Transcript Status of Rod Production at UCSB

Status of Rod Production at UCSB
This report covers the last week
Reporting for:
assembly
testing
14 June 2005
C. Campagnari (UCSB)
Dan Callahan
Susanne Kyre
Stephen Jaditz
Puneeth Kalavase
Jim Lamb
1
Tests of I2C errors
• Visit from Guido Magazzu & Wim Beaumont June
3 to June 7
– Following the visit at FNAL
• Report available
– http://hep.ucsb.edu/cms/rod/I2c_230_investigation_v.1.2.doc
• To make a long story short, problem is due to
different RC on I2C clock lines going to hybrid and
optohybrid
– Causes wavefronts to change at slightly different times
– See http://hep.ucsb.edu/cms/rod/TheGreatI2CMysteryv2.ppt
14 June 2005
C. Campagnari (UCSB)
2
Present Electrical circuit
FE-Hybrid
82W
Parasitic on FE Hybrid CH
SCL
SDA
CH > CA
14 June 2005
AOH
Parasitic on AOH CA
82W
C. Campagnari (UCSB)
3
(Main) Solutions under investigation
• R=82 Ohms  R=0 Ohms
– As implication for power-on sequence.
– Would need to power-on control and F.E. at
the same time
– Most robust from I2C stand point
• Tune one of the R to equalize RC
– R to AOH ~ 820 ohm
• Jumper across resistance (see picture
next page)
– Forces same RC
14 June 2005
C. Campagnari (UCSB)
4
Solution 6
FE-Hybrid
82W
Parasitic on FE Hybrid CH
SCL
SDA
AOH
Parasitic on AOH CA
82W
PSU
PSU
Control before FE
14 June 2005
C. Campagnari (UCSB)
5
Tests at UCSB
Rod
192
Mod
jumper
Errors
no i2c errors (warm, cold cycle)
(some header errors)
361
498
498
R=820 ohm no errors (warm, cold cycle)
no errors (warm, cold cycle)
R=0
R=0 single PS no errors (warm, cold cycle)
noise OK
20
14 June 2005
R=3 kOhm
error "23" in Wim's i2ctest.sh
C. Campagnari (UCSB)
6
Other stuff
• Still fighting coolant leak
• Isolated to flowmeters inside fridge
• Catalog says: flowmeters have vitan o-rings
– Vitan is "bad" with C6F14
• Took it apart, observed damaged o-rings
Solving this is highest priority to be able to begin
production when I2C business is settled
14 June 2005
C. Campagnari (UCSB)
7