## Special POLDI scan command

Additionally a special POLDI scan command was programmed which offers the possibility to scan variables (motor) against detector count rate. For this purpose the 400 detector cells are divided into 4 groups (5-100, 101-200, 201-300, 301-395) where the count rates (stored in the histogram memory) are added.

The command syntax for the POLDI specific scanning is like this:

> scanhm var start delta np preset

All parameters must be specified. The parameters and their meanings:

- var start delta This is how the variables to scan are specified. For each variable scanned the name of the variable, the start value and the step wide must be given.
- np is the number of points to scan.
- preset is the preset to use for the counter. As the counter mode, the mode timer is predefined.

The scan data are saved in ASC-format in the directory /home/POLDI/scan. Additionally the typical NeXus-files are available for each step of the scan. The NeXus files are saved in the directory /home/POLDI/data/2002.