Baffled by Honeywell proximity sensor

Guest
I've been given a sample Honeywell capacitative proximity sensor by a
client. He wants me to build a small micro-based project to interface
with it. The sensor is shipped in a bag labeled "992AA12AN-A2", and the
documentation for "992 series" sensors consists of four letter-sized
sides, most of which are multilingual translations of warnings and
mechanical specs. The electrical documentation supplied with this
sensor is a quarter-page and not very meaningful to me. I've
photographed it at http://www.larwe.com/honey.jpg - sorry for the nasty
photo, my scanner is being recalcitrant.

The device has a blue wire, a brown wire and a black wire. Looking at
those diagrams - I presume they relate to different versions of the
sensor - I assume that the blue wire is supposed to be +ve, the brown
is -ve, and the black is output. But when I connect a 10VDC supply and
a scope, all I see on the output is 60Hz hum. I added a 500 ohm
resistor between the "output" line and ground, and still all I get is
hum. The device also doesn't seem to be drawing any appreciable
current.

The only info I can find on the web is a bunch of people offering to
sell me the datasheet, and one company saying that they have stopped
selling it and now sell someone else's sensor.
Does anyone know how these devices are supposed to work?
 
larwe@larwe.com wrote:
I've been given a sample Honeywell capacitative proximity sensor by a
client. He wants me to build a small micro-based project to interface
with it. The sensor is shipped in a bag labeled "992AA12AN-A2", and the
documentation for "992 series" sensors consists of four letter-sized
sides, most of which are multilingual translations of warnings and
mechanical specs. The electrical documentation supplied with this
sensor is a quarter-page and not very meaningful to me. I've
photographed it at http://www.larwe.com/honey.jpg - sorry for the nasty
photo, my scanner is being recalcitrant.

The device has a blue wire, a brown wire and a black wire. Looking at
those diagrams - I presume they relate to different versions of the
sensor - I assume that the blue wire is supposed to be +ve, the brown
is -ve, and the black is output. But when I connect a 10VDC supply and
a scope, all I see on the output is 60Hz hum. I added a 500 ohm
resistor between the "output" line and ground, and still all I get is
hum. The device also doesn't seem to be drawing any appreciable
current.

The only info I can find on the web is a bunch of people offering to
sell me the datasheet, and one company saying that they have stopped
selling it and now sell someone else's sensor.
Does anyone know how these devices are supposed to work?

From what I can tell, you have a NPN Capacitive Prox switch that roughly
Click to expand...
works like this.

Brown - Connect to DC positive 9 - 30 Volts
Blue - Connect to DC Common, in most cases this should be machine ground
Black - When not triggered, will have the same potential as Brown
- When triggered, will have the same potential as Blue

The switch can handle upto 200 milliamps if it's the 12mm version
through the black wire. It will incur a voltage drop of 1.75 volts
if you pull the maximum load across the black wire. The switch consumes
15 milliamps by itself at most in addition to your load. Your load must
be greater than 50 microamps to guarantee the switch will turn off the
output.

There is also a line concearning the maximum switching frequency that
you did not show. Usually for DC it's a few hundred hertz for this
type. I have seen as high as 50 kilohertz in some special inductive
units.
 
Hi,

Thanks for the reply.. the switch frequency is not shown in that
datasheet. And I'm just about to run out the door, but I quickly tried
the wiring configuration you suggested and I still get exactly the same
results. I'd say the sensor must be bad, but I cut open the factory
packaging myself so it seems _fairly_ unlikely. Very bizarre.

Also, how did you decide that it was NPN? The "wiring diagram" has me
puzzled. I can't work out if it is showing the pinouts for four
different variants of the sensor, or if the left side is supposed to
show what you're connecting it to in whatever the intended application
might be.
 
larwe...
I've been given a sample Honeywell capacitative proximity sensor by a
client. He wants me to build a small micro-based project to interface
with it. The sensor is shipped in a bag labeled "992AA12AN-A2", and the
documentation for "992 series" sensors consists of four letter-sized
sides, most of which are multilingual translations of warnings and
mechanical specs. The electrical documentation supplied with this
sensor is a quarter-page and not very meaningful to me. I've
photographed it at http://www.larwe.com/honey.jpg - sorry for the nasty
photo, my scanner is being recalcitrant.

The device has a blue wire, a brown wire and a black wire. Looking at
those diagrams - I presume they relate to different versions of the
sensor - I assume that the blue wire is supposed to be +ve, the brown
is -ve, and the black is output. But when I connect a 10VDC supply and
a scope, all I see on the output is 60Hz hum. I added a 500 ohm
resistor between the "output" line and ground, and still all I get is
hum. The device also doesn't seem to be drawing any appreciable
current.
Click to expand...
Supply connection looks OK. Low power (milliamp or so) is normal.

The output is open collector, either NPN (with emitter at -Ve) or PNP (with
emitter at +Ve).
You need to connect a 1 kOhm load resistor or the inactive output will be
floating, hence the 60 Hz hum (50 Hz in Europe...). With the load resistor
connected to a supply rail, activate the sensor (hold your hand or a piece
of metal on the face of it) and check if the output switches. If not,
connnect resistor to other supply rail and try again.


Regards,
Arie de Muynck
 
larwe@larwe.com wrote:

Hi,

Thanks for the reply.. the switch frequency is not shown in that
datasheet. And I'm just about to run out the door, but I quickly tried
the wiring configuration you suggested and I still get exactly the same
results. I'd say the sensor must be bad, but I cut open the factory
packaging myself so it seems _fairly_ unlikely. Very bizarre.

Also, how did you decide that it was NPN? The "wiring diagram" has me
puzzled. I can't work out if it is showing the pinouts for four
different variants of the sensor, or if the left side is supposed to
show what you're connecting it to in whatever the intended application
might be.

look at the part number.
Click to expand...
normally the last Digit or charactor.
let N or P
 
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