Re: Screened vs. unscreened cable
Amund, Open or connected screens? one theory states that the electric and magnetic field requirements are best served with opposing answers. However, we have found that when connecting a screen appears to cause a problem, it is worth persevering to track down the noise source and that keeping the screen connection is the best solution. Where dissimilar connectors are used at the ends of a cable, there may not be a problem with leaving one screen connected. With identical connectors, BNC for example, then leaving one screen disconnected can be difficult to maintain. There is no guarantee that the installation engineers, maintenance engineers or customer will ensure the unconnected end is always positioned at the correct end. We had a similar problem a little while ago where a product that had been in production for some years was to be connected to a new design. In this instance, the screen was also used as the 0 volt dc return and connecting this to ground at the new product introduced all manner of ground loops. To overcome this, and enable a standard screened cable to be used, the BNC connector at the new interface was insulated from ground. Capacitors were then fitted at the inlet between the BNC screen and ground. This allowed the dc return to go unhindered to the power supply while shorting any rf induced onto the screen to ground. Testing the cable with BCI showed good rejection of interference at levels way above the specification. Regards, Neil Helsby ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Grounding in an operating room environment ...
Anyone got the scoop on common grounding practices (either with equipment or with mains grounding) of operating rooms in hospitals here in the US and elsewhere in the world? Is the philosophy to ground everything or float everything with patient connected equipment? Can anyone point to any technical papers regarding ESD in an operating room? Anyone got any horror stories about ESD in the operating room that can be confirmed? Anything out there about ESD induced events in a patient during surgery or with anesthesia? Regards, Doug McKean --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Choce of Capacitance....
Using 1206 will force you to have (probably significantly) larger inductance than with 0805 or 0603. Inductance is the most important parameter above about a couple of MHz, because that will determine the decoupling impedance. Therefore you may decide to use all one value (except for the bulk caps) or to properly stagger the values of the caps (without creating parallel resonance, thus the values should not be far apart), but keep the inductance low. That criterion may force you to use smaller package than 1206. In addition, this will greatly depend on how you connect the caps, so keep low-inductance regardless of the cap size. Neven Hi all, I've just come from a discussion of decoupling capacitance In a nutshell, we have a combination of DSP and A-D/D-A conversion going on.. I have recommended that we use a single 4.7 microfarad 1210 packaged cap in place of the more traditional 0.1 and 0.001 microfarad 0805 caps in parallel. I believe that the data shows a better compromise favoring the single chip. Further, the need for BIG board entry caps is diminished. This is on an 8 layer board. Thoughts? Thanks, Derek Walton L F Research EMC Design and Test Facility --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: FCC Part15
It is not in the Part 15 rules. It is located in a public notice that is several years old now. Best bet is to contact the FCC OET in Columbia. John Shinn, P.E. -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Juhasz Sent: Friday, August 16, 2002 11:19 AM To: 'emc-p...@ieee.org' Subject: FCC Part15 Hi all, I am trying to find the section in FCC Part 15 that allows for the use of alternate testing (such as EN 55022 - Part 15 refers to CISPR 22). I've read it , but I can't seem to find the appropriate section. Do any of you know which section in Part 15 has this? Thanks. John A. Juhasz GE Interlogix Fiber Options Div. Bohemia, NY --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
FCC Part15
Hi all, I am trying to find the section in FCC Part 15 that allows for the use of alternate testing (such as EN 55022 - Part 15 refers to CISPR 22). I've read it , but I can't seem to find the appropriate section. Do any of you know which section in Part 15 has this? Thanks. John A. Juhasz GE Interlogix Fiber Options Div. Bohemia, NY --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: EMC - SLIM
Amund and everyone Nothing has happened for the last 12 months. There is a meeting of the EMC Working Party on 5 September 2002, but this discusses other matters as well as SLIM. The item on the agenda relating to SLIM is to receive a status report. There does not appear to have been a new draft for discussion produced. I will keep everyone informed of any progress, once the outcome of the WP meeting is known. Best wishes Brian Jones EMC Consultant and Competent Body Signatory - Original Message - From: am...@westin-emission.no To: IEEE / News Group emc-p...@majordomo.ieee.org Sent: Friday, August 16, 2002 1:40 PM Subject: EMC - SLIM Hi all, Have there been any progress in the EMC SLIM process lately ? any news ? 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Just how many to test...???
My opinion is based upon an assumption - the product is intended to be operated from a mains connected power source. I would test it with the power sources that would optionally be provided with the product and test the system at 120V and 230V. Richard Woods Sensormatic Electronics Tyco International -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, August 15, 2002 11:08 PM To: lfresea...@aol.com; emc-p...@ieee.org Subject: Re: Just how many to test...??? I don't know what EN 61236 is, this answer applies to the standard CE/RE testing that is always applicable to all kinds of equipment. One response to this query seemed to assume that the 24 Volt model was dc. I assume it is 24 Vac, because that is a common household control voltage, and because the only difference in each model is the transformer. I'm not up on the legalities, but I would say that your differential mode emissions will be maximized using the low voltage model, since the current draw will be greatest. Common mode emissions will be greatest with the 230 Vac model, because the potential applied to stray capacities is the greatest. The 120 Volt model is intermediate for both kinds of conducted emissions. If both high and low voltage models meet requirements, then I would expect the intermediate voltage model to also meet requirements. -- From: lfresea...@aol.com To: emc-p...@ieee.org Subject: Just how many to test...??? List-Post: emc-pstc@listserv.ieee.org Date: Thu, Aug 15, 2002, 2:26 PM Hi all, I've been approached and asked to advise on just how much to test... remember I'm a test lab so my answers may be biased. My client has three designs, the only difference is the transformer. A 24 V version for low voltage control systems ( about 49.5% sales volume ) A 120 V version for use in the USA, but will have the CE mark. ( about 49.5 sales volume ) A 230 V version destined for the EU. ( about 1% sales volume ) He is testing to EN 61326, and asked me if he should test all three, or can he reduce the testing based on volumes of the products sold. I suggested that the 24 volt version be tested period... The 120 volt version tested period. And the power input portion of the 240 volt version be tested. Anyone in the group want to comment? Thanks, Derek Walton L. F. Research EMC Design and Test Facility.
repetitive stress
We are developing a hand operated mechanical device. I am looking for regulations or guidelines which manufacturers must comply with to show due diligence with designs in avoiding repetitive stress related issues. Richard Woods Sensormatic Electronics Tyco International --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Screened vs. unscreened cable
Assume two separate units which is connected to each other via a screened cable. What happens if we remove the screen connection in one of the units ? will the cable function as an unscreened ? Amund --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
translation
Using auto-translation programs can be interesting. FreeTranslation seems ok but using it to try English to German and then back to English gives: Attention class 2 laser irradiations if opening. Stiff you in beam not. Regards, Neil Helsby ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Books / EMC in Installations - Thanks
Thanks all, I'll go for EMC for Systems and Installations (Tim Williams Keith Armstrong). Amund --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Just how many to test...???
I don't know what EN 61236 is, this answer applies to the standard CE/RE testing that is always applicable to all kinds of equipment. One response to this query seemed to assume that the 24 Volt model was dc. I assume it is 24 Vac, because that is a common household control voltage, and because the only difference in each model is the transformer. I'm not up on the legalities, but I would say that your differential mode emissions will be maximized using the low voltage model, since the current draw will be greatest. Common mode emissions will be greatest with the 230 Vac model, because the potential applied to stray capacities is the greatest. The 120 Volt model is intermediate for both kinds of conducted emissions. If both high and low voltage models meet requirements, then I would expect the intermediate voltage model to also meet requirements. -- From: lfresea...@aol.com To: emc-p...@ieee.org Subject: Just how many to test...??? List-Post: emc-pstc@listserv.ieee.org Date: Thu, Aug 15, 2002, 2:26 PM Hi all, I've been approached and asked to advise on just how much to test... remember I'm a test lab so my answers may be biased. My client has three designs, the only difference is the transformer. A 24 V version for low voltage control systems ( about 49.5% sales volume ) A 120 V version for use in the USA, but will have the CE mark. ( about 49.5 sales volume ) A 230 V version destined for the EU. ( about 1% sales volume ) He is testing to EN 61326, and asked me if he should test all three, or can he reduce the testing based on volumes of the products sold. I suggested that the 24 volt version be tested period... The 120 volt version tested period. And the power input portion of the 240 volt version be tested. Anyone in the group want to comment? Thanks, Derek Walton L. F. Research EMC Design and Test Facility.
