Libratherm Instruments Private Limited

Two To Six Set Point On-off Temperature Process Controller

Libratherm offers New version HTC-966 which are designed and developed using the latest micro-controller. The specification incorporated serves the every simple and critical process control applications of the industry. It accepts input from temperature sensors like thermocouple, RTD (Pt-100), Infrared thermocouple, or pyrometers generating mV or mA signals or from the level/flow/pressure/pH transmitters in the form of (4-20) mA. The input signals from thermocouples and RTD (Pt-100) are software Linearized for 1oC/0.1oC indicating accuracy. It can also be used for other process control applications like pressure control, level control etc. accepting input signals from the respective transmitter or transducers.

HTC-723 / HTC-966 accepts universal input. User can select one of 8 different types of input using back panel DIP switch. This is the added advantage over the fixed type of input.

The controller HTC-723 and HTC-966 has respectively 2 to 4 and 2 to 6 programmable set points. Each can be configured as either High Alarm or Low Alarm or Deviation Alarm or for Off state with programmable ON/OFF hysterisis through user friendly membrane key board. Dual 4 digits display allows simultaneous indications of the process value and the set value. In addition these models can give two nos. retransmission output of 4-20mA proportional to process value, for remote indication of the process value.

Features:
• Highly accurate and sturdy in operation.
• Elegant looks, Very easy to operate.
• Accepts standard type of thermocouple or RTD (Pt-100) 2 or 3-wire input.
• Control output of Relay or DC pulse or TRAIC.
• Programmable Hysterisis.
• User configurable output up to 4 or 6 set points.
• Models available in 2, 3 and 4 configurable set points
• High quality membrane keypad.
• Operates on Universal supply of 90 to 250 VAC, 50/60 Hz.

Application:
• Pressure control
• Heater bank selection
• Star delta changeover
• Level control
• Process industry
• Plastic / Packaging industry

Model Wise Description:

Description:

Libratherm offers Microcontroller based multiple Ramp / Soak programmable PID temperature controller Model PRC-489 which is designed to improve reliability, accuracy and control for all temperature control applications. It features Ramp and Soak functions (the capability to control the temperature and its rate of change over a predetermined time span). Single pattern of total 16 (ramp/soak) steps can be programmed and stored in the memory. It can also be used as single set point control when the ramp/soak profile control is not desired. The controllers are caIibrated for K type thermocouple.

PRC-489 offers both switching outputs in the form of SSR driver/Triac (AC SSR) for external SSR or external load contactor and analog output in the form of (4-20) mA or (0-5) volt control signal, which can be used to control heater power through external Thyristor power regulator. The analog outputs can be directly connected to Libratherm make single phase / three phase SCR based phase angle or zero cross over fired power regulators.

Additional one/two relays are also provided for time or temperature dependent event outputs as per the system requirement. The programmed profile and other parameters are retained in the nonvolatile memory in the event of power failure. In case of thermocouple break, the control can be transferred to manual mode to continue the heating cycle and user can alter the % of control output. The deviation hold feature assures guaranteed ramp. For quick heating from ambient temperature the hold feature is disabled in the very 1st ramp. Front Panel LED indicates start and end of the cycle, the status of heater output, status of heating ramp, soaking or cooling ramp. The unit of temperature measurement can also be selected as oC or oF as desired.

To monitor the on line temperature profile of the heating system, RS 485 serial communication interface can be optionally provided, the same can be connected to the computer. Libratherm provides the window based software to program the controller and to view the on line behavior of the heating cycle in both graphical and tabular format. The same RS485 interface is used for Master/Slave programming as shown below.

Features:

• Accepts standard type of thermocouple, RTD, Voltage or Current signal.
• Control output of Relay / TRAIC / DC pulse / (4-20)mA/ (0-5)Volt.
• Servo start from the current process temperature.
• 1 to 16 programmable ramp/soak steps with rate programming facility.
• Master / Slave concept with 1 master and max. 30 slaves.
• Each controller can be configured as master or slave with 1 master and many slaves.
• Can be used as single set point control with online set point change facility.

Applications:

• Furnace / oven control
• PWHT and SR heat treatment cycle