ABB Pulse Encoder Input Unit

General information and instructions

These instructions are an important part of the product and

must be retained for future reference.

Installation, commissioning, and maintenance of the product

may only be performed by trained specialist personnel who have

been authorized by the plant operator accordingly. The specialist

personnel must have read and understood the manual and must

comply with its instructions.

For additional information or if specific problems occur that are

not discussed in these instructions, contact the manufacturer.

The content of these instructions is neither part of nor an

amendment to any previous or existing agreement, promise or legal relationship.

Modifications and repairs to the product may only be performed

if expressly permitted by these instructions.

Information and symbols on the product must be observed.

These may not be removed and must be fully legible at all times.

The operating company must strictly observe the applicable

national regulations relating to the installation, function testing,

repair and maintenance of electrical products.

The detector signal is spectrally decomposed into frequency components 

at harmonics of the laser modulation frequency.

The second harmonics of the signal is used to measure the

concentration of the absorbing gas. The line amplitude and line width are both

extracted from the second harmonics line shape, which makes the measured

concentration insensitive to line shape variations (line broadening effect) caused

by background gases.

NOTE: The AO2000-LS25 measures the concentration of only the FREE

molecules of the specific gas, thus not being sensitive to the molecules bound with

some other molecules into complexes and to the molecules attached to or

dissolved in particles and droplets. Care should be taken when comparing the

measurements with the results from other measurement techniques.