On Wednesday 21 June 2017 15:03:23 kqt4a...@gmail.com wrote: > I am just a tinkerer so I'm looking for advice. I have a project using > an ESP8266 to control a light. I am using a Panasonic AQY280EH to > switch the light. What is the safe protocol for mounting and > connecting a device that is using a high voltage.
One normally uses an opto-isolator to separate the computer from the high voltages in the external world. Wire the + terminal of the led in the isolator, with a current limiting resistor to a 5 volt supply, and wire the - terminal of the led to the control output. You want to "pull" the - terminal to a logic zero to turn on the led because thats the more capable direction in terms of the current needed to turn on the led. The other 2 terminals of the isolator are connected, aka "on" when the led shines on the other side, with a high voltage, usually up to 5,000 volts, of isolation, between the two parts of the isolator. And generally, when the led is energized, the circuit on the other side of the air gap will be too. The output side may or may not be polarity sensitive, and if it is, will also have + and - markings. You can get ready made kits for 1 or 4 on a board, of such devices from ebay for quite nominal prices. I just wired up one channel of a 4 channel I had in the spares drawer, to pull the RST terminal of the VFD running my lathes spindle down to its control ground so I didn't have to get a step-stool to reset it by hand in the event it faults. A .4 second reset pulse sent by the pi running things works fine. Those generally are made for various input and output voltages, so you buy them accordingly. This one expects a 5 volt input, and controls the 12 volt swing inputs of the VFD. The VFD supplies the 12 volts needed, as well as its local ground/common. Unfortunately, those are common on this particular kit so I can't use it as 4 independent output channels. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
