Siemens Simatic S7 Series Manual page 37

AND Operation. Each.rung.or.network.on.a.ladder.represents.a.logic.operation..
The.following.programming.example.demonstrates.an.AND
operation..Two.contact.closures.and.one.output.coil.are.placed.
on.network...They.are.assigned.addresses.I0.0,.I0.,.and.Q0.0..
Note.that.in.the.statement.list.a.new.logic.operation.always.
begins.with.a.load.instruction.(LD)..In.this.example.I0.0.(input.).
and.(A.in.the.statement.list).I0..(input.2).must.be.true.in.order.
for.output.Q0.0.(output.).to.be.true..This.same.logic.is.also.
shown.in.a.function.block.diagram..
The.following.truth.table.represents.the.state.of.the.output.for.
each.combination.of.input.states.
I0.0 I0.1 Q0.0
0 0 0
0 1 0
1 0 0
1 1 1
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