Control of 120VAC with stamp2sx
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Posts: 46,084
I am controlling a 120VAC (household 110 AC) using a stamp...I have
had two successful methods so far and would like some opinions on
the best way to achieve this as I keep getting conflicting advice.
The two methods are 1. use of a triac and 2. use of a 5V coil
relay with 120VAC 5A rating on the ports.
What are the advantages and disadvantages of each method? What do
you folks think about the best way to do this...I am only pusing 65
watts on the AC appliances that are being controlled.
Thanks for the advice - any schematics that you would all like to
send would be great too....
Thanks a bunch....
Bill
had two successful methods so far and would like some opinions on
the best way to achieve this as I keep getting conflicting advice.
The two methods are 1. use of a triac and 2. use of a 5V coil
relay with 120VAC 5A rating on the ports.
What are the advantages and disadvantages of each method? What do
you folks think about the best way to do this...I am only pusing 65
watts on the AC appliances that are being controlled.
Thanks for the advice - any schematics that you would all like to
send would be great too....
Thanks a bunch....
Bill
Comments
I wouldn't connect a triac directly to any device (stamp or
otherwise) that I had paid that much for! Go to RadioShack and get a solid
state relay rated for what you are using. I think they sell a Toshiba or
Sharp (I think the model number is a S202S02, but I don't remember the RS
number). Easy to use and optically isolated! Safe for your stamp.
Good Luck,
Mike
At 04:50 PM 3/18/2002 +0000, you wrote:
>I am controlling a 120VAC (household 110 AC) using a stamp...I have
>had two successful methods so far and would like some opinions on
>the best way to achieve this as I keep getting conflicting advice.
>
>The two methods are 1. use of a triac and 2. use of a 5V coil
>relay with 120VAC 5A rating on the ports.
>
>What are the advantages and disadvantages of each method? What do
>you folks think about the best way to do this...I am only pusing 65
>watts on the AC appliances that are being controlled.
>
>Thanks for the advice - any schematics that you would all like to
>send would be great too....
>
>Thanks a bunch....
>
>Bill
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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>Body of the message will be ignored.
>
>
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_________________________________
Mike Walsh
walsh@i...
[noparse][[/noparse]Non-text portions of this message have been removed]
>I am controlling a 120VAC (household 110 AC) using a stamp...I have
>had two successful methods so far and would like some opinions on
>the best way to achieve this as I keep getting conflicting advice.
>
>The two methods are 1. use of a triac and 2. use of a 5V coil
>relay with 120VAC 5A rating on the ports.
>
>What are the advantages and disadvantages of each method? What do
>you folks think about the best way to do this...I am only pusing 65
>watts on the AC appliances that are being controlled.
Depends upon the load and how often you want to turn the load on and off.
1) Triac / opto combination: can choose between zero-crossing and random
triggering (depending which opto you use).
1a) Zero cross switching increases light bulb life significantly and
generates less RF noise than either a relay or triac with a non-zero-cross
opto. Does not drive inductive load well. Cannot be used for dimming
light bulbs. Use a MOC3031 opto with your triac.
1b) Random trigger opto with triac is what you would use if driving an
inductive load or if you wanted to dim light bulbs. MOC3011 opto.
2) Relay - best general purpose output available. Does not care if the
load is resistive or inductive so long as you include an appropriate
snubber or transient voltage suppressor (MOV). Great for controlling
relays, motors, lights, etc. Is not a clean and quiet as (1a) above. Not
a good choice if the load has to be turned on and off millions of times - a
triac is better for that.
I tend to use relays for general purpose type loads (where I don't know
that the end user is going to connect to) and use triacs if I am driving
light bulbs.
A great little relay is the Omron JS1E series - they cost about a dollar in
large quantities and are very reliable. I also like the American Zetler
AZ-2150A (single NO (form A) contact rated at 30 Amps).
Triacs: I currently use BTA16-400 (16A 400V) and BTA41-400 (40A 400V).
Optos: MOC3011 (non-zero-cross) and MOC3031 (zero-cross).
Blatant plug follows: we make real nice little triac cards for 4 and 8
channel applications. Although intended primarily for night club lighting,
they are great for most hobbyist 120V interfacing. Each channel is
individually fused; triacs and optos are socketed. I'll make them
available as a kit for those who want to take a look at them - write
PRIVATELY for details.
dwayne
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
Celebrating 18 years of Engineering Innovation (1984 - 2002)
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operates the contacts and the load you are controlling with the contact
closures.
In your application the stamp output pin would be connected to a relay coil
and it's associated coil return path back to the Stamp Grd. pin. This
provide full electrical isolation of the DC potential on the Stamp from the
AC voltage on the switching contacts on the relay that you are controlling
.
Any other device that has a common pin between the input and output signals
where the output signal is connected to the 110/220 volt power lines is a
safety hazard and does not comply with the National Electrical Code
isolation and leak current requirements. If you find it compelling to go
this way I suggest that you power the stamp power supply and the AC load you
are controlling only from an common outlet that is provided with a Ground
Fault Interrupter GFI receptacle.
Original Message
From: "williamfmccarthy" <tech@t...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, March 18, 2002 8:50 AM
Subject: [noparse][[/noparse]basicstamps] Control of 120VAC with stamp2sx
> I am controlling a 120VAC (household 110 AC) using a stamp...I have
> had two successful methods so far and would like some opinions on
> the best way to achieve this as I keep getting conflicting advice.
>
> The two methods are 1. use of a triac and 2. use of a 5V coil
> relay with 120VAC 5A rating on the ports.
>
> What are the advantages and disadvantages of each method? What do
> you folks think about the best way to do this...I am only pusing 65
> watts on the AC appliances that are being controlled.
>
> Thanks for the advice - any schematics that you would all like to
> send would be great too....
>
> Thanks a bunch....
>
> Bill
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Original Message
From: Chris Loiacono [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Hqkc8HeulWP76wXi6n70JlWWFeQWVCI95aUtHaQRINX5p7oGKhgfE6FxUQSouchJQqPt_Qf401LBjUR7Eg]chris@m...[/url
Sent: Tuesday, March 19, 2002 9:13 AM
To: 'basicstamps@yahoogroups.com'
Subject: RE: [noparse][[/noparse]basicstamps] Control of 120VAC with stamp2sx
There have been some good threads on this subject in the past. You may want
to search the Stamp archive for details.
I do a fair amount of work with Stamps and PICs controlling AC. The solid
state solution is almost always more reliable, as Dwayne says, especially
when the circuit will be cycled many times. Relays, Yeeeech! (sorry Dwayne)
For the tiny loads you are considering, Simple Triacs should do just fine.
The advice on snubbers and optical isolation is a must to follow, but the
end result will be super reliable @ 60W, while being compact and inexpensive
as well.
In a one-off pinch I have used the small TO-220 Triacs from RS for about
$1USD each and MOC3010's although I would never use 3010's for any line
voltage greater than 120V.
The RS Triac even has a simple circuit diagram on the back of the packaging
that actually works for this application.
The only shortcoming worth planning for that I have ever found with Triacs
is that when they fail, they tend to short, rather than burning open. They
are more heat sensitive than SCR's because both gates are connected to one
pin, but again, for 60W light bulbs, none of this should be a problem. If
you need a heat sink in this application, a tiny one will do.
If you wanted to reduce EM spikes, as you would have to do in Europe, there
are many zero-cross opto's designed to fire the gate only at the ZC. The
noise shouldn't be too bad at 120V with tungsten, so using random firing may
be OK for you unless....
If you intend to fire many Triacs on the same line, you should consider the
crosstalk that may occur. The spikes put ont the AC line at the gate firings
for one device may actually gate another. A fairly simple filter will solve
this, just be sure not to exaggerate the amount of capacitance on the gate
lines, likewise, try to keep the gate lead wires as short as possible.
If you are interested in this further, I will look up some good links to
post that will help with this.
Also, Have you seen the recent issues of N&V - there's a series of basics on
SCR's and Triacs that covers a wide range of applications and cures for
potential problems in the Jan thru March issues.
Chris
>
Original Message
> From: williamfmccarthy [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=LoQbIYRfUBXXIwzLcLcrqjljAw1Ar-vagEKLLGjNdZmmAZSMm_615GduFrfxkc9RiFv1Ls8DuK2ZTHyu1A]tech@t...[/url
> Sent: Monday, March 18, 2002 11:50 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Control of 120VAC with stamp2sx
>
>
> I am controlling a 120VAC (household 110 AC) using a stamp...I have
> had two successful methods so far and would like some opinions on
> the best way to achieve this as I keep getting conflicting advice.
>
> The two methods are 1. use of a triac and 2. use of a 5V coil
> relay with 120VAC 5A rating on the ports.
>
> What are the advantages and disadvantages of each method? What do
> you folks think about the best way to do this...I am only pusing 65
> watts on the AC appliances that are being controlled.
>
> Thanks for the advice - any schematics that you would all like to
> send would be great too....
>
> Thanks a bunch....
>
> Bill
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
That's why I recommend using an optically isolated solid state relay (4 pin
device). There is NO connection or current flow between the controlling and
controlled side. There is not contact arcing for your 65 watt load (if this
is a incandescent lamp, you will have as much as 20 times the instantaneous
current when you turn the lamp on due to the low resistance of the cold
filament) and if you use a zero crossing type you also have the advantage
of little RFI. Relays and contactors have their place but I don't see
switching a 65 watt load as that place.
Mike
At 11:23 PM 3/18/2002 -0800, you wrote:
>Any other device that has a common pin between the input and output signals
>where the output signal is connected to the 110/220 volt power lines is a
>safety hazard and does not comply with the National Electrical Code
>isolation and leak current requirements.
_________________________________
Mike Walsh
walsh@i...
[noparse][[/noparse]Non-text portions of this message have been removed]