In-line refractometer sensor - PR-21-S

PR-21 Series User Guide

Document code
IM-EN-PR21S
Revision
C
Language
English
Product
PR-21-S
Document type
User guide

The process refractometer sensor is shown in Figure 1. The measurement prism (A) is flush mounted in the oblique surface near the tip. The light source (B) is a light emitting diode.

The process refractometer uses a CCD element (C) which has 3648 photocells in a row integrated on one chip.

Figure 1. Sensor structure

The image detector output is a pulse train, as shown in Figure 2. This number of high pulses corresponds to the position of the shadow edge in the optical image. The number of high pulses is a direct measure of the critical angle. The sensor processor card (E) receives the raw data from CCD element (C) and the temperature probe (F).

The digital image sensor (C) is separated from the process heat by fiber optics (D) and the thermal isolation (G). It is housed in the air-cooled sensor head.

Figure 2. Image detector system