Arduino Forum

Using Arduino => Motors, Mechanics, and Power => Topic started by: enen92 on Jul 04, 2013, 12:44 am

Title: Yet another SSR topic
Post by: enen92 on Jul 04, 2013, 12:44 am
Hi all,

First of all my apologies to bring again another topic about solid state relays. I've bought the starter kit and completed all the beginners projects included in the kit, so I think I have now what is required to start moving forward to something more close to a proper use of Arduino.

I'm thinking about buying some SSR to control some 230VAC devices (lamps mainly). I know how to choose them according to the main line voltage/amperage and also to the arduino's side "limitations". My question is about a way to find if the main circuit is connected from the arduino side. For example, if I decide to connect a SSR to a lamp and to the arduino how can I know if the lamp is turned on from the arduino if I switch the lamp on through a switch connected in paralel with the relay?

An SSR is a "special kind" of octocoupler, so it has a LED. Does this mean that if the main circuit is on (switched from the arduino or from the mechanical switch) the SSR led will always be on and that the value I get from the arduino digital pin is always HIGH? Or on the other I can only turn the SSR led on from the low DC power side?

Regards and thanks in advance for all the help you may provide

Title: Re: Yet another SSR topic
Post by: Grumpy_Mike on Jul 04, 2013, 05:29 am
Quote
how can I know if the lamp is turned on from the arduino if I switch the lamp on through a switch connected in paralel with the relay?

Basically you can't without providing an opto coupler in the reverse direction.

Quote
An SSR is a "special kind" of octocoupler,

No it is not.

Quote
Does this mean that if the main circuit is on (switched from the arduino or from the mechanical switch) the SSR led will always be on

No
Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 01:20 pm

...
An SSR is a "special kind" of octocoupler, so it has a LED. Does this mean that if the main circuit is on (switched from the arduino or from the mechanical switch) the SSR led will always be on and that the value I get from the arduino digital pin is always HIGH? Or on the other I can only turn the SSR led on from the low DC power side?
...


I think I got what you concerned. It is perfect point.

(http://s8.postimg.org/hjgvhw7vp/led_life_span.jpg)

The led of SSR has life span. if SSR is on most of time, your idea will help a lot for extend led life span. and implementation is easy and just inverter opto-isolator. However at practical is no go,  the deal stopper is low DC power side power failure will cause high AC side is on. It is not acceptable.
Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 01:39 pm

...
I'm thinking about buying some SSR to control some 230VAC devices (lamps mainly). I know how to choose them according to the main line voltage/amperage and also to the arduino's side "limitations". My question is about a way to find if the main circuit is connected from the arduino side. For example, if I decide to connect a SSR to a lamp and to the arduino how can I know if the lamp is turned on from the arduino if I switch the lamp on through a switch connected in paralel with the relay?
...


What you ask is AC voltage/current sensor or monitor. We have some thread about it, see if it is helpful, otherwise post back here we will sharp the pencil.

http://forum.arduino.cc/index.php?topic=162326.msg1277450#msg1277450 (http://forum.arduino.cc/index.php?topic=162326.msg1277450#msg1277450)
Title: Re: Yet another SSR topic
Post by: Grumpy_Mike on Jul 04, 2013, 03:37 pm
Quote
if SSR is on most of time, your idea will help a lot for extend led life span. and implementation is easy and just inverter opto-isolator. However at practical is no go,  the deal stopper is low DC power side power failure will cause high AC side is on. It is not acceptable.

WTF is that supposed to mean? It is gobbledegook at best totally wrong at worst.

Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 04:19 pm

...
WTF is that supposed to mean? ...
...


Is that your standard way to speak at public forum?
Title: Re: Yet another SSR topic
Post by: retrolefty on Jul 04, 2013, 05:03 pm


...
WTF is that supposed to mean? ...
...


Is that your standard way to speak at public forum?


Well his name does start with Grumpy  ;)

How about you just restate whatever you were trying to say as it wasn't at all clear to me also. Or not if you so wish.

Lefty
Title: Re: Yet another SSR topic
Post by: Grumpy_Mike on Jul 04, 2013, 06:22 pm

Is that your standard way to speak at public forum?

No it is a special term I reserve for members who give irrelevant and wrong advice persistently despite several previous warnings.

Let's try and pick the bones out of your comments. I will assume that you are not a native English speaker so lets not dwell on things like sentence construction although it does make things hard to read.

Quote
However at practical is no go,  the deal stopper is low DC power side power failure will cause high AC side is on.

A power failure on the DC side, I assume that is the LED side would not result in the AC side being on, it would result in the triac not being triggered and so no conduction would take place, the same situation as when it were off. So your comment here is just plain wrong.

Quote
if SSR is on most of time, your idea will help a lot for extend led life span.

The LED in an SSR is the most reliable component in the circuit and so the least likely to fail so extending the life span on it is not going to affect the overall performance of the component.

PLAN F
Only post when you know what you are talking about. If you are not sure on a topic and still feel you would like to contribute then acknowledge the fact in a preamble, like I am no expert but ... or I think you might ....

Remember, I have told you before, this is a beginners forum and it is incumbent upon you to give clear, accurate, relevant advice, not flights of fancy.

From the OP
Quote
Or on the other I can only turn the SSR led on from the low DC power side?

Yes that is correct.
Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 07:07 pm

...
How about you just restate whatever you were trying to say as it wasn't at all clear to me also. Or not if you so wish.

Lefty


Sure;

(http://s21.postimg.org/618efk6uf/ssr_schematic.jpg)

DC turn on; AC turn on.
DC turn off; no current through LED, AC turn off.
But led life span if on time is long.

By Inverter opto-isolator;-

DC turn on; AC turn off.
DC turn off; no current through LED, AC turn on.
The led life span is good now, but in case DC side power failure then AC keep turn on. It is the deal stopper.
Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 07:13 pm

...
Let's try and pick the bones out of your comments. I will assume that you are not a native English speaker so lets not dwell on things like sentence construction although it does make things hard to read.



You get that right;-
English is my third one, among Chinese, Japanese.
My next one and I wish not last one is;-


?   d7 93        HEBREW LETTER DALET
?   d7 a0        HEBREW LETTER NUN
?   d7 99     HEBREW LETTER YOD

in my life, this is first time typing copy and paste Hebrew and hope I get it right. if I get it right I will learn HEBREW after retire.

I think billroy is correct it is UTF-8 encode, all I do is see translation table now.

Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 07:58 pm
Quote
Remember, I have told you before, this is a beginners forum and it is incumbent upon you to give clear, accurate, relevant advice, not flights of fancy.


Totally disagree, Electronics is very board science, so many vertical field. I found a lot of OP has so deeply knowledge need me multiple lifetimes (I overestimate my skill, at most case I never) to catch. Might be that is your problem treat every one beside yourself as beginner.
Title: Re: Yet another SSR topic
Post by: AWOL on Jul 04, 2013, 10:52 pm
Quote
Totally disagree

You're allowed to disagree (but I'll reserve the right to disagree with you because it is a forum largely for beginners), but if you carry on posting content-deficient bollocks, and you'll find yourself on the wrong end of a ban.
Title: Re: Yet another SSR topic
Post by: sonnyyu on Jul 04, 2013, 11:32 pm

Quote
Totally disagree

You're allowed to disagree (but I'll reserve the right to disagree with you because it is a forum largely for beginners), but if you carry on posting content-deficient bollocks, and you'll find yourself on the wrong end of a ban.

"content-deficient bollocks" ?  I am more than happy to find out where?


Title: Re: Yet another SSR topic
Post by: retrolefty on Jul 05, 2013, 12:00 am
Well I'm of the opinion that LED life is not an issue to be concerned with in a component like an SSR. I suspect the triac would have a worst MTBF rate then a low current LED.

Lefty