12 Volt when active, grounded when not

Hello All, Please excuse my lack of jargon. If i knew what the circuit was called i could have googled it and not have had to ask here but i’m at a loss. I have a sensor and one of the wires needs to be grounded except when you want it to perform its task, then it needs 12 volts. How do I accomplish this? Using diodes?

(Excuse my ignorance, I may be an engineer but i like the things that move not the way to power them :smiley: )

I included the diagram that have for the input circuit. This may give me what i want but i do not understand it. And with the sensor being several thousand dollar, i want to understand it.

I don't see a diagram. Sounds like all you may need is a pullup resistor to 12V, and then a simple transistor to buffer an Arduino output to pull it low when the Arduino output goes high.

It was blocking me from adding it for too frequent posting. Should be there now.

Could you point me to a diagram that would depict this? I really only understand this stuff if i can visualize it.

I have a sensor

Which I am keeping a big secret. I am not telling you if it is an analogue sensor or a digital one. I am not telling you how often I want to read it, or what voltage it outputs.

I really only understand this stuff if i can visualize it.

But you expect us to read your mind, sorry crystal ball is on the blink.

Please read this:-
How to use this forum

And make the most of your posts during the time limited portion of your membership here.

Lol Grumpy_Mike has a fitting name.... People make mistakes.

The sensor is a baumer laser distance sensor OADM 21l6581/S14F, analog output. It has a teach in button that allows the user to set min and max distances. When the teach in button is not being used, it should be grounded. When it is required, it takes 12 volts. I am needing a circuit to do this. My basic way of doing it would be to wire it to a relay and the relay to 12 volt, but since it needs to be grounded when not is use, i was confused.

http://www.baumer.com/us-en/products/productfinder/?tx_baumerproductfinder_pf=http%3A%2F%2Fpfinder.baumer.com%2F%2Fpfinder_sensor%2Fscripts%2Fsearchresult.php%3Ftype%3Dproduct%26cat%3DCONFMyAppli%26pid%3DOADM_21I6581_S14F%26language%3Den

Being a computer warrior doesn't help. I realize now that that information was needed and I should have included it in the first post. I enjoy trying to figure this stuff out but when people respond when such aggressiveness, it just makes me feel even worse about not knowing it. I'll try harder next time....

I was thinking something like this.
The “1K” in the note is actually the 220 from the Arduino 5V pin, got a little out of sync with myself.Sensor 12V drive.jpg

but when people respond when such aggressiveness,

No aggressiveness, just sarcasm.

bmlaumer: Hello All, Please excuse my lack of jargon. If i knew what the circuit was called i could have googled it and not have had to ask here but i'm at a loss. I have a sensor and one of the wires needs to be grounded except when you want it to perform its task, then it needs 12 volts. How do I accomplish this? Using diodes?

(Excuse my ignorance, I may be an engineer but i like the things that move not the way to power them :D )

I included the diagram that have for the input circuit. This may give me what i want but i do not understand it. And with the sensor being several thousand dollar, i want to understand it.

The line at the bottom of things that is just a horizontal line is what is called "ground" or common. It or they must be connected back to the box supplying the circuit 12 volts so the electrons can complete their "circuit". Also the output going out the right side needs the common or "ground" continuing out the right side, also, and connected to the "ground" of whatever is over there. So both sides need their complete, individual, circuit.

The common or grounds of all parts need to be connected together.

Paul

Could try this one too ... as somebody mentioned already, maybe a pull-down resistor will do the job, to give the sensor a 0V input when the sensor is unpowered.

bmlaumer:
I included the diagram that have for the input circuit. This may give me what i want but i do not understand it. And with the sensor being several thousand dollar, i want to understand it.

567529f0ff1c529ed02ca3668900ea7690d775a5.png

If a DC voltage is applied across the two outer-most terminals on the left-hand-side (across the 27k and 10k resistor combination), and if the applied voltage is initially zero Volt, and we gradually increase the voltage, then the middle node will eventually reach 3.3 Volt. But, from there onward, any further increase in the supply voltage will not change the node voltage of 3.3 Volt (under normal operating conditions). This is because the diode connected there is a zener diode. And this particular zener diode has a zener voltage of 3.3 Volt. This circuit doesn’t appear to suitable for what you want to do.

Southpark: This circuit doesn't appear to (be) suitable for what you want to do.

The circuit shown, was actually the input circuitry of the sensor in question! See page 48 of the user manual.

JohnLincoln: The circuit shown, was actually the input circuitry of the sensor in question! See page 48 of the user manual.

I see. Thanks. Yeah...... not sure what this input circuitry is supposed to do for the sensor. All I can see right now with that circuit is that the zener is going to limit the middle node voltage to maximum of 3.3 V. When the input voltage applied to the left-hand-side is approx 12 V, then the middle node voltage reaches roughly around 3.3 V.

All that circuit does is : when input is between 0 and 2 volts output is considered Low (for 2 V input output will be around 0.5 volts or so) When input is between 12 and 28 volts, output is considered High ( actually clamped by the zener at 3.3 volts)

Between 2 volts and 11 volts output could be roughly between 0.5 and 3volts and may be considered “unknown” logic state. Or putting it another way a pretty poor state of affairs.

All that circuit is, is to supply a 0 or 3V3 logic level signal to the "teach input" of the sensor, it is nothing to do with the analogue output of the sensor. You could replace that circuit with a push button between a 3V3 source and a pull down resistor. If you don't want to use the "teach input" then just wire the input to ground or 3V3. There is a 3V3 regulator on most Arduinos that can supply this voltage.

Grumpy_Mike: All that circuit is, is to supply a 0 or 3V3 logic level signal to the "teach input" of the sensor, it is nothing to do with the analogue output of the sensor.

Thanks GM! I didn't know what a teach input was a moment ago, until you mentioned it. So I looked up a definition from one site here:

http://www.sensor.si/data/pdf/2_slovar.pdf

....which says "A function by means of which the sensor is caused to automatically calculate and save future settings based upon momentarily acquired values by pressing a button or applying a control signal"

  • which is kind of confusing, since it's saying 'save future settings'. I was gathering it should really say 'save settings at the time of the application of the trigger/teach signal/command'. Or they could be meaning something like - we apply a teach-in command signal in the 'future' in order to save settings in the future (at whatever time we call up that command).

I need to do more definitions checking.

The function of the teach input is in the manual of the sensor that was posted.

Somebody on this thread posted a manual. Unfort I don't know how to read german writing.... which I had flicked through yesterday. And won't be looking for an english version. However I will keep searching for a clear definition of 'teach input'.

Unfort I don't know how to read german writing

But from page 32 it is in English.

Thanks for the heads up GM. I'll take a look at the manual again.