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Can not completely turn off LEDs on 1031 LED 64 output card

Posted: Fri Jun 15, 2012 10:29 am
by electro

I have used several Phidgets cards with great success but now I'm having a problem with my brand new 1031 LED64 output card.
It works very well in all ways except that I can't seem to turn the LEDs off completely.

A simple test case is to connect a single LED to an output port and use the Phidget Control Panel to set the voltage and current limit to match the LED's specification. The LED lights up all and well and with the LED brightness slider I can indeed control the brightness. However, setting it to the far left (i.e. 0), will not completely turn off the LED.

Using a small test program to call CPhidgetLED_setDiscreteLED(handle, index, 0) yields the same results (100 = full brigtness, 0 = not bright but not completely turned off). If I understand the documentation correctly, setting the current limit to 0 should effectively block all current to the output port but this does not seem to be the case.

It's the same result with all the different output ports and I've tried several different LEDs with different specifications from different manufacturers, and all possible combinations of voltage and current limit settings. The result is always the same - when setting a working voltage and current limit, the LED can never be turned off

Any help with this issue would be much appreciated.

Re: Can not completely turn off LEDs on 1031 LED 64 output c

Posted: Sat Jun 23, 2012 3:55 am
by electro
No ideas?
It seems like I won't be able to use this card then :(

Re: Can not completely turn off LEDs on 1031 LED 64 output c

Posted: Mon Jun 25, 2012 8:48 am
by Patrick
This behaviour is not expected - setting the brightness to 0 should completely turn off the LED. We have tried with several of our LEDs. Are you seeing this behaviour with any of the LEDs we sell?

What are you using as a power supply? I used a 12V 2A.

I think you may have a damaged board, in which case you should contact the seller for a warranty replacement.