EMC Instructions for Power Outages
Contents:
- Preparation for announced outage ('Brownout')
- When power has been lost ('Blackout')
- When power has been restored
Preparation for an Announced Power Outage
Brownouts usually do not affect IR2 power, but only the accelerator and PEP2
infrastructure. Therefore no particular action is required for the EMC.
In the case that IR2 power will be affected,
the following steps can be taken:
Unless data is still being taken the EMC frontends can be turned off
(this is not a critical measure, i.e. optional):
In the Electronics Hut, press the only button on the 100 LV
power supplies located in
racks B2603-01/2/3.
This will remove the primary heat source and give the water chiller a chance to
cool the end flanges before the outage occurs, avoiding some crystal temperature
alarms.
What to do in Case of a Power Outage
In the Electronics Hut, turn off the 100 LV
power supplies located in
racks B2603-01/2/3. by pressing the button on each front panel.
The idea here is that when power comes back you want to be sure the chillers are
running properly before the frontend is powered up. Normally the LV power supplies
are interlocked, i.e. turned off automatically in case of a chiller problem.
However, in a prolonged outage we could lose power to both chillers and the
interlock SIAMs (the SIAMs are on UPS, but eventually the batteries run out).
You want to be in full control when power comes back and avoid accidents
due to a SIAM being in a wrong state, unlikely as it may be..
Recovering after a Power Outage
In the order listed here,
- Convince yourself that all EMC chillers are running properly (fluorinert
and water chiller). They should have temperatures and flowrate as posted
next to the LED displays on the chillers. The fluorinert chillers should
each have four green LEDs lit.
For any problems with the EMC chillers contact an expert:
- the EMC commissioner (see whiteboard for commissioner on duty)
- any EMC run contact
- Bill Wisniewski (p. 849-9661)
- Eric Doyle (x2861)
- Check if the diode bias power supply (
red CAEN crate
in E-Hut rack B2603-03) has turned on properly. The LCD display should show 'CAEN SY527'.
If not, turn the key to 'off' and back to 'on' position. The crate
takes a few minutes to boot. If it does not boot properly, press the black
RESET button on the red communications module in the EMC-ILK crate
(rack to the right of bias supply, top crate).
- If UPS batteries have run out: Switch on the two VME crates
housing the monitoring (EMC-MON)
and interlock (EMC-ILK)
IOCs in the top of
rack B2603-04.
It may take the IOCs a few minutes to reboot. They boot off bbr-srv01, i.e.
if this machine needs to be online first.
Check if the monitoring (EMC-MON) and interlock (EMC-ILK)
IOCs are working properly: can you bring up the EMC EPICS panel
and is everything non-white? If not, consult the
Monitoring Troubleshooting Page.
- From the EMC EPICS panel, click on 'Bias Voltage' and push the green
button on the bottom of the panel that appears. You should see all 10
channels ramp up. After a minute, all channels should have settled into
their green values for 'Vmon' and 'Imon'. If there is no variation in any
of the numbers over more than 30sec the communication to the power supply
has broken down. Press reset button on communications module as described
above.
- Turn on the frontend electronics:
In the Electronics Hut, switch on the 10 crates
housing the 100 LV power supplies located in
racks B2603-01/2/3.
The switch is located on the lower left part of the crate (it may
already be in the 'on' position, pointing upwards.
Then switch on the power supplies by pressing the only button on
each front panel.
All power supplies should have their green LED lit
[picture].
- The EMC EPICS panel should have no alarms left. Before taking data the
system should be tested with a lightpulser run (central calibration).
Ivo Eschrich
- Valid until modified.
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![[picture]](/BFROOT/www/Detector/Calorimeter/Operations/pics/LV_Bwd1.jpg){kind=link}