Controlling 24v AC Loads
Archiver
Posts: 46,084
Looking for the best way to control a 24v AC load (outdoor sprinkler
valve). Total current for the valve is about 200mA.
Is it easiest to drive a simple relay from the Stamp or is there a
better non-mechanical solution.
Appreciate any information or examples.
John
valve). Total current for the valve is about 200mA.
Is it easiest to drive a simple relay from the Stamp or is there a
better non-mechanical solution.
Appreciate any information or examples.
John
Comments
simplicity and reliablility goes. Although a solid state relay like a triac
or SCR might appear to be more reliable as it doesn't have any moving parts,
it may be susceptible to power glitches, spikes and such.
I'd use a driver of some sort between the stamp and the relay. Maybe a
simple 2n2222 transistor would be sufficient. If there is larger voltages,
you may want to use a opto-isolator chip like a PS2501 Quad IC pack, if your
planning on driving several or more relays.
Original Message
From: John D. Kerr [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=7YUR07lX3siLBpgkxRiHdcsxpWsvcDz_h0v5mKt9tXzdi6YoelNnyDYzRjdHIAcR2PEF7GBwtySM]jdkerr@p...[/url
Sent: Saturday, May 11, 2002 10:04 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Controlling 24v AC Loads
Looking for the best way to control a 24v AC load (outdoor sprinkler
valve). Total current for the valve is about 200mA.
Is it easiest to drive a simple relay from the Stamp or is there a
better non-mechanical solution.
Appreciate any information or examples.
John
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/
From what I have done in the past for multiple outputs
of the same variety (4 or greater), I tie the stamp
output pins to a darlington driver (like a ULN2003A).
The output of the darlington driver in question is
then connected to the output device, whether it is a
solid-state relay or a conventional relay. I do this
because it gives me the best flexibility for putting
together a project while keeping the overall output
current down (some of the solid state relays can take
up to 13 mA of current to operate so the power
requirements can add up quickly). I like what Earl
says about using a conventional technology versus
solid state relays; either one is acceptable and which
one you use is a matter of project parameters such as:
budget, heat dissipation, number of projected
operations in a day, voltage spikes/fluctuations on
the power system (which can be mitigated),
serviceability, and the list can go on.
If you need any further information, please let me
know.
Regards,
Gerry Shand
gshand@h...
Date: Sat, 11 May 2002 23:03:46 -0400
From: "John D. Kerr" <jdkerr@p...>
Looking for the best way to control a 24v AC load
(outdoor sprinkler
valve). Total current for the valve is about 200mA.
Is it easiest to drive a simple relay from the Stamp
or is there a
better non-mechanical solution.
Appreciate any information or examples.
John
__________________________________________________
Do You Yahoo!?
LAUNCH - Your Yahoo! Music Experience
http://launch.yahoo.com