siemens logo help

@Sidewinder? (or anyone else)

short version, have a logo with 2 inputs, 1 & 2 controlling output 1 (its a bit more complicated than that, but for the part im stuck with thats all i need)

what im trying to do: when input 1 is on i need output 1 on except if input 2 is on then input 1 must not be on (basically, input 2 is a stop signal). any hints?

So input 2 is a n/c contact.

NO but it can be inverted (both 'inputs' are the output of an AND & OR)

Is it something like this you're trying to do?

Edit

Ignore this , just seen new post

yep, that looks about it

So you need 

0 0 0

0 1 0

1 1 0

1 0 1

Andy,

Yes, I can help, I'm playing with Logo's at the moment too!

It should be straight forward, but, not after a gallon of lager, & 30+ minutes on the phone to GWR, don't ask.

Just so I am getting this you have:

IP1 (after processing a bit)  + Not IP2 (after a bit of processing) = OP1?

Or something else?

You might need to use flags or markers to get this to work so that you have an intermediate step.

Just remember though that a stop control must overrule everything else, and I hope its not safety related as the Logo isn't.

I am out first thing in the morning, for a few hours, and probably at home working on a 10 ip, 8 op Logo programme and an engine controller programme, so I'll have my Siemens PG out.

Steps has gone to the whole truth table version!

That's about as far as my knowledge stretches to,

I was just thinking it may help someone else understand what Andy wants to achieve.

it should be straight forward but i cant figure it out. its nothing safety related (most dangerous thing it does is turn on a 12-230 inverter in my van)

so far i have an AND & OR gate. output from AND is input 1, output from OR is input 2. input 2 is the stop, input 1 needs to get to the output unless input 2 is on

steptoe said:

So you need 

0 0 0

0 1 0

1 1 0

1 0 1

Click to expand...

yep, thats it. just cant figure out how to achieve it

Just connect input 1 to output 1 via a relay that is controlled by input 2.

no suitable relays on there that i can see?

On/off delay with timer set to zero.

Input 1 to relay trigger, input 2 to reset. Output to output 1.

so simple...

That reminds me, I'm supposed to be doing a job with a Logo this week, need to find out what it was!`

even simpler...use an AND gate with an inverted input... why has it taken me 2 hours to figure that out...

Andy™ said:

even simpler...use an AND gate with an inverted input... why has it taken me 2 hours to figure that out...

Click to expand...

Not sure that will work. What happens when the stop button is active and the input is off? Probably makes more sense with all your extra logic though.

Andy™ said:

even simpler...use an AND gate with an inverted input... why has it taken me 2 hours to figure that out...

Click to expand...

Sometimes you just can't see the wood for the trees,

That's why a different set of eyes is such a good help at times like this.

You think so hard about stuff you overcomplicate what can be something simple.

A nudge in the right direction and you realise its actually somuch easier than you were making it.

I'll not even mention it was down to my logic table, 

:innocent

:coat

:slap

Lurch said:

Not sure that will work. What happens when the stop button is active and the input is off? Probably makes more sense with all your extra logic though.

Click to expand...

It only works when 

1 is 1

And

2 is 0

Lurch said:

Not sure that will work. What happens when the stop button is active and the input is off? Probably makes more sense with all your extra logic though.

Click to expand...

but it did work... i tried it before i posted

Andy™ said:

but it did work... i tried it before i posted

Click to expand...

Ah yeah, I read that as inverted output. My bad. You've made me fire up the software now, I was supposed to be getting up and leaving the computer for tonight then.

steptoe said:

Sometimes you just can't see the wood for the trees,

That's why a different set of eyes is such a good help at times like this.

You think so hard about stuff you overcomplicate what can be something simple.

A nudge in the right direction and you realise its actually somuch easier than you were making it.

I'll not even mention it was down to my logic table, 

:innocent

:coat

Click to expand...

usually the way things go, missed the obvious looking for something else