There are 32 HV pods for each quadrant of the ICD (NE, NW, SE, SW). Each pod sends voltage to a 1:3 fanout. There are 96 channels of HV for each quadrant.
There are eight HV pods in each module, and there are six modules per crate. We need 4x32 pods or 4x4 modules. The 16 modules are housed on three crates (b, c, d) which sit in the rack MCH116.
Crate B controls power to all of the Northeast quadrant (pods NE01-32, channels 1-96), and the first half of the Northwest (pods NW01-16, channels 1-48). Crate C controls power to the second half of the Northwest (pods NW17-32, channels 49-96) and all of the Southeast (SE01-32, channels 1-96). Crate D controls only the power to the Southwest (SW01-32, channels 1-96).
If you see something different than the above image, there is a problem. Read more below on what to do if there is a trip, or if something has been turned off.
For more information, check out the ICD HV System Map.
In general, the calorimeter shifter should not modify the ICD HV settings which have been painstakingly adjusted. There is a lot of effort needed to adjust and calibrate the ICD signal, which is still being defined and must be considered an Expert Task.
However, sometimes it will be necessary to turn off or on the ICD HV because:
- Work is being done in or near racks MCH116 or MCH117. The drip detector can accidentally be triggered by moving cables, so a controlled ramping down of the HV is preferable to a sudden and potentially harmful trip. The PMTs are quite old and fragile.
- A cooling fan or power supply needs to be replaced, so the crate or rack needs to be powered down.
- Water cooling or humidity problems may cause accidental RMI trips, so the HV needs to be ramped down as a preventative measure.
Move your mouse cursor to the Crate panel on the HV Monitoring GUI. You should see a little pop-up window with the phrase: Left click to display channels. Do so.
The following HV Control GUI will pop up:
There is tab for each of the four ICD quadrants, each powered by 32 HV pods. It depends on which of the three Crate panels in the HV Monitoring GUI you clicked which determines the tab you first see in the ICD HV Control GUI. The above appears if you click on the Crate B panel, which shows the current state of voltages and currents for the Northwest ICD.
All of the ICD is now instrumented. There is only one pair of HV pods that are in the Offline state because there is no ICD material in the southeast region corresponding to the silicon/cryostat chimney.
If you click on the other three tabs (Northeast, Southeast or Southwest), you should see a display very similar to the following:
All the State cells should be Locked. All the V_Read and I_Read cells should be green (normal). If they are yellow (warning) or red (alarm), make a note in the logbook, and send email to d0icd@fnal.gov. Refer to the above snapshots to make sure the I_Max, V_Max and V_Set values are as expected.
A feature of the ICD system was noted during commissioning. The low voltage fuses are more likely to blow during the ramping up or down of the high voltage. Therefore, as a general rule of power cycling the ICD system, it is preferable to turn off the preamp power supply BEFORE ramping up or down the high voltage.
- How to turn off the HV:
- Go to the bottom and click on the button Unlock.
- At the top, click on Set HV and select 0%.
- Go to the bottom and click on the button Ramp.
- Never Turn Off any pods before ramping the voltage down to or near zero.
- Once all the values in the columns for V_Read and I_Read are at or very near zero, go to the bottom and click on the button Off.
- Do the above for all four quadrants, chosen by the tabs Northeast, Northwest, Southeast and Southwest.
- How to turn on the HV:
- At the top, click on Set HV and select 100%.
- Go to the bottom and click on the button Ramp.
- The values in the columns for V_Read and I_Read should increase and the status cell will be yellow with the words Ramping or Average.
- When the status cell changes to Holding for all cells that are On, go to the bottom and click on the button Lock.
- Do the above for all four quadrants.
- How to reset the HV if it has tripped:
- Go to the ICD HV Control GUI (see above if you need to open one).
- Click through the four tabs to find the HV pods where the status cell is flashing red.
- Click on the cell with the left mouse button and choose Reset. If there are multiple trips, go to the bottom of the GUI and click on Reset. This should change the state to On.
- Go to the bottom and click on the button Ramp.
- The values in the columns for V_Read and I_Read should increase and the status cell will be yellow with the words Ramping or Average.
- When the status cell changes to Holding for all cells that are On, go to the bottom and click on the button Lock.
- Make a note in the logbook and send email to d0icd@fnal.gov.
I have setup up scripts to launch StripTools of all the ICD currents and voltages. They are set with a circular buffer of some finite number of seconds, so one can go back in time to see why something tripped. I have fit eight current or voltage readings per StripTool, and I have written scripts so one can look at one quadrant at a time. To view all the ICD currents (or voltages) at the same time, one can launch a single "all" script, but this will generate sixteen separate windows stacked on top of each other, so you will need to space them out in order to view them all simultaneously. The default window shows the last five minutes with a resolution of one second. We are still trying to understand the behavior. The currents read from the ICD HV SW crate have an oscillating feature which appears to be real.
You need to be logged into d0ol06 (as d0icd, d0cal, d0run)
Type the following:
setup d0online
Four stacked windows like the following will open:
cd /home/d0icd/hv/
./ICD_NE_CurrentStripTool &
From the same directory, you can also try:
./ICD_NW_CurrentStripTool &
./ICD_SE_CurrentStripTool &
./ICD_SW_CurrentStripTool &
Or, you can generate all StripTool charts of all currents by typing:
./ICD_CurrentStripTool &
There are six buttons on the bottom which allow you to:
- Pan left
- Pan right
- Zoom in
- Zoom out
- Auto scroll
- Refresh
I have set the upper and lower limits for each channel in my script such that increasing current draws that lead to a trip can be seen. Alternatively, a trip may be caused by something very sudden. I don't know. As long as a trip can be spotted and recorded shortly after it happened, we can go back and look in the StripTool.
Watching the voltages is not as fascinating, and as a rule, you don't need to have them open. But, in the event you do want to open the ICD voltage StripTools, type the following:
setup d0online
cd /home/d0icd/hv/
./ICD_NE_VoltageStripTool &
The syntax is the same as for the currents if you wish to look at other quadrants or all ICD voltages at once.
Only as long as the StripTools have been open can we look back in time to see the current or voltage behavior. So, if you noticed that the StripTools have been closed, please relaunch them. They should also be added to the start-up procedure for the Calorimeter/ICD console (d0ol06).
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Last modified: Wed Dec 19 19:23:12 CST 2001
Web page maintained by Alan L. Stone: alstone@fnal.gov |