Whether they operate on analog or digital principals, the performance and efficiency of temperature controllers are determined by their power output percentage. Simply put, the power output is the current delivered to the load and the output percentage is the power delivered relative to the maximum power of the temperature controller.
For example, if a temperature controller is transmitting 0% of a 10 Volt (V) signal, the power output will be 0V. Conversely, a 100% power output percentage would be 10V. Power output percentage can be controlled in increments across this full scale, though the sensitivity of control varies depending on the temperature controller’s capabilities.
In this blog post, Glas-Col explores why the power output percent is important for temperature controllers.
Relative Measure of Power
Firstly, power output percentage is a measure of the actual power output relative to the maximum output. This is useful for a number of reasons. It is ideal for manual analog controllers that do not have a digital display nor a proportional integral derivative (PID) controller. The power output percentage is controlled using the dial on the manual controller, which adjusts the signal voltage required to reach the indicated temperature on the dial. Typically, in manual controls, the higher the number on the dial, the higher the output percentage.
Assisting PID Control
Digital controllers with PID control are much more precise, determining the exact power output percent required to reach the setpoint and maintain temperatures within an acceptable band.
Though sensitive, digital PID controls still operate on a time cycling principal that calculates the required signal value over time to reach the setpoint. This results in thermal oscillations that can cause undesirable and even dangerous temperature overshoot. One other feature on most PID controls is the ability to manually reduce the power output percent. This is extremely important when working with very small loads to prevent overshoot but may require empirical testing and adjusting the percent to achieve the best results. Additional controls are available for minimizing overshoot with temperature controllers.
Temperature Controllers from Glas-Col
Glas-Col is one of the leading suppliers of laboratory instrumentation in the U.S. We offer a broad range of temperature controllers, thermocouples, and additional safety controls to ensure the utmost accuracy in heat-controlled experiments. If you have any questions about our temperature controllers, please do not hesitate to contact a member of the Glas-Col team.