dirkcheap acssr for dc?

**daytimer** · 12-24-2013, 06:31 PM

Is there any reason you couldn't run 12vdc through a dirkcheap acssr instead of 120vac? As long as the current isn't too high....

**dkulp** · 12-24-2013, 06:58 PM

I don't think they would shut off without a 0 cross from the AC line.

However, I have created semi-DC ssr's from the DirkCheaps. See:

http://www.diychristmas.org/vb1/show...ighlight=dcssr

Requires a slightly modified firmware for the controller though.

**P. Short** · 12-24-2013, 07:17 PM

You can't use AC SSRs to control DC for the reason that dkulp stated.

**daytimer** · 12-24-2013, 08:08 PM

Ok... I just stared at the schematics and researched further and now I think I understand why.
I thought the on/off/dimming zero cross was only controlled by (in my case) the Ren64. But, I think I see the difference in the chips that i didn't realize before....

**MartinMueller2003** · 12-24-2013, 10:00 PM

I think you need to take a look at the info in this discussion. It will help you understand the importance of ZC. The Ren 64 does not control ZC. It detects it and reacts to it by refreshing the SSR.

http://doityourselfchristmas.com/for...des+rectifiers

**ppohlman** · 12-25-2013, 08:16 PM

Hey Dirk, is there a plan to make a DrikCheap DCSSR?

**budude** · 12-26-2013, 11:03 PM

Originally Posted by ppohlman

Hey Dirk, is there a plan to make a DrikCheap DCSSR?

I'm not clear what's being asked here? The DirkCheap SSR is cheap because it doesn't use a large TRIAC for the output but relies on the smaller TRIAC within the opto to do the work. I don't follow the context of this for DC? Are you just asking for a smaller DC output - something like the Ren48LSD does now? The biggest cost with the DCSSR is probably the MOSFET. Or are you just asking for a smaller form factor?

**fathead45** · 12-26-2013, 03:00 PM

id like a board with just a single DCSSR channel on it. i have alot of dc elements that only need 1 channel and 2 grinchs to run them.

**dkulp** · 12-26-2013, 11:40 PM

Probably a smaller form factor and hopefully cheaper DC SSR. My "hack" to the dirk cheaps uses a transistor, but that requires customer firmwares on the controllers and also doesn't provide any isolation. I was thinking of trying to experiment with sticking an opto-fet or opto-transitor. Either option would use roughly the same form factor of the DiskCheap. Obviously a much lower current that the full DC SSR (likely around .4A per channel looking at some of the specs), but for a lot of applications, that's probably enough.

**budude** · 12-27-2013, 01:47 AM

Originally Posted by dkulp

Probably a smaller form factor and hopefully cheaper DC SSR. My "hack" to the dirk cheaps uses a transistor, but that requires customer firmwares on the controllers and also doesn't provide any isolation. I was thinking of trying to experiment with sticking an opto-fet or opto-transitor. Either option would use roughly the same form factor of the DiskCheap. Obviously a much lower current that the full DC SSR (likely around .4A per channel looking at some of the specs), but for a lot of applications, that's probably enough.

I haven't seen where isolation has been that important for DC controllers - - there are 300+ Ren48LSD's out there representing over 14,000 channels and have never seen a case where the high load power somehow got back through the PIC, back through the RS485 chips and back to the PC - ever. It would be easy to just recreate the output portion of the Ren48LSD - it would still require the flipped outputs, etc as you do today if using a Renard non-SSR controller or even with an Arduino type output. Breadboard out with some cheap transistors and 470 ohm resistors - done...