Author: Chris Smith
Date: 29th September 2001
Version: 1.1

Turning off the High Voltage

· The HV PC is on the middle level, on the west side of the cavern and is labeled “HV PC” for those who are morons. 

· In the terminal window there should be a prompt:
|HV|MF3>

This is the hv program prompt. The number, which may be 1,2,3 or 4, refers to the current mainframe that the program is talking to. (n.b. the mainframes are the 4 large blue LeCroy boxes 2 of which are next to the HV PC on the westside. The other 2 are directly opposite on the eastside.)

· Currently, HV is connected only to mainframes 1 and 3. These must BOTH be switched off before leaving at 3.30am.

· To turn off the HV to mainframe 1 type the following commands at the prompt:

|HV|MF3> mainframe 1 <enter>
|HV|MF1> zero <enter>
|HV|MF1> off <enter>

The program will ask you if you really want to disable the hv to the mainframe, say “yes”. The voltages will then be ramped down and tables of all the channels will scroll past the screen.

The program will give warnings if the hv values set are different to the default, so don’t be surprised when the program warns you of multiple errors. Just ensure that in the final column “actual”, the value is 0 for all channels.

The hv is then off. To double check, when the hv is enabled a bright red light on the back of the mainframe is on. This should now be off.

· Repeat the procedure for mainframe 3.

· The power to the mainframes can then be switched off by hitting the large white switches on the front of all the mainframes.

Reading the High Voltage Values

If at anytime the mainframes are on and you are unsure of the hv status on mainframe x, at the prompt type:

|HV|MF1> mainframe x <enter>
|HV|MF1> read <enter>

A table will then scroll down the screen showing the various channels. The important columns are the last three which are the default, the set and the actual values for each channel.