Great idea - - However the whole purpose of equipment designed for - "Electrical Equipment for Measurement, Control & Laboratory use ...." is to measure & control. This can be most difficult to do if your sensors and control points are forced to be located in the "building". In the case of some of my company's products you most definitely want the process away from the building, unless you enjoy the smell of sewer lines & treatment plants". We, as a mater of policy, surge all lines over 3 meters in length. We have found by sad experience that failing to do so invites customer field "problems" and warranty issues. By hardening our I/O circuits we ensure correct operation of our products even when our customers place one of our sensors / devices next to a (several) hundred HP motor. In my opinion, We should be testing to the realistic conditions our products will encounter in the real world. By doing so, my company has lowered customer complaints and warranty issues to the lowest in our industry segment. A dollar saved in warranty is a dollar earned in profit. The net result of this is my company is healthy and I have a reasonable expectation of continued employment up to retirement (only 8 more years - yeaah). Best regards to all for a great holliday season. Michael Taylor - NCE Principal EMC Engineer Hach / American Sigma divisions Danaher Corp.
-----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Wednesday, December 20, 2000 2:37 PM To: [email protected] Subject: LMC With Regard To Surge Test Cable Length EN 61326-1 Product Family, Laboratory, measurement, and control equipment within the scope of EN 61326-1 does not require surge testing until reaching the definition of Long Lines (see clause 3.6) which is NOT 10 meters, but does include lines that can leave the building. This is an important point. By instructing the user to not wire the interface outside of a building and limiting the maximum cable length, surge testing can be dropped from your test plans. Even better, it also encourages the customer to seek a better solution to connecting buildings. Copper based networks or industrial I/O busses should avoid being routed outdoors in favor of a media converter allowing the use of a purely fibre optic cable. This dramatically reduces the threat of a lightning induced RF field, plus yields other odd benefits such as elimination of ground loop potentials. Proponents of trying to meet the surge requirement on copper interfaces are encouraging the use of copper wiring between buildings which, in my opinion, is risk to both connected equipment and anybody in contact with the equipment at the moment a surge (or direct strike) occurs. Best Regards, Eric Lifsey Compliance Manager, National Instruments USA 512-683-8474, Fax 512-683-8880 ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
