Well, this might be the reality in a case I have been introduced to lately.
Case: A company are manufacturing PowerLine Communication products. They communicate via the power lines and a typical link is between a consumer residence and the nearest power station. The products can of course also communicate inside the consumers residence. The communication protocol is called CEBus http://www.cebus.org/which and make use of the frequency band 100kHz-400kHz and the amplitude is approximate 2-5V. A typical length of a transmission is 25ms and occurs approximate one time pr hour. First of all, AFAIK PowerLine Communication and PowerLine Transmission (broadband 1.6MHz-30MHz) are now coming will full force in EU and CENELEC/ETSI are working together regulate this type of transmission path and also coming up with standards. The problem for the manufacturer is the conducted emission requirements in EU. According to the EN55022B levels the maximum quasi-peak emission is 66dBuV@150kHz, and a typical PLC (under transmission) which has been measured, showed the value of 120dBuV (peak). With no transmission it had a margin of 10dB (quasi-peak) and 30dB (average). The radiated emission had a margin of 10dB. Well, conducted emission is the problem when transmitting. But, as I said, the transmission occurs only 25ms/hour. The national authority will not allowed this product to be placed into the marked because it do not fulfil the EN55022B limits (100kHz-400kHz) under transmission mode. No way. Other national authorities have other approaches on this case, they say " as long as you do not disturb other equipment, install it. If you do disturb, we will come and remove it". They also say " install it even if it does not fulfil EN550022B, but we will remove it if it disturb others". Two completely different approaches as you see. Questions: 1. Is it possible to have different approaches within EU ? 2. Since PLC/PLT is "quite new" technology and since we do not have any EU product standard (no standard for whose who are using 100kHz-400kHz band), I like the approach "as long as you do not disturb other equipment, install it. If you do disturb, we will come and remove it". What is your opinion about this? 3. The transmission occurs very seldom. 25ms/hour, that is 7e-6 and approximate 0,001% transmission rate. Can this seldom transmission rate be an argument to not test the PLC product under continuous transmission ? I would say yes, but which rate is acceptable / reasonable ? So, why should the company close down ? Because if the national authority gets what they want, there will be one sale. Logical, but is it a correct prohibition the authority call? Best regards Amund Westin, Oslo/Norway ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
