The Widget

Figure 7.14 displays the Scan Device Selection menu.

Figure 7.14: The Scan Device Selection

 The Counter/Timer frame

 Timer: t1 The menu button displays the selected timer. It can be clicked to display the available timers.

 Preset mode This flag determines whether the device is operated as an ordinary timer or a preset timer (constant flux). An ordinary timer opens a gate for sample time seconds. A preset timer loads an internal register with some value and waits for an external signal to decrement the register contents. The gate is open as long as the register is non-zero. The preset value is supplied by the user in the same entry widget as the sample time.

If the elapsed wait time exceeds WAIT_TIME_PRESET_MAX, the wait state is terminated and ONLINE waits for TIME_HEATUP seconds (default 30) before it re-measures the last point. This procedure has been implemented for injection recovery.

 Sel.: Counters are seleted for measurements, if buttons in this column are activated.

 Dis.: An activated button in this column indicates that a selected counter is displayed.

 Flux counter: This counter is used by the Automatic Beam Shutter Option. If the option is enabled and the flux counter falls below the minimum count rate, Online enters a wait state until the beam returns.

 Min. count rate: This number is used by the Automatic Beam Shutter Option. If the option is enabled and the flux counter falls below this value, Online enters a wait state until the beam returns.

 Heatup Time: This parameter shadows the symbol TIME_HEATUP. It is used by the "Automatic Beam Shutter" option. Online waits as many seconds to heatup the optical components after the beam returns. Be sure to update the symbol TIME_HEATUP in exp_ini.exp, if you changed it here.

 Normalize counts: The counter readings are divided by the sample time before they are stored.

 Measure offsets: Since the counters get the input mostly from VFCs, offsets need to be measured.

 Clear offsets: Offsets are set to 0.

 The MCA/SCA frame

 MCA Timer: The timer that gates the ADCs.

 MCA1 ADC_MCA Enables the MCA

 2048: The no. of channels can be selected.

 zip MCA Files: MCA data is stored in a subdirectory. This flag determines whether the contents of the directory is zipped.

 Logarithmic Scale: MCAs can be displayed on a logarithmic scale.

 SCA1: The user may specify regions of interest that define the limits of software SCAs.

 SCA-SUM: If selected, a SCAN is created that stores the sum of the SCA SCANs.

 Net SCAs: A simple linear background subtraction. The first an the last point of an ROI is connected. All entries below this line are subtracted.

 The Encoder frame

 HHE1 The encoder positions are read, displayed and written to the disk file.

 The Virtual Counter frame

Virtual counters can be selected like other counters. Details can be found in section 7.2.2.

 The Extra Code frame

When the user starts a scan, Online creates the scan scripts before_auto_scan.pl, during_auto_scan.pl and after_auto_scan.pl according to the selected devices. It may occur that the device selection is not sufficient to cover the needs. Therefore the extra code feature has been introduced. Click on the buttons to edit the extra code lines. Section 7.2.4 gives more information.

 The Profiles menu

Configurations of selected devices can be stored and loaded.

 The Debug menu

This menu offers the opportunity to inspect the scan scripts. The scripts updated before the display windows opens.

If the checkbutton Disable macro update is enabled, Online does not create new scan macros are when a scan starts. Instead it executes the current versions of before_auto_scan.pl, during_auto_scan.pl and after_auto_scan.pl as they are in ~/prog. You may want to edit these files to include some debug statements.