"shorted triac" sensor

Hi Everybody!

[color=#202124]I need to detect if an Arduino-controlled triac is ok or shorted. there is a moc in between arduino and the triac. I wonder  I need another moc to send the triac status to some input pin but make no idea how. Thanks![/color]

Look at this link, it will tell show you how to test the triac , as far as the moc , don't know what that is.

In addition to the question of you term MOC, can you tell us the conditions you are working under? For instance are you trying to determine if the triac is shorted when it is normally ON or only when it is off?
What voltages is the triac switching?

Larryfos:
Look at this link, it will tell show you how to test the triac , as far as the moc , don't know what that is.
How to Test TRIAC with Multimeter - Inst Tools

Hi! Thank you! "moc" is an optocoupler that drives de triac

JohnRob:
In addition to the question of you term MOC, can you tell us the conditions you are working under? For instance are you trying to determine if the triac is shorted when it is normally ON or only when it is off?
What voltages is the triac switching?

Thanks JohnRob! Imagine that I am controlling a traffic lights... I send 5V from arduino pinout (green light) to the MOC and then turn the (green) triac ON. OK, I need to know (arduino) when this triac is shorted and then put the system in intermitent yellow to prevent acidents. When this (shorcut) occurs the green light "ON" all the time can cause a dangerous conflit. With this sensor I can turn off a ralay that deactivate all the greens in the crossroad.

There are a few ways of determining if the power is on. Of course, the AC power has to remain isolated from the low voltage...

A relay with a 120V (or 240V) coil will work. Some people use a 5V wall-wart power supply. You can also use an opto-isolator. (And opto-isolator needs a power resistor rated for about 2W). Then of course, your software has to compare the on-off state to whatever is expected.

Or, a photo-transistor or LDR could be used to detect the actual light and then you'd know if the light was stuck-on, or burned-out or stuck-off.

FYI, 'SHORTED' is the term used by engineers to describe a DAMAGED triac. The term your topic title should use is 'ON' , denoting an UNDAMAGED triac that is turned ON. There are many ways to do this not the least of which is an optocoupler with a series diode and resistor in parallel with the load which will turn on during the positive phase of the AC. Using the period of the ac frequency you can count the pulses and detect 'triac on'. The output is pulled up with a resistor and is low when on.

raschemmel:
FYI, 'SHORTED' is the term used by engineers to describe a DAMAGED triac. The term your topic title should use is 'ON' , denoting an UNDAMAGED triac that is turned ON. There are many ways to do this not the least of which is an optocoupler with a series diode and resistor in parallel with the load which will turn on during the positive phase of the AC. Using the period of the ac frequency you can count the pulses and detect 'triac on'. The output is pulled up with a resistor and is low when on.

I mean DAMAGED. the quest is to detect a damaged triac! thank you!

Looks like the way is using an opto, I have seem some boards without them so I thougt to find other way. Thank so much everone!

I mean DAMAGED. the quest is to detect a damaged triac! thank you!

Same method only look for the low when the code says it should be high. If the opto output is low when the code
says the triac should be off (which means the output should be HIGH) , then the triac is DAMAGED.

Also, FYI, I don't know how you entered the text on your original post but don't do that.
It's very inconvenient when trying to read it. Just type in or paste in your text.

You can use a h11aa1 with a suitable resistor across the load. With this setup you can only sense the triac condition when it is/should be Off.

Else you could use a small current transformer to measure the triac current, again when it should be off.

I used a toroid CT to sense computer monitor AC
current when it goes to sleep to energize a relay which disconnected the internet cable so it was impossible for anyone to hack into the computer
when unattended. (it wasn't my idea. I was hired
by a client to design and build a prototype which
worked so well he ordered at least one more.
(1998)

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