Dennis: Take a look at the 12HV615. Kind Regards Bill -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Dennis Crawley Sent: Wednesday, April 16, 2008 6:54 AM To: Microcontroller discussion list - Public. Subject: [EE] SR latch for 24VDC Hi fellows, I'm trying to desing a very simple SR circuit to control two 24VDC signals coming from two CAMs inductive sensors) and one 24VDC output which is connected to a PLC input. (noisy machine) In most of the desings I've ended up with this (block) configuration opto--\ logic--opto opto--/ | | source (taken from PLC) For the logic part I used a 555 with reset and trigger tied to positive through 100K resistor. Since the 555 used 18V max,... I have calculated a 18v1w zener with a 100ohm1/2W resistor limitation to power the kit. I've also thought about a 12F, but I don't want a DC-DC converter,... unless it would be the best and safer way to do this task. True table S R Out REdge x 1 x Redge 0 Is there any chip out there that works over 24VDC directly? Should I have to desing this with Op amp? The challenge is to desing the SR on the 24VDC rail, with the less number of componentes as possible. I'll appreciate any hint . Cheers regards. Dennis (lurker) -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist