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DIOT reliability studies project
DIOT reliability studies project

Emc consultancy (ep ese)

Last edited by Volker Schramm
Page history

19.10.2021

Participants: G. Blanchot, G. Daniluk, C. Gentsos, V. Schramm

Slides

20211019_EMC_meeting_EP-ESE.pdf

Notes

  • Mentioned standards:
    • IEC 61000-4 series
    • CISPR 11 – Industrial equipment
    • CISPR 22 – IT systems
  • Most problems seen at CERN are for coupling of cables. Reasons are often incorrect connection, e.g. shields not connected on both ends.
  • No real EMC requirements do exist for CERN accelerator equipment.
  • Not only immunity, but emission testing is advisable too, regarding potential neighbouring systems (TBD)
  • DI/OT design feedback:
    • Flat cables (Ribbon; IDC) are a weak point. 1) They are very EMC sensitive and 2) they can generate noise, e.g. for fast IC signals. (Strongly) recommended to not use these cables
    • Shielding of cables as well as guide them alongside the chassis (GND)
    • Separate power and signal cables (rather use longer signal cables if needed)
    • Cables both inside and outside the DI/OT should be EMC tested
    • Treat COTS PSU as a component and check for EMC qualifications
    • Test RaToPUS for EMC
    • For peripheral boards, all is well covered on the front panel. Potential EMC risk identified may be for connecting cables, therefore: User cables are to be shielded & EMC guidelines respected
    • General PCB design guideline: uniform GND plane, don’t split on two planes
  • Various EMC equipment discussed:  We can get in touch with D. Valuch what they have
    • ESD probe (purchasing?)
    • Near-field probes for high-frequency electric and magnetic RF fields (purchasing?)
    • RF amplifier to inject common mode current
    • …
  • Different tests which should/can be performed (see also attachment):
    • Measuring conducted emissions on all cables + mains
    • Fast transients on mains
    • Voltage dips
  • “EMC responsibility” for peripheral boards should be on users
    • Provide information or guidelines (manual)
  • Laboratories for consultancy/testing:
    • Grenoble: AEMC
    • CH: Montena

Major Outcomes & Actions

  • Decide on overall EMC strategy. What is needed, when & where do we perform tests?
  • Get in touch with D. Valuch for available equipment and expertise
  • Define and perform RaToPUS EMC tests (if additionally needed to what is already done)
  • Crate redesign to reduce the amount of cabling (especially Ribbon cables) & shield remaining cables as well as guide them alongside the chassis; also separate power and signal cables