Help building a test box

[Doug22]

Need help in assembling a test box using off the shelf parts if possible. Simplicity in training someone to use would be a big plus. What the box needs to do is cut AC power (110vac) to a unit under test 10 milliseconds after a trigger (source is 12-24vdc) is applied. AC power would then be reapplied so a tester could document what happened on power up. The test would be repeated increasing time after trigger in increments of 10 milliseconds until a total of about 4 seconds is achieved. Any help or suggestions would be greatly appreciated.

 

[nbucska]

Do you need one or more ? The description is not too clear,
could you clarify it?

The problem itself seems to be simple .


<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[OperaHouse]

I just saw one of these on eBay a week ago for $75 when I was searching "ac power" for a variable frequency power supply. I thought to myself, who would want one of these. Now I know. You could look under completed auctions. Likely it didn't sell and you could contact them to relist it.

 

[Doug22]

Nbucska…..I’ll try and clarify.
I need one test box that could trigger from various transaction systems used in a kiosk. The embedded systems operate from 12 to 24 volts DC supplied from the kiosk. What I need to do is kill power to the kiosk at various time intervals after a transaction is started and document results when power is reapplied.

The test would be as follows:
? Triggering from transaction system number one, kill power to the kiosk 10 milliseconds into a transaction then reapply power and have results documented.
? Triggering from same device, kill power 20 milliseconds into transaction, reapply power and document results.

Each test would add additional 10 milliseconds before killing power.

I would assume a digital timer capable of triggering from a 12 to 24 volt DC signal is needed. A solid state relay could then be activated to kill the AC power. I have searched some catalogs but seem to be having problems putting this together. Again any help is appreciated as I come more from a mechanical background.

 

[Skogsgurra]

Sounds like a micro and an SSR. Ask an engineering school near you to make one as a project for a beginner's class in electronics. But do not expect that they know about NEC...

 

[nbucska]

"Document result" may be recording one single digit (e.g.
0 = lamp is off, = on etc.) or record a phonebook of 2000
pages...

In any case the simplest seems to be using a PC with a SSR.


<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[Mike2468]

Using a timing circuit and a SSR is easy. You could build the circuit or just use a tiny PLC such as:

http://web1.automationdirect.com/adc/Shopping/Catalog/PLC_Hardware

if you want flexibility in the timing patterns and repetition.

Then take the dc logic output to an ac switching SSR such as:

http://www.power-io.com/products/dda2540.htm

A zero crossing SSR turns on and off at the sinewave's zero mark that occurs every 8.3 milliseconds. Therefore, if you tell it to turn on, it will wait till the next zero mark. There are "random firing" SSRs, but then there are additional electronic noise issues to be addressed.

Off the shelf hardware, meets electrical codes when properly installed, easy to program, using a local engineering school for assistance is a great idea.