Jefferson Lab Experiment E91-016

Helium Target Reboot

There are 2 IOC's used in the target control system.

vmec4: contains all the important target controls and most of the database.
vmec15: contains the records that talk to the Central Helium Liquifier (CHL) and the End Station Refrigerator (ESR) -- where we get our coolant from.

The more important of these IOC's is of course vmec4. If vmec4 gets ill, we have to carefully reboot the system. If vmec15 gets ill, then it can be easilly rebooted without affecting the stability of the cryotarget.

Call MCC ask for BEAM OFF -- Very Important.

Leave the auxillary heaters OFF. They are not needed for the helium target and already a slight misadjustment can lead to a target vent.

Turn OFF the high power heater.

Select the TGT IOC (vmec4) setting (POSITION 1) on the PIVOT reboot switch located in the Hall C counting house electronics room.

Press the Reboot button for the TGT IOC (vmec4).

The IOC will now start rebooting. Several things will happen:

The Alarm Handler will go off with INVALID alarms on most of the records (the records are no longer there).
Both the tgt and tgtcharts GUI's will have messages pop up indicating the loss of connection to database records. Acknowledge these messages.

While waiting for the IOC to reboot, reboot the tgt and the tgtcharts GUI's. If you don't do this, they may not connect properly to the IOC and you may think that they are working but in fact you have GUI illness.

While waiting for the IOC to reboot, pull up the Alarm Handler display and watch the alarm states. During the reboot, they will all be INVALID. As the IOC finishes rebooting and the database is reestablished, the alarms go out of the INVALID state. Some of them will go to yellow or red because the alarm limits are no longer correct. The IOC is probably finished rebooting when the IOC opmode alarm goes to the the red state. The whole reboot process takes maybe 5 minutes.

Now restart the tgt and tgtcharts GUI's. In the tgtcharts GUI, open up the LOOP CHARTS and look at the status of the target.

In the tgt GUI, go to the High Power Heaters for Loop 3. Reset the heater parameters to what they were before the reboot. In principle most of the parameters are automatically loaded and all you have to do is:
     (a) Verify all the heater settings.
     (b) DISABLE the Automatic PID Start
     (c) Change the Heater Mode to PID CONTROL MODE.

Watch the Loop charts, making sure that the target is stable.

Set the operations mode to RUN. Do this by,
(a) Select the Operation Mode option from the Security menu on the main tgt display.
(b) Click on the RUN option of the Operation Mode. In the alarm handler, the IOC opmode alarm should go off.

It is now safe to call MCC and ask for the beam to be restored.

	Hall C Target Operating Manual
Last updated 11/12/99 By Jörg Reinhold(reinhold@fiu.edu)