RE: EN55013 (2).
Kaan, I developed and proposed flow chart - Decision tree for peak detector measurements, at least six years ago at U.S. National Committee for IEC TAG for CISPR SC G. I presented the same document later that year in Berlin to CISPR SC A and SC G on behalf of U.S. National Committees. Proposal has been approved with minor modifications suggested by Israel and Japan National Committees. It is published as CISPR Publication 22:1997 Annex B (normative), page 85 and will be propagated as applicable throughout other CISPR publications. Intention of that document was to formalize rather common practice to use peak instead of quasi peak or average detector for conducted disturbance measurements at 150 kHz to 30 MHz. Use of peak detector speed up the measurement process. If product fail the test by using peak detector, there would be still a chance to pass the test by using prescribed QP or AVG detectors. Document allows use of peak detector instead of QP and AVG and QP instead of AVG. It does not mandate it. In a case of dispute, precedence results are with prescribed QP and AVG detectors. Document did not affect limits. Mirko Matejic The Foxboro Company
EN55013 (2).
Hello Group, I presented a question to the group regarding EN55013 Clauses 3.2 and 3.5. and the application of the quasi-peak or average test methods and I receive the following response: You must make a Quasi-Peak measurement. Provided this measurement is below both QP and Average limits you do not have to make an average measurement. If it is not below the average limit you will also need to make an average measurement and compare that to the average limit. The reason for this is that the average reading will never be higher than the QP measurement. The standard is trying to save you time by not having you make unnecessary measurements. The clause only applies to conducted emission measurements. Having said that I notice that disturbance power has QP and average limits. Although not stated in the standard you could still apply the same rationale to disturbance power measurements. If the QP reading is below the average limit there is no need for Average measurements since they will also be below the limit. I understand that Clause 3.2 requires conducted measurements to be verified with the average measurement method (possibly because the low frequencies have long on and off durations which could affect quasi-peak measurements?). I question however, whether a requirement in one clause (3.2) can or should be applied to another clause (3.5) when the limits for quasi-peak measurement are clearly defined in Clause 3.5 with no reference to the paragraph in 3.2 regarding the concern for average measurement verification. In other words, do I believe in and interpret the standard as it is written, or not? I would like to take the position that the committee that produced the EN55013 standard wrote Clauses 3.2 and 3.5 the way that they are for reasons that (apparently) are not common knowledge. Perhaps this issue has been or is being addressed in the EN55013 technical committees and I was hoping that someone from the committees could shed some light on this matter. I am prepared to accept the application of the average measurement paragraph in Clause 3.2 to Clause 3.5 as long as an official source declares this as an appropriate deviation to what the standard presently says and indicates that EN55013 is being changed to reflect this understanding. My reason for asking this question is to clear up the confusion in my mind regarding this issue... and maybe we can all learn something in the process. I also like to see standards that say what they mean and mean what they say - at least as much as is practicable... (I know I am dreaming, but I've got to try!) Kaan L. Gregersen
