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Prop-1 ULN loss question with solenoid operation

Started by gadget-evilusions, October 07, 2015, 07:40:06 PM

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gadget-evilusions

I have a 12vdc solenoid which lists it's draw at less than 100ma. Here is the item http://www.amazon.com/gp/product/B00V4PXQHE?psc=1&redirect=true&ref_=oh_aui_detailpage_o04_s00

After a few operations, I blew the ULN chip. I assumed this must have been due to voltage flyback from the solenoid's magnetic field dropping. I added a diode in an effort to send all that straight to ground. I had the stripe side of the diode on the OUT6 pin, and the non strip side to GND terminal.  The solenoid is connected to V+ and OUT6.

Even after adding the diode, a few operations cause the ULN to go bad again. Does anyone have any idea what could be causing this?
Brian
Evilusions LLC
www.evilusions.com for all your pneumatic components

JonnyMac

October 07, 2015, 09:12:48 PM #1 Last Edit: October 07, 2015, 09:17:11 PM by JonnyMac
When I saw that device I thought, "There's no way that runs at 60mA!" Then I clicked on the second product image and found Amazon has a typo in there product description. Look at the second image on the page -- it shows the current at 0.6A, that's 600mA and way above the spec of the ULN. If you have two pins available you can double them up. But... you have to turn them on and off at the same time. Let's say you want to use OUT6 and OUT5 as the control port. You can turn the outputs on like this:

  PINS = PINS | %01100000

To turn them off, you would do this:

  PINS = PINS &/ %01100000

In a cleanly written program you'd have a constant symbol called SOL_CTRL  that is defined as %01100000.
Jon McPhalen
EFX-TEK Hollywood Office

gadget-evilusions

Thank you. I missed that. Dang amazon typos. I appreciate the help.
Brian
Evilusions LLC
www.evilusions.com for all your pneumatic components