Measurement - PR-33 - PR-33-AC

PR-33-AC User Guide
Document code
M212411EN
Revision
B
Language
English
Product
PR-33
PR-33-AC
Document type
User guide

The following table describes the measurement messages and their related actions.

Table 1. Measurement messages
Message Description Corrective action
OUTSIDE LIGHT ERROR or OUTSIDE LIGHT TO PRISM The measurement is not possible or is disturbed because outside light reaches the camera. Identify the light source and block the light from getting to the prism at the sensor tip. The amount of outside light can be seen at BGlight on the Diagnostics page.
NO OPTICAL IMAGE The prism is heavily coated. Remove sensor from line and clean prism manually.
There is moisture condensation in the sensor. See Hardware.
The sensor temperature is too high.

The light source is faulty. When the sensor is removed from the process, the yellow flashing light can be seen through the prism.

The light is only visible at an oblique angle.

Check the LED value on the Diagnostics page. For more information, see Diagnostics.

If the value is clearly below 100, LED fault is not likely.

If the value is above 100, contact Vaisala.
There are negative spikes in the optical image. The probable cause is dust or fingerprints on the CCD window. Contact Vaisala.
The CCD card in the sensor is faulty.
PRISM COATED The optical surface of the prism is coated by the process medium or impurities in the process medium.

Remove sensor from line and clean prism manually.

If the problem is recurrent, consider improving the flow conditions. For more information, see Choosing refractometer mounting location.
LOW IMAGE QUALITY The most likely cause for this message is coating on the prism. There still is an optical image available, but the measurement quality may not be optimal.
NO SAMPLE The operation of the equipment is OK but there is no process liquid on the prism. In some cases this message may also be caused by coating on the prism.
TEMP MEASUREMENT FAULT Indicates faulty temperature element.

Contact Vaisala.

A difference to some other process temperature measurement is not a fault. The Sanitary OEM Refractometer shows the true temperature of the prism surface.
Concentration drift during Normal operation For drift upward or downwards to zero, cause is likely the prism coating.

Remove sensor from line and clean prism manually.

If the problem is recurrent, consider improving the flow conditions. For more information, see Choosing refractometer mounting location.