The VELO HV project controls the whole Velo High Voltage system; it runs on vedcs01w (windows) under the velo_user account.

How to Switch on High Voltages

  • From the VELO:TOP window open the main HV panel (VELO_HV:TOP)

  • Select from the State button the recipe you require:

    • Go_OFF - turns off the HV, ramping down

    • Go_STANDBY1 - apply 10V, ramping up

    • Go_STANDBY2 - apply 50V, ramping up

    • Go_READY - apply 100V, ramping up

    • Do_Emergency_OFF, ramping down

    • Load - this is not needed

Using the top most state button this can be issued for the whole detector

Using the VELOA_HV (VELOC_HV) state button this can be issued for the A (C) side only.

After selecting the recipe confirm this by pressing "send" on the pop-up window.

Note, these commands are issued to the Pile-Up detectors also.


How to Switch on High Voltages on a set of 8 channels (one board)

The VELO power supply modules are split into boards, each board controls 8 channels.

  • From the VELO_HV:TOP panel, select VELOA_HV (or VELOC_HV)

  • The VELOA_HV panel is then displayed, the state buttons for individual boards can then be used to issue recipes, see the instructions for "How to turn on all high Voltages"


How to Switch on High Voltage on a single channel

* From the VELOA_HV (or C) panel, select the board that contains the cahannel you wish to control. For example BOARD00, displays the window VELOA_HV_BOARD00:TOP

* BEFORE controlling the channel the recipe must be loaded (this differs from the board level, or all velo level instructions). Use the state button of the ConfDB to do this. For example select VELOA_HV_BOARD00_ConfDB and select LOAD.

* Use the state button of the corresponding channel, for example VELOA_HV_BOARD00_CH03, to then select the state you wish (e.g. STANDBY1)

* (the VELOA_HV_BOARD00_MA00 controls the whole board)


How to Perform an IV Scan (or consult previous scan results)

  • Open the panel of the board (set of 8 channels) for which you wish to perform the IV scan. (The IV scan can only be performed on 8 channels at a time). For example use the VELOA_HV_BOARD00:TOP panel.

  • Click on the IV scan button (bottom right), this displays an IV scan panel.


  • Select the first channel to scan

  • A filename is automatically suggested (look in the frame), replace the question marks with the current temperature (the temp NTC can be obtained from the VELO top summary page).

  • Click on the ADD button to save the file name (if you don't add it, it won't be saved!).

  • You can also display the results of a past scan for the same slot: select the corresponding channel and then choose
one of the suggested files. the suggested files are chosen from the directory indicated above. alternatively browse a directory by clicking the folder icon.

  • Select the next channel to scan and repeat the points above, to choose the file name, add the filename, and select previosu scans

  • set the ramp rate, final high voltage value and step value.

  • Push the START button to perform the scan, or just plot the results of a previous scan.


How to recover from an OPC Server Crash (part 1)

The OPC server is the level of software that sits between PVSS and the power supply module. This server crashes every few days, and can be recovered following these instructions.

  • logon to Vedcs01w as velo_user

  • If the OPC server has crashed the following message will be displayed

OPC crash

  • Click OK, the OPC server should now restart.

  • Check this by following "How to check the OPC server is running", if not then try again, then follow "How to recover from an OPC Server Crash (part 2)"

How to recover from an OPC Server Crash (part 2)

If "How to recover from an OPC Server Crash (part 1)" does not restart the OPC server, then do the following

  • go to the PVSS 3.6-SP@:console window and scroll down to find the OPC DA Client 8 (must be number 8!).


  • Click on the OPC DA client 8 and then use the forced kill icon (the red on/off type button) on the right column of the window. confirm this kill in the pop up window.

  • also check that the process is no longer running with the windows task manager, and if it is running kill this also.
do this by going Start -> TaskManager -> processes -> look for isegHVOPCServer.exe, and if it is there stop the process.

  • restart the process on the console window by clicking on OPC DA client 8 and pressing the top green start icon on the right column of the window.

  • Now check that the OPC server is running, see "How to check the OPC server is running"

How to check the OPC server is running (Part 1)

The VELOA_HV:TOP and VELOC_HV:TOP both display the "CAN HeartBeat". This heartbeat will stop if the OPC server dies, and the instructions to restart the OPC server should be followed. The hearbeat should be a continuosly increasing number.

How to check the OPC server is running (Part 2)

These instructions show how to check the OPC server is running WITHOUT using the FSM

From the Device Editor Navigator window (for example on Vedcs01w)

Go to Hardware Tab -> VEDCSHV -> ISEG ->CAN0, click to diplay a new window, that is shown here


check that the "OPC server heartbeat" is constantly increasing number.

If not, the OPC server has crashed and needs to be restarted.

How to access the Device Editor and Navigator

From MyComputer open G:\online\ecs\Shortcuts\VELO then select VEDCSHV_UI_DEN

From the Device Editor and Navigator the VELO A or c side HV top panels can be accessed directly by selecting the FSM tab -> VELOA_HV or VELOC_HV, right click and select view

How to recover from a current trip

Do not attempt to recover from a trip unless you understand what caused it. If in doubt call an expert.

If a VELO HV channel draws a current above the software limit set for this channel it will undergo an I trip.

To recover this

  1. open the panel of the corresponding channel, a red Itrip alarm will be displayed
  2. Turn the channel off and wait till its status has changed to off.
  3. Press the Clear Alarm button

This is shown on the following screenshot. HV_trip_Error.JPG

How to know which channel you are controlling (naming conventions)

The VELOA_HV panel lists the channels in two numberign conventions. It gives the slot number and the high voltage channel number.

The slot numbers are for example PU01_AB for Pile-up (PU) 1st (01) Aside (A) Bottom repeater board (B) VL06_AT for Velo (VL) 6th (06) Aside (A) Top repeater board (T). There are some spare channels on the HV which are listed as "undefined" in this convention

The high voltage channel numbers are listed by board number and channel number for example VELOC_HV_BOARD02 ch 03 The channels are numbered 00 to 07 (8 channels) on each board.

Physically there are two boards on each power supply module, i.e. each module has 16 channels. Board00 and Board01 belong to the same power supply module (similiarly 02/03,04/05 separately for either A or C side) The 6 power supply module sfor the whole velo are in the same crate in D3.

The full connectivity is described in the "VELO ECS/LV/HV connectivity" document and the full HV chain in the "HV connectivity" note which are linked on the main Twiki HV page.

-- BarinjakaRakotomiaramanana - 06 Aug 2008

Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg Console_Panel.JPG r1 manage 57.8 K 2008-08-06 - 10:28 BarinjakaRakotomiaramanana  
JPEGjpg Device_Module.JPG r1 manage 39.2 K 2008-08-06 - 10:08 BarinjakaRakotomiaramanana  
JPEGjpg HV_scan_1.JPG r1 manage 141.4 K 2008-08-06 - 13:12 BarinjakaRakotomiaramanana  
JPEGjpg HV_scan_top.JPG r1 manage 119.8 K 2008-08-06 - 12:29 BarinjakaRakotomiaramanana  
JPEGjpg HV_top.jpg r1 manage 36.2 K 2008-08-06 - 11:21 BarinjakaRakotomiaramanana  
JPEGjpg HV_trip_Error.JPG r1 manage 28.2 K 2008-08-12 - 18:29 ChrisParkes  
JPEGjpg OPC_crash.JPG r1 manage 16.0 K 2008-08-06 - 09:48 BarinjakaRakotomiaramanana  
JPEGjpg VELOA_HV_BOARD_TOP.JPG r1 manage 106.1 K 2008-08-06 - 12:02 BarinjakaRakotomiaramanana  
JPEGjpg VELOA_HV_TOP.JPG r1 manage 154.3 K 2008-08-06 - 11:55 BarinjakaRakotomiaramanana  
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