The TC-36-25-RS232-UL has the same features as the TC-36-25 RS232, including bi-polar (heat and cool) proportional-integral-derivative control that can modulate input voltages of up to 36 V at currents of up to 25 A. This version is CE marked and is MET-Labs listed, conforming to UL 60730-1. Due to listing requirements the controller does not come with a temperature sensor (thermistor) or RS232 cable, but these can be ordered separately. Windows-compatible,  LabVIEW-based GUI software is available as a download, the LabVIEW source code is available free of charge upon request, and a sample read and write command programmed in Python is also available for download.

SKU: 3022. Category: .

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The Model TC-36-25-RS232-UL is a bi-polar (heat and cool) proportional-integral-derivative temperature controller that can modulate power input from 12 V up to 36 V, or from 0 V to 36 V with a second power supply, at currents of up to 25 A. It is essentially the same as the TC-36-25 RS232 but it has modifications that allow it be CE marked as well as MET-Labs listed, conforming to UL 60730-1. In addition, Windows-compatible software is provided for direct communication via the serial communication port. LabVIEW-based GUI available is also available as a download, the LabVIEW source code is available free of charge upon request, and a sample read and write command programmed in Python (2.7) is also available for download from the SOFTWARE tab on this web page.

NOTE: Temperature sensors (thermistors) are not included with the controller due to UL 60730-1 requirements and must be ordered separately.

The RS-232 cable (MP-3023) is also not included and must be ordered separately.

The TC-36-25-RS232-UL does not come with a thermistor or RS-232 cable; they must be ordered separately.

The TC-36-25-RS232-UL provides bi-directional temperature control for thermoelectric devices, either independently or with supplemental resistive heaters for both cooling and heating applications. The controller uses solid-state MOSFET devices in an electrical “H” bridge configuration to automatically control the direction of current simply based on the temperature set point.

The controller can be communicated with and programmed directly through a personal computer’s RS232 serial communication port. The supplied communications software,


compatible with Windows 10, 8, 7, provides a graphical user interface; no prior programming experience is required to use it. However, the command set is provided so that qualified personnel can use it is as an embedded control or can create a custom program interface using LabVIEW, for example.

An alternate LabVIEW based GUI available as a download (see downloads page), and the source code for that is available upon request. That download includes the LabVIEW Runtime Engine, so the LabVIEW application is not required to run the software.  A sample read and write command programmed in Python (2.7) is also available for download from the SOFTWARE tab on this web page.

Once the desired controller parameters are established, the settings can be saved to non-volatile memory. The TC-36-25-RS232-UL can then be disconnected from the computer and operated as a unique, stand alone controller. The controller can also be configured to use a variety of analog inputs to adjust the set point.

Mechanically, the controller’s printed circuit board is mounted to a metal bracket that is suitable for either horizontal or vertical orientation. The controller can operate in ambient temperatures from 0 C up to 60 C without generally requiring additional heat sinking.


  • Low voltage TE device control capability. The TC-36-25-RS232-UL requires an input voltage anywhere from 12 V up to 36 V. That voltage powers the microprocessor and can also be modulated and sent to the thermoelectric device. However, if the thermoelectric cooler or Peltier device operates on a voltage lower than 12 V, a second low-voltage power supply can be connected. The controller will then switch this voltage on and off to the TE device. The second input voltage can range anywhere from 0 V to 36 V.
  • High resolution and Stability. The output signal to the thermoelectric cooler is pulse-width modulated (PWM) at 2700 Hz. The PWM control scheme affords temperature resolution of 0.01 C or 0.01 F and best-case controller stability within 0.01 °C or 0.02 °F. The controller tuning structure allows designation of a variety of control features: manual, proportional, proportional-integral, proportional-derivative, or proportional-integral-derivative control. Differential temperature control is also available when two input sensing thermistors are used.
  • Accepts a wide variety of thermistors. The controller comes with a standard 15k ohm thermistor which provides a control temperature range of -20 C to 100 °C. However, the controller can be used with a wide variety of other NTC type thermistors which are pre-programmed and selected via a menu in the software. For example, a 5k ohm thermistor can also be used to extend the control temperature down to -40 °C. Also, since many laser diode packages come standard with a 10k thermistor, there are two different 10k thermistor settings available.
  • Remote control capability. Once the controller is programmed, it can run independent of a computer, and the set point can be adjusted in several ways. The optional MP-2986 Display and Keypad accessory can be used to adjust the set point and provide a digital readout of the set point and the sense temperature. The controller can also use a potentiometer, a 0 to 5 VDC signal, or a 0 to 20 mA current loop.
  • Configurable alarm actions. Several alarm types may be selected: no alarm, tracking alarm, and fixed value alarm. The alarm can be configured to either maintain the output power during an alarm or to shut down the power output. The alarm latch can be selected to either automatically restart power if the alarm clears itself or to keep the power output off until the latch is manually cleared. The controller can also provide a 25 mA signal for powering an LED or other device when an alarm occurs.
  • Over-current protection. In addition to alarm protection, the controller can provide over-current protection to the TE device. The setting can be adjusted in 2.5 A increments. The maximum current the controller can handle is 25 A at steady state.


  • CE marked, including RoHS Compliace, MET-Labs listed.  MET Labs is a Nationally Recognized Test Lab approval similar to a UL listing.
  • Bi-directional, solid-state “H”-bridge configuration for heating and cooling applications
  • Input voltage from 12 to 36 VDC or 0 to 36 VDC with a secondary power supply
  • Self-contained, 0.1 to 25 A load rating, with over-current protection
  • Computer programmable via RS232 communications port or stand-alone operation without a computer
  • Control temperature of -20 C to 100 °C, other ranges available with optional thermistors
  • Proportional (P), Integral (I) and Derivative (D) control
  • Temperature resolution and best-case control stability of 0.01 °C
  • Pulse-width modulation frequency at 2700 Hz
  • 5K, 10K, and 15K ohm thermistor capability
  • Set temperature adjustable via:
    Remote user set temperature potentiometer
    4 to 20 mA current loop
    0 V to 5 V adjustable range
    Differential temperature control
    MP-2986 Display and Keypad accessory
  • No computer programming experience required to use the communications software program
  • Command set is provided so programmers may create their own software interface or embedded controller applications (sample LabVIEW source code, version 2011 and higher, is available upon request)
  • A sample read and write command programmed in Python (2.7) is also available for download from the SOFTWARE tab on this web page.
  • Computer configurable alarms
  • Non-volatile memory retention of parameters
  • Operating temperature range of 0 C to 60 °C, storage temperature range of -55 C to 105 °C

Download TC-36-25-RS232-UL Manual

Download Temperature Sensor Attachment Manual

Standard Coolers and Temperature Controllers Catalog

Download TC-36-25 RS232 Software (See also Software License Agreement)

Download code example (simple read and write command)

TC-36-25 RS232 3D Model in .pdf format (Requires Adobe Reader 8.0 or higher)

3D PDF MODEL: Click on the link above to download a 3D model. You can rotate and view the cooler from any angle to better understand the physical properties of the product. (However, wire leads are not shown in the model.) This is a portable document format (.pdf) file, Adobe Reader 8 or higher is all that is required for viewing. 3D content may initially appear as a two-dimensional preview image. Clicking the 3D model with the Hand or Select tool enables (or activates) the model and opens the 3D toolbar.

NOTE WHEN SAVING FILES: When downloading a solid model some browsers may change the name of the extension. You must save the file to your computer using the “Save as” option and rename the extension back to the appropriate type before using. (For example, a SolidWorks file will be saved with the .htm or .html extension, the file extension must be changed back to .sldprt before using.)

Compatible with: