1. LV-workshop during CMS Electronics week
During a recent Workshop, Sergei Lusin reported that in CMS was observed an OVERHEATING IN SEVERAL POWER CONNECTORS.
This is a potential “Fire hazard” that affect all Subdetectors using Power Supplys which use the 55A “powerclaw contact”
Specifically the CAEN A3486 – (MAO)
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2. Short and Long term suggestion plans
It was generally agreed upon that something needed to be done
to allow long term lifetime of the system.
Short term plan
Use softer cables less capable of transferring twist,
(which does not involve extensive recabling)
Followed by the addition of a screwed bracket.
Option
Voltage drop measurement between MAO and Easy Crates by installation of sense wires.
( The option will be tested by the HCAL)
Long term plan
The ultimate solution will require the modification of
the connector assemblies on the power supplies, which
will involve discussions with the vendor, and the
development of a retrofit plan.
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3. Partial recabling on PIXELs racks X2F36/X2F37
Power Supplies cables replacement made at P5 (17February2010)
Following the “Short term solution” we decided the replacement of the short cables links between the AC-DC Converters (MAOs) and the Easy crates 4000, using more flexible cables.
More in details for each racks we introduced two new short extensions related to the upper MAO, and we replaced three other extensions related to others MAOs.
This will allow the spring mechanism inside the connectors shells to align the contacts properly.
Again, to prevent any progressive “walking – out” of the plug connectors
we added a screwed bracket between the cable connectors and the panel.
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4. LV- workshop during CMS electronics week
General discussion & answers
Do you have in-line fuses on the service Power Connections
that are fed directly by MAOs? YES
Have you observed any strange turn-off issues of the DC outputs
In the event of interruption of primary or service power? ANY
How do you fix bad modules (LV, HV, any others) ? Via a Pixels support
activities performed at TIF, & via CERN pool.
How do you keep records? Via elogs- etc.
Remarks: To control all the devices used at P5 has been created a link on TWIKI
twiki.cern.ch/twiki/bin/view/CMS/PixelCaenSpareComponents
with an UPDATE MAP of the Power System Parts installed.
You can find also a MAP of the DEVICES out of the system......(spare parts)
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5. LV- workshop during CMS electronics week
General discussion & answers
What hardware interlocks do you use on the LV and HV Systems?
Built –in caen system
According to our request a new firmware for the A4603 has been
implemented, so now the HV can ramp down to V0 using a signal
generated by the LHC and sent by the BRM directly to the
Pixel CAEN system ( V sel input ) The LV is unaffected.
Who’s in charge of keeping the LV & HV systems working?
Gino Bolla, Mauro Dinardo, Pasquale D’Angelo, Bill Gabella, Lalith Pereira
And the interface with DCS? (CAEN system, and Branch drivers)
Gino Bolla, Mauro Dinardo, Pasquale D’Angelo, Bill Gabella, Lalith Pereira.
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6. Quickly test the devices malfunctioned.
PIXELS SUPPORT ACTIVITIES PERFORMED AT TIF
In addition to the PILOT DETECTOR,
an improved TEST FACILITY can perform varius technical functions.
Here the most important: 1)
Control all the spare devices ,and make sure they are ready for replacement. 2)
Quickly test the devices malfunctioned. 3)
Long term test on devices with suspected faults. 4)
Test the functionality of the new Firmwares. 5)
Run all the functional test on prototypes devices for next CMS-UPGRADE. 6)
Activete a very simple set-up (with Panel + Adapter Board + Flex Cable + Port Card + Aoh) on which we can easily operate, to try to understand and address problems, in attempt to avoid future occurences. 7)
Help to maintain under control all the PIXELS devices used at P5.
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7. IMPROVEMENTS ON THE.......... Power Supplys Test Facility Setup
Same configuration used at P5
A3486 MAO
A3486 (mao)
Dummy loads
MSC-long cables (43m)
Spare crates & modules
Modules under test
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8. BUS CONNECTIONS
The A1676 Branch Controller handles a chain
wich includes both: EASY crate and A3486 (MAO)
A3486 (MAO)
(INPUT connector)
A3486 (MAO)
(INPUT connector)
2x2KW/1x4KW 48Vdc Power source
A1676 Branch Controller
(OUTPUT connector)
Easy crate panel
(INPUT connector)
Mainframe
Easy crate overview
Branch Controller overview
The crate, which is suitable to host
P.S. Modules A4602 & A4603
is handled by one of six branches
of the A1676 Branch Controller.
The Branch Controller must be linked
to the EASY crate usually placed
in the “ostile area”
The A1676A is the interface between
the Mainframe and the remote boards
in the Easy crate.
The channels of the Easy boards
will operate as channels of the A1676A.
Up to six Easy crates can be controlled
by one A1676A.
The crate panel is provided with
I/O flat connectors of the Easy Bus
Remote control and the 48V Status
Input connector, wich allow the
PS boards microcontrollers to detect
failures in supply voltages and
consequently to enable PS channels
ramping down.
Easy crate
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9. CAEN devices – Firmwares overview
Firmware Version
Issued on
Currently used at P5
Nov
Jul
May 2008
Dec. 2007
Power Supply
A4603
Power Supply
A4602
May
Jan. 2008
May
Dec. 2007
Apr. 2007
48 Vdc Converter
(MAO)-A3486
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10. CAEN devices – Firmwares overview
Firmware Version
Issued on
Currently used at P5
Nov
Mar
Feb
Jan
Dec
Sep
Jul
Jul
Feb
Mainframe
SY1527
Dec
Nov. 2008
Jun
May
Sep
Jul
Branch Controller
A1676A
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11. New features of the FIRMWARES used by PIXEL Communities
Branch Controller
A1676A
In the new Firmware (rel. 3.01) the Vsel bug has now been corrected
Bug fixed : Internal memory corruption caused by the use of the Vsel parameters.
Power Supply
A4603
According to our request with the new Firmware (rel. 1.04) the H.V.
can ramp down to V0. The L.V. unaffected
As a result of these new features will be possible use a signal generated by the LHC and sent by the BRM
directly to the pixel caen system ( Vsel input )
The A4603s will then ramp down from V1 to V The A4603 L.V. Is unaffected.
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12. Simple and Easy TEST STAND act to understand and address problems.
We can use the same TEST FACILITY
used for the PILOT DETECTOR
Test Stand details
Port card + CCU + AOH
Panel + Adapter Board + Flet cable
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13. CMS – Pixels DEVICES
To control all the DEVICES used at P5 has been created a link on TWIKI
Where you can find an UPDATE MAP of the Power System Parts installed.
You can find also a MAP of the DEVICES Out of the System.…( Spare Parts.)
twiki.cern.ch/twiki/bin/view/CMS/PixelCaenSpareComponents
Our idea is to improve this very useful tool, extending it to other devices
…( FED…FEC…etc. )
and adding a history of any inconvenient occurred on that device.
This would help us to TRACE the history of the Channel.…Layer….Sector.
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14. SUSPECTED MALFUNCTIONS…………….._
Sometimes happens that a power unit ( A4602, A4603 ) goes bad, so suspecting
that the module has problems, we replace it. _
The swapping process fixes the problems, but the replaced unit ….tested at TIF…. is OK _
So the problem is solved but still…… we don’t know why. _
We had several technical interview with CAEN Engineers to understand in detail how the modules works.
HERE ARE THE ANSWER.
The Firmware for A 4602 and A4603 are stored in a flash Eeprom inside a Micro Controllers which handled the module.
There is NO “Firmware Load” at Power ON.
Therefore a corruption of the Firmware can NOT be recovered by a Power Cycle.
Each time a module is removed and re-inserted into the crate,( which is equivalent to power cycle the crate ) there is an integrity check of the Firmware.
If the integrity check is not passed, then the module can no longer be accessed, and the Firmware must be reloaded into the Eeprom.
The RESET button on the front panel acts directly on the microcontroller, and perform
a reset of all channel for that module.
Through Telnet can be performed a so called HW Reset, which will Reset all the modules in one crate.
The Recovery-command through Telnet, resets only the communication. The channels remain on.
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15. Summary Here are been mentioned the most important
All the activities currently being held at TIF
play a support function mainly for the
PIXEL COMMUNITY
Here are been mentioned the most important
Others activities will arise in the light of the
coming CMS - UPGRADE
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16. FINAL REMARKS and CONCLUSION
For what concern pixels ( Barrel & Forward ) we can said :
- The Power Supply failure rates is extremely low.
Are already several months that we don’t observe failure
on our devices.
My personal opinion:
This very high efficiency is mainly due to the big effort of everybody
done during the commisioning, and the preliminary test made in the past.
And also thanks to the “CONSTANT & PERMANENT
Pixels support activities performed at TIF.
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