Proximity Switches
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Posts: 46,084
Hi Loren,
Go to Parallax web site:
http://www.parallaxinc.com/html_files/products/BS_Board
s/bsio.asp
and download the documents dealing with these
Industrial controls.
Inside you will find information on how to use/wire up
the two types of
Proximity switches out there.
One problem is that most proximity switches require at
least 12 volts and
many may prefer 24 volts to run. NPN vs. PNP types are
wired differently.
Due to the higher voltage requirement NPN may be used
to pull down a
resistor tied to +5 buss, however a PNP is best used
with an opto isolator,
though one could use other circuitry. Optos simplify
and isolate the logic 5
volts from all sorts of issues that may bite.
Sincerely,
Ron
>
> Message: 1
> Date: Fri, 08 Mar 2002 12:49:39 -0000
> From: "lrysavy" <lerysavy@h...>
> Subject: Proximity Switch and count Function
>
> I am trying to build a wind speed indicator and
decided to use a
> proximity switch and a Basic Stamp 2 to count the
switch closures and
> then calibrate the wind speed from the total count.
The problem I am
> having is I can not get a consistent reading from the
proximity
> switch. The readings are all over the map (From 0
sometimes up to 150)
> as I try and trigger the prox. The code I am using is
as follows:
>
> '($StampBS2)
> Speed Var Word
> Again:
> Count 1, 500, Speed
> Debug CLS, Dec ?, Speed
> Low 1
> Goto Again
>
> Note I had to add the Low 1 command to get any type
of reading. Any
> help would be appreaciated.
> Thanks Loren
Go to Parallax web site:
http://www.parallaxinc.com/html_files/products/BS_Board
s/bsio.asp
and download the documents dealing with these
Industrial controls.
Inside you will find information on how to use/wire up
the two types of
Proximity switches out there.
One problem is that most proximity switches require at
least 12 volts and
many may prefer 24 volts to run. NPN vs. PNP types are
wired differently.
Due to the higher voltage requirement NPN may be used
to pull down a
resistor tied to +5 buss, however a PNP is best used
with an opto isolator,
though one could use other circuitry. Optos simplify
and isolate the logic 5
volts from all sorts of issues that may bite.
Sincerely,
Ron
>
> Message: 1
> Date: Fri, 08 Mar 2002 12:49:39 -0000
> From: "lrysavy" <lerysavy@h...>
> Subject: Proximity Switch and count Function
>
> I am trying to build a wind speed indicator and
decided to use a
> proximity switch and a Basic Stamp 2 to count the
switch closures and
> then calibrate the wind speed from the total count.
The problem I am
> having is I can not get a consistent reading from the
proximity
> switch. The readings are all over the map (From 0
sometimes up to 150)
> as I try and trigger the prox. The code I am using is
as follows:
>
> '($StampBS2)
> Speed Var Word
> Again:
> Count 1, 500, Speed
> Debug CLS, Dec ?, Speed
> Low 1
> Goto Again
>
> Note I had to add the Low 1 command to get any type
of reading. Any
> help would be appreaciated.
> Thanks Loren