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GlueX Electronics Review Jefferson Lab July 23-24, 2003 R. Chris Cuevas Jefferson Lab Physics Division Group Leader -- Fast Electronics. Topics: Printed Circuit Board Manufacturing Maintenance Power & Grounding. PCB Manufacturing.
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GlueX Electronics Review Jefferson Lab July 23-24, 2003 R. Chris Cuevas Jefferson Lab Physics Division Group Leader -- Fast Electronics Topics: Printed Circuit Board Manufacturing Maintenance Power & Grounding GlueX Electronics Review --R.C. Cuevas
PCB Manufacturing • JLAB Electronics Group & GlueX collaborators have extensive experience with design and ordering PCBs in industry. • PCB is not a mechanical part! • Electrical characteristics more important than mechanical tolerances • Design Tools are essential for verification • We have PCAD, Gerber View Tools but,,, • More extensive simulation tools would be useful • (e.g.) PCB layout simulation, signal integrity modeling GlueX Electronics Review --R.C. Cuevas
PCB Manufacturing • 1000’s of custom PCBs have been manufactured in industry for CLAS. [Drift Chamber, Level II Trigger, Timing distribution] • Typical PCB development ‘procedure’ • Design requirements -- Specifications/Format • EECAD -- Schematic capture -- Board layout • Prototype ordered -- Assembled on site • TEST -- Verify circuit performance -- Record results • Capture all ECOs [ Engineering Change Order ] GlueX Electronics Review --R.C. Cuevas
PCB Manufacturing • ‘Procedure continued’ • Verify all ECOs in new layout • Prepare order for contract manufacturing & assembly • Evaluate manufacturers -- Not on price alone! • Long term reputation/experience • Documented Quality Control standards [ IPC,ISO ] • Automated assembly equipment • Bare board test equipment • 1st Article assembly very important GlueX Electronics Review --R.C. Cuevas
Maintenance • No glamour, but planning NOW is critical for high availability • Must plan for spare PCBs for each custom design • Crucial components must be identified • Spare devices purchased for long term replacement • DOCUMENTATION -- Must archive and provide on-line • Schematics • System/Wiring Diagrams • Maintain Firmware Development Tools and Code • Test Programs GlueX Electronics Review --R.C. Cuevas
Maintenance • High Availability Demands: • Low Mean-Time-to-Repair • Example: Powered Card Enclosures [ “Crate” ] • Removable power supply units • Removable fan tray • Easy access to circuit boards -- test points • Remote monitoring of “Crate” systems -- V, I, Temperature • Remote reset feature where applicable GlueX Electronics Review --R.C. Cuevas
Maintenance • Planning for the repair “shop”: • Must provide training for technicians on new designs • Test “Stations” for all custom and commercial boards • Ability to repair/rework circuit cards, power supplies • Assure proper tools and test equipment are provided • Establish circuit board calibration/repair/tracking database • Use new technologies for keeping track of all modules in the experiment. [ RF Id,, Bar code ] GlueX Electronics Review --R.C. Cuevas
Power & Grounding • Very extensive topic and, • We have good experience with Hall B [ CLAS ] • Careful planning of power isolation and grounding grid • Extensive review of AC Mains requirements • Must include grounding grid requirements for Accelerator connection and civil engineering • Must identify all large “consumers” of AC Mains • Superconducting Magnet system • Building utilities [ HVAC, LCW, Pumps, Crane ] • Front End Readout crates • High Voltage systems GlueX Electronics Review --R.C. Cuevas
Power & Grounding GlueX Electronics Review --R.C. Cuevas
Power & Grounding • Reasons for Grounding • Shock and Safety Hazard Control • Reduce lightning related gradients • Avoid injury to personnel • Avoid damage to Electrical/Electronic equipment • Establish return reference • EMI control • Shield reference for cables, isolation transformers GlueX Electronics Review --R.C. Cuevas
Power & Grounding • Learn from omissions: [ CLAS example ] • Plan for dedicated network conduit(s) • High speed network gear & beam-line diagnostic • equipment not in close proximity to detector power supplies • Low radiation levels in Hall D • Should allow extensive use of Fiber Optics for • Communication links -- • Data acquisition -- • Optical isolation for control circuits where applicable GlueX Electronics Review --R.C. Cuevas
Summary • PCB Manufacturing • Excellent design record. • Almost zero problems with production PCBs in CLAS • New design/verification tools would be beneficial • Maintenance • Electronics Group is a small [ efficient ] group • Large portion of readout electronics for CLAS and other Halls are mostly commercial [aging] electronics • Custom electronics will demand better tracking, repair and long term availability of crucial components • Power & Grounding • Careful review of AC Mains requirements NOW • Requirements for detector power supplies, HV, Front End crates need to be established,,, • Grounding/shielding configuration is crucial for low noise measurements and reducing EMI pickup GlueX Electronics Review --R.C. Cuevas