A profiler, sometimes called a profile controller or programmer, is an electronic device used in a closed loop system to read an input value from a measuring device and provide an output for the controlled variable to follow the value of the actual setpoint over time, increasing, decreasing or holding its value as required. See the diagram example below.
The controlled variable is measured by a suitable sensor and converted to a signal acceptable to the profiler. The profiler compares the measured value to a desired value (setpoint), and a profile has been created where the setpoint is programmed to rise, fall, and hold over time. The profiler alters the controlled variable using proportional or linear outputs to accurately follow the moving setpoint matching the created profile steps (segments).
Gems 3500 Series pressure transducer measures pressure in a steam autoclave used to sterilizes liquids. The 3500 Series transducer sends a 4-20 mA scaling linear signal to a PMA KS98-2 Multi-function Controller with profile functionality. The profiler converts that 4-20 signal to read 0-30 PSIG, and the setpoint is adjusted to 15.5 PSIG. The KS98-2 provides an output to an electric pressure control valve. When actuated, the modulating valve closes or opens to either increase or slowly exhaust steam pressure. The chamber pressure must decrease slowly to prevent the liquid from boiling as it would do if pressure was exhausted all at once. The KS98-2 can also control the chamber temperature at the same time heating to 121.5 °C. Liquid sterilization autoclaves require both pressure and temperature profiles to complete the process. Both controlled variables increase to their target setpoints (15.5, 121.5) at a controlled ramp rate. They are to be held stable at those values for 30 minutes. Then they are both reduced at a slow controlled rate to prevent boiling over until back to ambient temperature and atmospheric pressure completing the sterilization cycle.
See the profiles from this example below:
Profilers can include many auxiliary functions to support your application.
- Integral Power Supply
- Remote Profile Control
- Digital Inputs
- Real Time Clock
- Data Recorder
- And more...
Gems Sensors & Controls and West Control Solutions are happy to offer a wide range of profilers to help with your process control needs. See more HERE.