Signal damping - PR-33 - PR-33-S

PR-33-S User Guide

Document code
Document type
User guide

The system provides the possibility to enter signal damping to diminish the influence of process noise. The damping is applied to the CONC value (and thus the output signal).

The PR-33 offers two types of signal damping. Exponential (standard) damping works for most processes and is the standard choice for slow and continuous processes. However, if the process has fast step changes, linear (fast) damping gives shorter settling time.

The damping time is set separately. What the damping time means in practice depends on the damping type:

  • With exponential damping, the damping time is the time it takes for the concentration measurement to reach half of its final value at a step change. For example, if the concentration changes from 50 % to 60 % and damping time is 10 s, it takes 10 seconds for the refractometer to display concentration 55 %. A damping time of 5 … 15 s seems to work best in most cases.
  • With linear damping (fast damping), the output is the average of the signal during damping time. After a step change the signal rises linearly and reaches the final value after the damping time.

The following figures show how the damping time affects the measurement.

The factory setting for damping in PR-33-S is 5 s linear. Avoid overdamping, the signal should not be made insensitive.
Figure 1. Exponential damping
Figure 2. Linear damping