Use of Pressure Controller

Pressure controller is a special instrument for pressure control in industrial process measurement and control system. It is usually called pressure switch in engineering. According to the working principle, it can be divided into the following two categories.

According to the working principle, it can be divided into the following two categories:

1. Mechanical pressure controller;
2. Electronic pressure controller.

Working principle:

When the pressure in the system is higher than a certain set pressure timing, the free end of different pressure sensing elements (spring tube, diaphragm, diaphragm box, bellows, piston, etc.) generates displacement, and drives the disc in the switch to move instantaneously through the link guide rod.

When the pressure drops to the rated recovery value, the disc moves in reverse instantaneously, the switch resets automatically, and finally outputs an electrical signal of the switching quantity.

Terms and definitions:

Pressure controller: When the input pressure reaches the set value, the instrument can control and alarm the controlled pressure through the on-off function of the output contacts.

High-switching value high-switching value: When the input pressure rises, the controller generates the pressure value when the control or alarm signal changes.

Low-switching value: When the input pressure drops, the controller generates the pressure value when the control or alarm signal changes.

Differential gap: the difference between the switching value and the low-switching value at the same set point.

Set point error: The difference between the set value and the measured actual value when the output variable is output according to the specified requirements. Set point range: Set point adjustable controller. The difference between the maximum pressure value and the minimum pressure value that can be adjusted by setting point. DIFF is pressure difference, which refers to poor handover. It is often called "disconnection difference" or "dead zone" in use. It refers to the difference between the set action value and the reset value of the switch. For example, when the set value is 1 MPa and the actual reset value is 0.9 MPa, the interruption difference is 0.1 MPa. Each pressure switch has this parameter, but some of the dead zones of pressure switches are adjustable, and some of the dead zones of pressure switches are not adjustable.

When debugging the pressure controller, first of all, we need to know whether the switching value we use is the high-switching value or the low-switching value. Whether the high-switching value of the pressure controller with adjustable switching difference needs to meet the requirements at the same time. Simply put, when the pressure is rising, or when the pressure is falling, or both need to be satisfied.

Many types of controllers have switch value calibration windows and switch difference calibration windows, but the calibration windows of such controllers can only be used as general observation, bearing in mind that they can not be used as the standard and basis for adjusting setting points. Therefore, the adjustment of the pressure controller must go through qualified laboratory adjustment. Many people feedback information, they feel that the switching value is low or high, in the absence of a standard device, "feel" or "look at the scale" to adjust themselves, resulting in a serious deviation of the switching value from the required set value.