Ray - You asked about info on interlock switches and relays. Switches I am not familiar with - but a special type relay is often required for interlocks on safety gates for machine tools, robots, presses, etc. - don't know about your instrument. The German machine tool assoc has a standard ZH1/457 which requires "forcibly guided contacts" maintaining at least 0.5mm gap over life. No contact may change state out of syncronization with another even in the event of welding, coil failure, etc.. Both Siemens and Hengstler in Germany make such a device. I am not aware of a US mfr.. If interested, you may contact me for a Siemens datasheet. They are not in the same Siemens group we are, but I can provide contacts at either company if you are interested.
Best regards, Harold Leipold Siemens EC Princeton, IN Tel. (812)386-2161 Fax. (812)386-2616 E-mail [email protected] ---------- From: Ray Russell To: emc-pstc Subject: Interlocks List-Post: [email protected] Date: Friday, September 20, 1996 9:24AM Dear Friends, I've received some contradicting information in relation to the need for interlocks, and would like to bring it up to the group for discussion. We have an instrument that has a removable side panel. A tool is required to remove the panel and there is hazardous voltages behind the panel. The user is instructed to remove the panel for installing options, and maintenance. Opinion 1 - Access is restricted by a tool, so no interlock is required. EN61010-1 sec 6.1.1 states: The following Hazardous live parts are permitted to be accessible to the operator during normal use: - parts intended to be replaced by the operator (e.g. batteries) and which may be Hazardous live during the replacement or other operator action, but only if they are accessible only by means of a tool and have a warning marking.. Opinion 2 - When an operator is instructed to remove the panel, an interlock is required. An agency told me that once an operator is instructed to remove a panel, it is treated as if no tool was required to remove it. Also, if anyone has information on high integrity components, such as interlock switches and relays, I would appreciate some information. Thank you for your thoughts. Ray [email protected]
