
Heat side multiplier and cool side multiplier. Peltier modules tend be more efficient at heating than at cooling. The multipliers allow you to reduce the amount of power being supplied to heat, or to cool, and help to balance out the heating and cooling capability of the peltier module.
Power Output PWM Frequency
Power Output Circuit Solid State H-Bridge that handles 0.1A to 25A at DC voltages ranging from 0v to 36v.
Control Type
Proportional control, or On/Off control, or User control. Proportional, Integral and Derivative (PID) Controller Use Proportional control for peltier modules (TEC). Proportional control uses a Proportional Bandwidth (P), Integral Gain (I), and Derivative Gain (D), and it can be tuned for P, PI, PD, or PID. ON/OFF Control Option On/Off control includes an adjustable deadband (hysteresis). Additionally, User control is available if used as a variac, in which case you set the output power level to a fixed value.
Control: Proportional Bandwidth
0.10°C to 50.00°C with the Set Point being in the middle of the band.
Control: Integral Gain
0.00 to 10.00 repeats per minute.
Control: Derivative Gain
0.00 to 10.00 cycles per minute.
Control: Deadband (Hysteresis)
1.00° to 50.00° with the Set Point being in the middle of the band.
Sensor and External Adjustment Inputs
2 sensors; or 1 sensor and an external set point adjust. Input1 is for the control and alarm sensor. Input2 can be used to monitor a second sensor, or use a 2nd sensor for Differential Control. Input 2 can instead be used to set the set point using and externally supplied 0-20ma, or 0-5v, or a potentiometer.
RS-232 or RS-485 depending on the model of the controller. The Model 5R7-001 uses RS-232. The Model 5R7-002 uses RS-485. Requires cable. Transmit, Receive and Shield/Ground wires are connected to the controller using the screw down edge connector.
  • RS-232: "RS232"- can be connected directly to a COMM port of a PC.
  • RS-485: via our controller's isolated  "RS485" communications port.
  • OEM Note: Custom built controllers can use RS-485, RS-232, I2C, USB, etc.
Non-volatile memory on board for operating parameters allows for stand-alone operation. You can configure the controller using your PC and the Setup program and then disconnect the controller from your PC. If you configure the controller with EEPROM write enabled, you settings are stored in the controller and on power up the controller will use those settings.
Set Point Adjustment
Adjustment via Software or Hardware.
  • Adjust Set Point Using Software 
    • Fixed - Set fixed value from the PC.
    • Differential - Use 2nd thermistor to implement differential temperature control.
  • Adjust Set Point Using Hardware 
    • Display - Use the optional front panel display.
    • Resistance - Set remotely using a potentiometer.
    • Current - Use a 4 to 20ma current loop (max:0-20ma).
    • Voltage - Use a 1 to 5v adjustable range (max: 0-5v).
Expansion Connector For external alarm cancel switch & 3 LED indicators - Standard configuration allows an external alarm cancel switch, and provides up to 25mA for 3 LEDs as an external indication of the Low/No/High alarm states. OEM Note: With appropriate additional circuitry you could use them to trigger relays for fans or other circuits, or to light LED's to indicate power on/off, etc. For an NRE we can customize the behavior of this connector. We can also reprogram it to allow I2C communications.
Alarm Types
Sensor Open and Overcurrent Alarms, and these 4 PC configurable alarms:
  • No Alarms.
  • Set Tracking Alarms - Alarm High and Low values are relative to the Set Point temperature.
  • Fixed Value Alarms - Alarm High and Low values are fixed values.
  • Computer Controlled - Computer can trigger an alarm state.
Alarm Limits
PC configurable High and Low alarms, and an alarm deadband.
Alarm Latching
PC configurable alarm latching. Alarm state can automatically reset when the control temperature is between the High and Low alarm settings, or you can configure the controller so that the alarm state must be cleared manually.
Alarm Can Disable Output Power
PC configurable to disable output power in an alarm state, or leave outpower on.
Alarm Sensor
Input1 or Input2 as alarm sensor. PC configurable for alarms state to be triggered by either of the the two sensors (each controller is capable of supporting two sensors).
Alarm Status - External
External alarm indication and alarm cancel can be added via expansion connector. Connector supplies 5 Volts DC at 25 MA for High/No/Low alarm states. This allows you to drive LED lights to indicate the sate of the alarms visually.
Alarm Status - Software
Computer software can read the alarm state, and clear a latched alarm.
  1. Status: No Alarm.
  2. Status: High Temperature Alarm.
  3. Status: Low Temperature Alarm.
  4. Status: Computer Triggered Alarm.
  5. Status: Overcurrent Detected at Power Output.
  6. Status: Open Sensor Circuit at Input1.
  7. Status: Open Sensor Circuit at Input2.
  8. Status: Driver Low Input Voltage.
Alarm for Overcurrent at Output
PC settable overcurrent alarm. With the Setup program you can set a value that indicates that the load is drawing too much power. It is settable in increments of about 2.5A. If you set the controller to turn off the output power when the current level is passed, then you can also set the number of times the controller should restart the output before maintaining an alarm state.
Ambient Operating Temperature
-20°C to 70°C. Notes on Ambient Operating Temperature
Inches: 6" long x 3.63" wide x 1.75" high.
Centimieters: 15.35 cm long x 9.23 cm wide x 4.45 cm high.
OEM Note: We can custom build to your form factor, or take the design to SMT.
Power Connectors 0.25" Quick Disconnect Terminals are on the controller board for power input and power output.
Sensor Connectors
Edge Connector (see below).
Remote Set Point Adust Connector
Edge Connector (see below).
External Alarm Connector
Expansion Connector (see below).
Edge Connectors
Euro-style detachable header with screw-down terminal for bare wires. These are used for connecting Input1 (the control sensor), Input2 (2nd sensor or remote set point adjustment). and comunications (3 wire). ( Photo)
Expansion Connector
Molex P/N 22-23-2081 is on the controller. It has 8 pins. ( Photo)
RoHS Compliant
Compliant with the Restriction of Hazardous Substances Directive (Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment).
Setup Program
PC Compatible A PC/Windows based console program for configuring the controller comes with the controller.
Source Code
The C source code for the Setup program is provided on the software media that accompanies the controller.
Custom Software
Command set is provided so programmers may create their own software interface for embedded controller applications. The controller's command set is provided on the software media that accompanies the controller. For more infomation, see our Library page about the Communications Protocol. Free 3rd party device drivers (ActiveX Automation Servers) for the controllers are available at Kajei.com.
Heat Sink
Add H3 (short; 0.637"; ~1.62cm) or H2 (tall; 1.025"; ~2.6cm) to the end of the model number to order. It is recommended that you have a heat sink if your load requires 15A or more. The bracket is usually replaced by the heat sink. The heat sink is extruded aluminum with mounting flanges and has black anodizing. See the Implementation Notes below for more specific information.
Front Panel Display
A Model 5R6-576 front panel display is available as a PCB and cable (shown left). The display allows you to see the actual temperature or set the Set Point using 0.1° readability/settability.


We can custom build to your form factor! Low voltage, low current, small footprint versions of this controller can be custom built based on your application.

Input Supply Voltage

The Model 5R7-001 or 5R7-002 is capable of operating from an input supply voltage of 12 through 36 VDC, common to many available thermoelectric modules. However, by supplying load power separately from the controller power, you can use loads, such as thermoelectric modules, that are anywhere from 0 to 36 vdc. The self-contained MOSFET output devices deliver load currents up 25 amperes. At 15A and higher it is recommended that you add a heaetsink to the mounting bracket. You can order the controller with a heatsink by adding "H2" or "H3" to the end of the part number (see heat sink options here).

These units will control total load power up to 900 watts.

These controllers will control with a finite temperature resolution of 0.01°C.

OEM Note: To drive down the cost of production units we can custom build for fixed, or selectable, voltages and levels of power, such as fixed 5 VDC at 2 Amperes.

Output Signal

The output signal to the thermoelectric module is Pulse Width Modulated (PWM) at 2700 Hz. Pulse Width Modulation averages the amount of energy provided to the module and reduces the extreme temperature excursions that are experienced with an "on / off" type of control system. This tends to extend the life and reliability of the thermoelectric devices.


The controller tuning structure allows designation of a variety of control features. Proportional bandwidth (P) in degrees, Integral reset (I) in repeats per minute, and the Derivative rate (D) in minutes may be configured for P, PI, PD, or PID control. In addition, a deadband control (on/off) with an adjustable hysteresis may be selected. Differential temperature control is possible when two input sensing thermistors are used. The controller can also be used as a variac in whcih a computer set value provides for manual control of the output, either polarity, from 0% to 100% of load power.

Set Temperature Input

The temperature can be set directly through our standard Setup program or other software.

Additional external set temperature input types may be selected. They include a remote set temperature potentiometer, a 0 to 5v VDC (or 1 to 5v) signal, and a 0 to 20 ma (or 4 to 20 ma) current loop. These secondary inputs are used to define and "map" the secondary input to an adjustable temperature range. Differential set temperature control may also be selected from this configuration menu. All temperatures may be consistently displayed in °C. or °F.

Differential Temperature Control: Differential control is available and is accomplished by selecting the primary set temperature with the second thermistor input and establishing the offset with the computer set temperature. In other words, when using differential control you no longer set the temperature itself from the computer, but rather the offset from the temperature sensed by the second sensor. For example, A +10 degrees offset means the control temperature will always be held at 10 degrees above the temperature being sensed at the second sensor. The control temperature will be the "differential" between Input 2 (the temperature at the second sensor, which becomes a reference temperature) and Input 1 (actual system temperature).

Control Output Modes

Two types of control output modes may be selected for the controllers. This determines the direction of the current flow through the thermoelectric module during the heat cycle. This current flow may be from Wire Point WP1 (+) to Wire Point WP2 (-). Alternatively, this current flow may be reversed from WP2 (+) to WP1 (-) as selected in the configuration menu.

Variac Mode

From the PC you can choose to bypass the controllers internal control algorithms and set the output power to a specific value. There are 511 negative, 0, and 511 positive power values.


Several alarm types may be selected. The alarms provide a 5 VDC output at the expansion connector, rated for 25 ma of current. The alarms consist of a "no alarm" function, tracking alarm, and fixed value alarm. Alarm set temperature values are entered in the setup menu. The computer-controlled selection is available for additional embedded controller input/output options. The alarm setup menu also provides for selection of an alarm latching condition. The alarm sensor may be either the control temperature sensor or a secondary thermistor sensor.

Power may be maintained during an alarm condition or the output power may be shut down.  

(Notes & Software)

Photo, Mechanical Drawing, and Hookup

Temperature Stability

Temperature stability is a function of the resolution of the input temperature signal.  The controller can hold temperature to the finest increment of the input temperature signal.  The controller can resolve temperature changes down to 0.01°C. The stability you achieve depends more on the design of the overall thermal system than on the controller's resolution. These controllers provide DC voltage control with the possibility of stabilizing to better than ±0.02°C in a very well built thermal system.

OEM Note: If you start with the standard controller that has 0.01°C resolution and determine you need a controller with greater resolution for your product, we can design and provide a controller that meets the requirements of your product.


Operating Temperature of the Solid State Relays (SSR, MOSFET)

The relays are mounted to the base of the angle bracket and the bracket acts as a heatsink.

In general it is recommended that the bracket have a heatsink if your system draws 15A or more. Add "HS" to the part number to include a mounted heatsink.

Specific recommendation: The ultimate goal is to cool the Mosfet junction temperature. Measure temperature at the tab of each MOSFET under normal operating conditions. The maximum operating junction temperature is 175°C.  We recommend maintaining tab temperatures at less than 100°C if possible in order to extend the life of the product.


A PC/Windows based console program for configuring the controller comes with the unit, but you can go beyond the program provided and control the temperature controller by means of your own or other software:

Telecom, Fiber Optic & Laser Diode Notes

Customization for OEM Applications

Custom Temperature Ranges
Custom or Programmable Voltage/Current
Custom dimensions
Any Additional Circuitry / Electronics on the Same Board
Safety Features / Cutoffs / Fuses / Current Limitting
Fan Control

Custom Alarms
Uniphase Output
Various Types of Sensors
Rack Mount Versions
and more (inquire)


Note: Prices shown are for the controllers only.  Sensors, TE modules and power supplies may be available but are not included in the controller pricing.

Lead Time: The 5R7-001 is generally in stock and can be shipped in 2 to 4 days ARO. The 5R7-002 requires at least 2 weeks lead time. Out of stock items may have a 1 to 4 week lead time.

Click here for TR141 Series Sensor Housings and Prices (5K@25°C, -40°C to 70°C)
Click here for TR91 Series Sensor Housings and Prices (10K@25°C, -40°C to 150°C)
Click here for TR67 and TR136 Series Sensor Housings and Prices (15K@25°C, -20°C to 100°C)
Click here for TR104 Series Sensor Housings and Prices (50K@25°C, 0°C to 150°C)
Click here for TR165 Series Sensor Housings and Prices (231.5K@25°C, 25°C to 250°C)


MODEL 5R7-001 (RS232 Communications)
MODEL 5R7-002 (RS485 Communications)
  Quantity 01 price: $391.00 each
   Lower prices are available at higher volume starting at quantity 2.

MODEL 5R7-001 with Heatsink (RS232 Communications)
MODEL 5R7-002 with Heatsink (RS485 Communications)
See heat sink options here.
   5R7-001H3 or 5R7-002H3 Quantity 01 price: $406.00 each (controller with short heatsink)
   5R7-001H2 or 5R7-002H2 Quantity 01 price: $416.00 each (controller with tall heatsink)
  Lower prices are available at higher volume starting at quantity 2.

MODEL 5R6-576 Display
  Quantity 01 price: $119.00 each
  Lower prices are available at higher volume.


DC Load Temperature Controllers for TEC, peltier modules, fans, or resistive heaters, etc. Proportional & On/Off control.

Descriptive Indexes and Searches

SKU  Volts(v)  Amperes(A)  °C
5C7-195 1-28v 10A -40-150°

5R7-001 0-36v 25A -50-300°
5R7-002 0-36v 25A -50-300°

5R7-388 0-36v 25A -200-400°

5C7-582 9-36v 28A+ -50-300°

5R7-570 3-28v 12.5A -20-150°

5R7-350 0-24v 7.5A -20-100°
5R7-347 0-24v 7.5A 0-120°