What should happen if an attempt is made to turn on both relays at the same time?
What if one relay is already on and an attempt is made to turn on the other relay? Is that allowed?
Hi,I have a pair of monostable Relays.I drive them with PCF8574 (i2c) and ULN2803 (see the circuit).The Problem ist... I need a hardware protection to disallow that both Relays are in the "switched state" (ON) at the same time.
Use an XOR function. (eg. 74LS86).
or to draw one in Ladder Logic... Relay2 Relay1 |+------[ ]-----------( )----+ | Relay1 Relay2 |+------[ ]-----------( )----+ | [ ] is a relay contact, and ( ) is a relay coil.If both were to be turned on at the same time, the first to engage would stay on. If relay 1 were on then relay 2 could not turn on, and vice versa...
Quote from: fungus on Jan 15, 2013, 10:42 amUse an XOR function. (eg. 74LS86).It works great for me, thanks!