Interlaced Mode

The interlaced mode gives the possibility to achieve higher angular resolutions combined with high scan frequencies. If an interlaced mode is selected, the LMS5xx device generates a sequence of two or four scans. The first scan of each sequence is a normal scan with a specific angular resolution and start angle.
The following scans of the sequence are shifted by a certain angle, compared to the first scan.
 

The first scan of a sequence has one more scanpoint than the other scans of a sequence.
This makes it possible for the user to create one scan out of an interlaced-sequence.
The LMS5xx will send one telegram after each single scan (rotation) is completed. It does not merge the individual scans of a sequence into one telegram.

For the field evaluation the LMS5xx merges internally the interlaced sequence into one internal telegram. This data telegram is then used internally to evaluate the fields.
This telegram is not available externally for customers.

The Field Evaluation Monitor shows the merged data of an interlaced sequence.
The ScanView shows the individual scans, similar to the LMDscandata which is sent to the customer's controller. Usually the jitter of the angular position of the scan points can be recognized.

To parameterize the interlaced mode in SOPAS ET, just go to basic settings and select the corresponding interlaced-configuration in the drop-down menu.

The interlaced mode can be activated by using the normal telegram "mLMPsetscancfg" with scan frequency and angular resolution as its parameters. If the device can set itself  on the requested combination of scan frequency and angular resolution only in interlaced mode, then the interlaced mode is activated.
If the combination is possible without interlaced mode, the interlaced mode is deactivated.

The angular resolution of a single scan is 1°. This is shown in the following figure.

To raise the angular resolution by using 2x interlaced mode, every second scan is shifted by 0.5° to the previous scan. Each of the scans has an angular resolution of 1° but combined, the angular resolution is 0.5�. The shifted scan contains one scanpoint less than the previous one as shown in the following figure.

By using the 4x interlaced mode, 4 scans with an angular resolution of 0.6667° are shifted by 0.1667° to each other which gives a combined angular resolution of 0.1667°. The sequence is as shown in the figure below. In this case, scan1 contains one more scanpoint than the following 3 scans.