TC-36-25-RS485

The TC-36-25-RS485 comes with one MP-3193 thermistor. If you would like to purchase additional thermistors, they can be ordered separately from the thermistors page.

OVERVIEW
The TC-36-25-RS485 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 RS485 and programmed directly through a personal computer when used with an optional RS485 adapter. This method of communication allows multiple controllers to be assigned individual addresses, daisy-chained together, and communicated with using only one port on your computer. The supplied communications software,

compatible with Windows 10, 8, 7,  provides a graphical user interface; no prior programming experience is required to use it. The software was developed using LabVIEW, but LabVIEW is not required to run it. However, the command set is provided so that qualified personnel can use it is as an embedded control or create a custom program interface. The LabVIEW source code is available free of charge 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.

Once the desired controller parameters are established, the settings can be saved to non-volatile memory. The TC-36-25 RS485 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.

TECHNICAL DESCRIPTION

• Low voltage TE device control capability. The TC-36-25 RS485 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 a 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-derivate, 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.

SPECIFICATIONS

• RoHS Compliant
• 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 RS485 communications or via an optional USB-to-RS485 converter 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 (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