plc_heaven
Member
Hi. I'm a newbie to PLC's. I need to control a lamp from two separate switches - much like two three-way switches would control a light in the hallway of your house. Any help would be greatly appreciated. Thanks.
So
_ _ _
A + B = C //Both switches down - light is off.
_
A + B = C //Both switches up - light is off.
_
A + B = C //A switch down, B switch up - light is ON
_
A + B = C //A switch up, B switch down - light is ON.
We can make a truth table now:
A | B | C
0 | 0 | 0
0 | 1 | 1
1 | 0 | 1
1 | 1 | 0
Looks like a way to get a new engineering manager trained!Alaric said:Admitedly, it would be much easier to just draw the ladder for the answer, but then our PLC newbie would not learn.