Pipe Nominal Diameter

This means the size of a pipe. Three types of names are given to indicate nominal diameter, namely, common name, name A, and name B.

Polygon mirror (Scanning method)

An equilateral polygonal prism which has reflecting surfaces (mirrors) is rotated to deflect a light beam orthogonally to its rotation axis. Generally, the number of reflecting surfaces ranges from six to fourteen. The more surfaces, the more target scans per rotation, allowing higher-speed scanning. However, the deflection angle decreases and the scanning width narrows. Based on the scanning width and scanning rate, the KEYENCE LS-5000 Series uses a 12-surface mirror.

Post-trigger

A function which delays sampling of data by the specified number of points after the trigger point.

Power Spectrum

The amplitude information of each frequency. Unlike real display, the power spectrum is the average of the second power of a value for smoothing irregularities. The value is obtained by 20log√（R2 + I2).

Preset value/preset function

When the count reaches the preset value, the control output turns ON.

Pressure Loss

When liquid flows through a certain segment, the energy of the liquid is lost due to friction against the internal wall of the pipe, changes in pipe shape, diversion of flow, merge of flow, and internal obstacles, etc. The pressure loss is represented as the difference of total pressure at the beginning and end of the segment.

Pre-trigger

A function which samples data before the trigger point by a specified number of points.

Programmable Logic Controllers (PLC)

Programmable logic controllers are considered to be a large group of relay contacts (N.O., N.C.), timers and counters. These elements are combined with various instructions to make sequential circuits. The sequential circuits are software-based logic circuits, not hard-wired circuits such as electromagnetic relay circuits.