# HV Edit

Overview

The purpose of the HV Edit application is to display and set high voltages in an experiment. It does this by connecting to a MIDAS online database and using the names, demand and measured values of this database.

Although it is possible for the application to set the demand values as a standalone program, it is necessary that a front-end program is running on a computer which is physically connected to the high voltage power supply.

It is possible to start the HV Edit application on several computers simultaneously. Any change made by one of them is automatically reflected in all of them.

Usage

Upon startup, the program must connect to a MIDAS online database. Usually, the database where the application was connected the last time is used. This information is stored in HVEDIT.INI in the windows directory. It is possible to overwrite this setting by specifying a TCP/IP host and an experiment name as command line parameters.

After successful connection to the database, a list with all channel groups is displayed in the upper left list box, where the user may select individual groups, which are then displayed in the lower left list box:

{bmc layout.bmp}

To change one ore more channels, select them in the list box and use the input area. To select more than one channel, press and hold down the Shift-Key or Control-Key when clicking on channels.

The buttons have following meaning:

HV off / HV on	Using this buttons cause the HV front end to switch on and off the whole HV crate. Before working at the experiment, it is a good practice to switch the HV off.
	
Input	Enter voltage values in this field. Previously entered values can be retrieved by using the drop-down box (the down arrow at the right end).
	
+1 .. -10	This buttons increment or decrement the currently selected channels.
	
Zero	Set selected channels to zero, but store their previous values in an internal restore buffer.
	
Restore	Restore previously zeroed values from the internal restore buffer.
	
Save / Load	Save / Load all channels to / from a local file.
	
Print	Print values of selected  group.
	
Configure	Configure the program.
	
Help	Show this help screen	

Stefan Ritt, 28. Nov. 1995

#K $Program configuration

The program configuration dialog box is used to select the MIDAS online database and to edit channel names. Enter the TCP/IP host name where the experiment is running and its name. Use the Edit channel names button to change the names of individual channels. Channel names consist of a group name and a channel name separated by a “%”. Thus, Beam counters%B1 is channel B1 of the group Beam counters.

#K $MIDAS Online Database

The MIDAS Online Database is a central storage of all experiment-relevant information. Clients can “connect” to this database via TCP/IP and set or retrieve information. In a typical experiment, several front-end computers acquire data and store it in the database, while applications like HV Edit display the measured values or change the demand values.