| ??? 07/24/04 22:50 Read: times |
#74811 - RE: Reed Switch Sensor Responding to: ???'s previous message |
I said:
Why do you need additional opto isolation with reed relays - they inherently provide galvanic isolation! Kai Klaas said:
Nevertheless, in some applications it can make sense very well to keep the +5V of microcontroller and the supply voltage of relays separated by a galvanic isolation. HE said he has "reed relay inputs." I take this to mean that he is using the reed relays in his design - on his PCB - to provide the isolation: the relay contacts connect to the processor, and the coil connects to the input signal. See: http://www.8052.com/forum/read.phtml?id=74786 In this case, the relay supply is galvanically isolated from the microcontroller supply - so an opto-isolator is superfluous. However, I am now getting the impression that the reed relays are actually in the external equipment: http://www.8052.com/forum/read.phtml?id=74808 So, the fact that they are reed relays is irrelevant to his design - all that matters to his design is that it's an open/close switch contact. In this case, I agree that an opto-isolator could be worthwhile. |
