Libratherm offers various models of Digital and Microprocessor based Temperature and Humidity Indicator / controller. The model HTC-3000 and HTC-3003 are specially designed for Environmental test chambers, however, they can be used for any HVAC applications, where simultaneous and accurate control of desired temperature and humidity is required.
The controller accepts input signal from direct RH sensor for humidity control and / or RTD (Pt-100) sensor for temperature control. The controller gives three dc pulse outputs for controlling Air heater for dry heat, Boiler heater for humidity and Compressor for low temperature control. The 4th output is also optionally available for dehumidification. The control action is PID or On/Off for heaters and On/Off with built in programmable time delay for compressor. The compressor can be operated in Auto, On or Off mode as per control temperature requirement - above ambient, below ambient or below zero.
Each channel loop parameters like PID, Set and hysterisis can be programmed from the front keyboard. The additional facility of built in real time clock, RS-485 or RS-232 PC interface, data storage and printer output for 80-column dot matrix printer (CENTRONIX output - suitable for EPSON model LX-300+ or equivalent ) is also provided for analysis of temperature and humidity behaviour date and time wise.
The Controller has the built in non-volatile memory for the retention of the programmed values in case of power failure and on resumption of power the control will resume from the last value. To suit the control system, the special interlocking of the compressors and heaters are incorporated to enhance the performance and safety of the entire control system, which is achieved by switching off the compressor, if the air heater temperature exceeds certain preset value.
The model DTH-100 is a digital temperature/humidity indicator. The single and two set point on/off control outputs in the form of relay contacts are also available for simple control applications.

Libratherm offers various models of Digital and Microprocessor based Temperature and Humidity Indicator / controller. The model HTC-3000 and HTC-3003 are specially designed for Environmental test chambers, however, they can be used for any HVAC applications, where simultaneous and accurate control of desired temperature and humidity is required.
The controller accepts input signal from direct RH sensor for humidity control and / or RTD (Pt-100) sensor for temperature control. The controller gives three dc pulse outputs for controlling Air heater for dry heat, Boiler heater for humidity and Compressor for low temperature control. The 4th output is also optionally available for dehumidification. The control action is PID or On/Off for heaters and On/Off with built in programmable time delay for compressor. The compressor can be operated in Auto, On or Off mode as per control temperature requirement - above ambient, below ambient or below zero.
Each channel loop parameters like PID, Set and hysterisis can be programmed from the front keyboard. The additional facility of built in real time clock, RS-485 or RS-232 PC interface, data storage and printer output for 80-column dot matrix printer (CENTRONIX output - suitable for EPSON model LX-300+ or equivalent ) is also provided for analysis of temperature and humidity behaviour date and time wise.
The Controller has the built in non-volatile memory for the retention of the programmed values in case of power failure and on resumption of power the control will resume from the last value. To suit the control system, the special interlocking of the compressors and heaters are incorporated to enhance the performance and safety of the entire control system, which is achieved by switching off the compressor, if the air heater temperature exceeds certain preset value.
The model DTH-100 is a digital temperature/humidity indicator. The single and two set point on/off control outputs in the form of relay contacts are also available for simple control applications.