19.10.2021
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