What is three-position control of instruments?
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When selecting a single or dual-channel digital display, there are three options under the \"Control Function\" category: measurement display, three-position control, and four-limit control or four-limit alarm output. The other two options are easy to understand, but what exactly does \"three-position control\" mean? I would be very grateful if you could provide a detailed answer. Thank you!
"Three-position control” generally refers to the use of three fixed states in a control system to regulate the operation of a device; these three states are usually: fully open, fully closed, and unchanged. In practical applications, the instrument automatically switches between these three states in response to changes in the input signal, in order to achieve control purposes. For example, in a temperature control system, the heater can be set to operate at full capacity below a certain temperature, turn off completely once another temperature is reached, and remain in its current state between those two temperatures, thereby keeping the system temperature within a stable range. .
Three-position control, also known as three-state control, is a control method that utilizes three different states for regulation during the control process. Specifically, these three states are usually: forward action (also known as “heating” or “increasing”): the system increases the control variable, such as raising the temperature, pressure, or flow rate. Reverse action (also called “cooling” or “reduction”): The system reduces the control parameter, such as lowering temperature, pressure, or flow rate. Intermediate state: The system remains inactive, with no heating or cooling taking place; in other words, it maintains its current state.
Control with a dead zone switch is a typical three-position control.
Thank you all for your answers! Then why choose “three-digit control” for single-display dual-channel digital displays?
Forward motion, reverse motion, and intermediate position