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Usage

This GUI is used to set the high voltages (HV) of a midas experiment, especially the low energy muon spin rotation (LEmuSR) experiment at PSI. The functionality is rather straight forward and hence the different menus are going to be explained only very briefly.

The startup syntax is:

   hvEdit [--help | -h hostName -e expName]

where hostName is the name of the host computer running the MIDAS high voltage experiment, expName is the name of the MIDAS experiment.

Menus

  1. Open
  2. Save
  3. Print
  4. Exit

This will disconnect 'hvEdit' from the current experiment and flash the GUI.

Open

An open dialog pops up were one can choose from predefined HV settings. They are device specific and therefore only a HV table for this specfic device will be loaded. Details about the structure of the 'hv'-files are found under 'Technicalities'.

Save

A current HV setting can be saved to a file. The file name has to look like deviceName_whatever.xml, e.g. fug-18kv_nosample.xml (for details see 'Technicalities').

Print

Prints the current 'HV/Current Limit' settings of the shown device.

Exit

Closes the connection to midas properly, before exiting the program.

Buttons

HV/Current Limit Tabs

For each device a tab list exists. In the 'HV' tab the HV informations are shown. Only the column 'HV Demand' is not read only, i.e. here by click onto a cell the value can be changed interactively. The same can be achieved by using the 'Input:' field together with the 'Set' button (to the right of the tabs). Analogous the 'Current Limit' tab shows the informations related to current. Here only the column 'Current Limit' is editable. The editable columns allow multiselect of cells, i.e. with mouse cursor whole regions can be selected, the 'shift' key together with the keyboard allow the same. By pressing 'ctrl' multiselection of disjointed cells can be selected. In case of multiselection the value has to be changed via the 'Input:/Set' facility.

Device list

Here the list of all the available HV devcies of the experiment are shown. To switch from one device to another, just select the corresponding name and the HV/Current Limit tabs will switch.

Host/Experiment

This fields show the connection informations, host name and the chosen experiment. It serves only as an information.

Switch All Channels Off

Switches all the HV channels off, i.e. all channels of all devices are going to be set to zero! This is a usefull HV emergency exit, so to speak.

Set HV values

The 'Input' field and the 'Set' button are one unit. A value entered will change the selected cells of 'HV Demand' or 'Current Limit', only if the 'Set' button is going to be pressed. This is a measure of precaution against nervous guys.

Increments

The buttons -1.0, -0.1, ... are HV increments in units of (kV). They act on the selected cells of 'HV Demand'.

Zero

This switches the selected (see HV/Current Limit tabs) to zero. The cell of the 'HV Demand' table is multi selective.

Restore

Restores the value of the selected 'HV Demand' cells to their last value.

Select All

Select the whole 'HV Demand' column of active device.

Scale by factor

Scales selected HV demand elements by the factor given in the text field.

Technicalities

hvEdit is using a XML startup file in order to get the MIDAS ODB pathes and hvEdit specific settings. The name of this XML startup file is assumed to be hvEdit-expName.xml where expName is the MIDAS experiment name, e.g. hvEdit-example.xml. This XML startup file should be placed in the directory $HVEDIT_ROOT/bin/xmls. $HVEDIT_ROOT is the directory where hvEdit shall be installed (see also the hvEdit.pro file for details). The notation $HVEDIT_ROOT is only used for convenience, no system variable with such a name is needed.

The file 'hvEdit-expName.xml'

The file hvEdit-expName.xml is going to be read at the startup of 'hvEdit'. It should be placed in $HVEDIT_ROOT/bin/xmls. If hvEdit-expName.xml does not exist, some hardcoded default values will be tried, which will not always work properly. hvEdit-expName.xml serves as an startup administration file in which path information etc. are stored. The XML syntax tags of the file are:

An example XML startup file is:

<?xml version="1.0" encoding="UTF-8"?>
<hvEdit-generic xmlns="http://midas.web.psi.ch/hvEdit-generic">
<comment>
hvEdit is looking for this file under $MIDASSYS/gui/hvedit/qt-3.3/hvEdit/bin/xmls
where $MIDASSYS is the source directory of midas

general: general settings for hvEdit
default_settings_dir: the path to the hv settings files
default_doc_dir: the path to the hvEdit help files
termination_timeout: timeout in (min). If within this timeout there is no user action,
hvEdit will terminate. Setting termination_timeout to a negative
number means that this feature will be disabled.
demand_in_V: flag showing if the demand HV's are in V (true) or kV (false)

odb_key: MIDAS online data base (ODB) pathes or realtive pathes
hv_root: ODB path to the HV root. Various HV roots are allowed, though the
number must be entered in the general section with the label
no_of_hv_odb_roots.
hv_names: relative ODB path where to find the channel names
hv_demand: relative ODB path where to find the hv demand values
hv_measured: relative ODB path where to find the hv measured values
hv_current: relative ODB path where to find the measured currents
hv_current_limit: relative ODB path where to find the current limits
</comment>
<general>
<default_settings_dir>/home/nemu/midas/midas-1.9.5/gui/hvedit/qt-3.3/hvEdit/hv_settings</default_settings_dir>
<default_doc_dir>/home/nemu/midas/midas-1.9.5/gui/hvedit/qt-3.3/hvEdit/doc</default_doc_dir>
<termination_timeout>15</termination_timeout>
<demand_in_V>true</demand_in_V>
</general>
<odb_keys>
<hv_root>/Equipment/HV</hv_root>
<hv_root>/Equipment/HV Detectors</hv_root>
<hv_names>Settings/Names</hv_names>
<hv_demand>Variables/Demand</hv_demand>
<hv_measured>Variables/Measured</hv_measured>
<hv_current>Variables/Current</hv_current>
<hv_current_limit>Settings/Current Limit</hv_current_limit>
</odb_keys>
</hvEdit-generic>

The 'hv'-file structure

'hvEdit' can read default HV settings from files with the extension 'xml' (in fact, it is a XML file). These files do have the following XML key words:

An example for such a 'hv'-file is:

<?xml version="1.0" encoding="ISO-8859-1"?>
<HV xmlns="http://nemu.web.psi.ch/HV">
<comment>
chHV in (kV),
chCurrentLimit in (mA)
</comment>
<hvDeviceName>
TD
</hvDeviceName>
<hvCh name="C_Foil">
<chNo>1</chNo>
<name>C_Foil</name>
<hvDemand>-3.73</hvDemand>
<currentLimit>0.001</currentLimit>
</hvCh>
<hvCh name="Front">
<chNo>2</chNo>
<name>Front</name>
<hvDemand>-3.54</hvDemand>
<currentLimit>0.001</currentLimit>
</hvCh>
<hvCh name="Back">
<chNo>3</chNo>
<name>Back</name>
<hvDemand>-3.95</hvDemand>
<currentLimit>0.001</currentLimit>
</hvCh>
<hvCh name="MCP3">
<chNo>4</chNo>
<name>MCP3</name>
<hvDemand>-3.35</hvDemand>
<currentLimit>2</currentLimit>
</hvCh>
</HV>

 
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