Primes HP-MSM-HB Скачать руководство пользователя страница 119

Страница: 119 / 149

119

Revision 00 EN - 01/2021

HP-MSM-HB

35,0(6

24.3.9

Caustic measurement (menu

Measurement > Caustic

)

The caustic measurement is a serial measurement where the z position is varied. The results are stored in
different planes. A different z-position is assigned to every measuring plane. As the beam radius as well as
the power density change in every z-position, the position as well as the size of the window and the signal
strength can vary from plane to plane. The parameters are automatically adjusted in the process and can
also be configured separately for each measuring plane.

Parameters (start number of the plane)

Under Start, the start number at which the measurement is initiated can be entered for the plane. By default,
the start number is generally set to zero and should only be changed when you are measuring in an existing
document and don’t want the existing measurement data to be overwritten. If, for example, you have mea-
sured a caustic with 21 planes and want to magnify the measuring area to the smaller z-values, you can set
the start plane to 21 and modify the measuring area appropriately. The new measuring values will then be
written into the existing document starting with plane 21.

In the Quantity selection field, the number of planes to be measured in the specified z-range is set. The fol-
lowing should be considered here:

• Since the LaserDiagnosticsSoftware LDS always sets the measuring plane distances so they are equi-

distant (equal spacing) and the measuring area is almost always situated symmetrically around the focal
point, an odd number of measuring planes should be selected. This ensures that the focus plane is
measured.

• Beam measurement norm DIN 11146 specifies that at least 10 measuring planes should be measured.

Furthermore, five measurements should also be taken within a Rayleigh length and the other beyond 5
Rayleigh lengths. In order to meet all of the requirements with equidistant distribution, at least 17 mea-
suring planes must be measured in a range of ± 3 Rayleigh lengths.

Mode (automatic and manual settings)

There are two different measuring modes for caustic measurement. In “Automatic” mode, the measuring
system and the LDS determine the ideal measuring window position (x- and y-direction) for each measuring
plane and the optimal measuring window size for the fill factor. Furthermore, the plane location in the z-direc-
tion is also calculated based on the specifications (number of measuring planes, measuring limits z-direction).

Especially when adjusting the measuring window size and the measuring window position in the x-
and y-direction, the number of iterations (max. three per plane) can result in an extended measure-
ment duration.

It is therefore possible to change the measuring mode to “Manual Settings” for recurring measuring tasks
and for repeating measurements. In this case, the measuring system will take the measuring window posi-
tions and measuring window sizes from the previous measurement or from a .ptx file. This reduces the mea-
surement duration considerably, but does require that the location and parameters of the laser beam change
only minimally.

Beam search

This selection field specifies which plane the caustic measurement should be started in. If the optional

Beam

Find

function is activated in the

Options

dialog window, that is also the plane in which this function will be

performed. When the Beam Find function is deactivated, this plane must be manually measured ahead of
time to make sure that the laser beam is found.

The window can be adjusted under the

Adjust

menu point. The settings for spacial resolution of the beam

search, the threshold value, and the minimum signal strength can be entered under the