Libratherm offers Microcontroller based PID/On-Off Humidity and Temperature Controller Model HTC-3003 with input and output suitable for measuring and controlling the T and RH of stability or environmental test chambers or walk-in chamber. These chambers are mainly used in Pharma, Petroleum, Chemical, and Food Industries to test and store the product/sample under the desired simulated and control climatic environment.

The Calibrated Temperature and Humidity Controller HTC-3003 accepts input from the standard T + RH sensors consisting of (Pt-100) temperature sensor and the capacitive type RH sensor or from direct T + RH sensor/transmitter. (The suitable sensors or transmitters of international brands can be used along with this controller). The input signal is processed by 16 bit ADC for a very accurate and stable display. The time tested PID algorithm gives accurate control of Temperature and %Rh. The single controller has the advantage of tracking and synchronizing the two different process parameters over individual control for temperature and %RH.

In model HTC-3003, the process values and set values are displayed simultaneously on 4 independent 4 digits 7-segment Red / Green LED displays. The real-time is displayed on an extra 4 digit display.

Since these controllers are basically designed for the stability chambers, the accurate control of temperature and humidity is achieved by operating the air heater (for Dry heat) and the boiler heater (for Moisture or water vapor) in the PID control action, and the compressor (for low temperature) is operated in ON/OFF action with user-programmable time delay facility. Since the compressors are not required to be kept ON above a certain level of temperature, the user-selectable mode is provided to program the compressor operation in AUTO, Continuous ON, or Continuous OFF mode. To de-humidify the system, an extra ON/OFF output is provided to operate either the same compressor or an extra compressor – with a time delay function. All the control outputs are in the form of SSR drivers of (0 to 12) VDC pulse to control the Air heater, boiler heater, and compressor, and dehumidifier. In case of water level low, the audible alarm is generated and heaters are turned off to prevent dry run and safety.

HTC-3003 has many other useful features:
1. In-built real-time data storage facility, which can be retrieved on-demand or can be downloaded on to a computer or on a printer for a hard copy via the built-in serial printer port. The storage capacity depends on the logging time. Maximum 3600 records can be stored which can be printed in Offline mode. The battery-backed non-volatile flash memory is used for data storage.

2. HTC-3003 accepts 2 nos. of external potential-free contacts (DI) to detect the water level of the boiler used for generating the steam or moisture and to monitor the status of the front door of the chamber – through limit switch contacts.

3. HTC-3003 optionally offers serial communication port RS-485 over MODBUS RTU protocol for interfacing to the computer for data logging and storage purpose. Specially designed window-based E-Chamber Software allows users to monitor and program the controller through laptop or PC.

Key Features:

• Microcontroller based design.
• Easy front panel keyboard programmable.
• Independent 4 control outputs for Temperature/%RH control (4 x DO).
• Digital input for water level, door switch, etc (2 x DI).
• User programmable alarm limits with auto snooze facility.
• PID or ON/OFF control action for Air heater, Boiler heater and ON/OFF control action for Compressor with programmable time delay.
• Direct dot matrix serial output for EPSON printer model LX-300+ or Equivalent.
• RS-485 port for computer interface.
• User friendly and expandable Window based PC software.