PWMSlope Behavior

Related to the development libraries, released by Curt Binder
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rimai
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Joined: Fri Mar 18, 2011 6:47 pm

Re: PWMSlope Behavior

Post by rimai »

nanotrevor is having a hard time with pucks.
In my opinion, the way the pucks were designed is wrong, but that's just me. They may think the same thing of my controller design.
The issue he's having is exactly because of the - from RA connecting to LED string directly. The LED string is a high side of the driver and creates disturbunces and noise that is carried to the RA, causing it to lock-up or present weird behaviors.
I'm working with him on trying to isolate the 2 sides with opto-isolators, which should take care of his noise problem.
Roberto.
icecool2
Posts: 62
Joined: Tue Jul 19, 2011 3:12 pm

Re: PWMSlope Behavior

Post by icecool2 »

Well, you can mark Recom drivers as compatible with your design. I do have some isolation built into my PCB, but nothing unusual that you wouldn't expect any novice to design in.
NirvanaandTool
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Re: PWMSlope Behavior

Post by NirvanaandTool »

rimai wrote:nanotrevor is having a hard time with pucks.
In my opinion, the way the pucks were designed is wrong, but that's just me. They may think the same thing of my controller design.
The issue he's having is exactly because of the - from RA connecting to LED string directly. The LED string is a high side of the driver and creates disturbunces and noise that is carried to the RA, causing it to lock-up or present weird behaviors.
I'm working with him on trying to isolate the 2 sides with opto-isolators, which should take care of his noise problem.
Hmm gotcha. Would it be better to build that circuit they describe on the wiring diagram in order to have them run in a non-inverted state?
-Ralph
DVRC's Mantis Shrimp Addict
15g display/7.5g sump - G. Chiragra & G. Viridis | 35g build in progress - future O. Scyllarus
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PWMSlope Behavior

Post by rimai »

I don't think that would solve the issue. The biggest problem is connecting the LED- to RA ground.
Roberto.
NanoTrevor
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Joined: Thu Jun 02, 2011 1:58 pm

Re: PWMSlope Behavior

Post by NanoTrevor »

rimai wrote:I don't think that would solve the issue. The biggest problem is connecting the LED- to RA ground.
if its wired with a transistor there is no - led connection. i tried it, i have the parts but didn't have any luck, i wired the other way cause it was quick and worked with the code inversion...but this would prob solve all probs to wire this way
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rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PWMSlope Behavior

Post by rimai »

The picutre above would never work the way it is.
The signal LO/HI needs a ground reference, which isn't represented in the design.
Roberto.
NanoTrevor
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Joined: Thu Jun 02, 2011 1:58 pm

Re: PWMSlope Behavior

Post by NanoTrevor »

rimai wrote:The picutre above would never work the way it is.
The signal LO/HI needs a ground reference, which isn't represented in the design.
hmm, prob why it didn't work for me, i thought i wired it wrong somehow.
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PWMSlope Behavior

Post by rimai »

icecool2 wrote:Well, you can mark Recom drivers as compatible with your design. I do have some isolation built into my PCB, but nothing unusual that you wouldn't expect any novice to design in.
Can you post your schematics?
I'm interested to know how you connected the RA GND to your drivers.
I'm starting to think I originally led nanotrevor into the wrong path :(
Roberto.
NanoTrevor
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Re: PWMSlope Behavior

Post by NanoTrevor »

rimai wrote:
icecool2 wrote:Well, you can mark Recom drivers as compatible with your design. I do have some isolation built into my PCB, but nothing unusual that you wouldn't expect any novice to design in.
Can you post your schematics?
I'm interested to know how you connected the RA GND to your drivers.
I'm starting to think I originally led nanotrevor into the wrong path :(
:(
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: PWMSlope Behavior

Post by rimai »

Sorry Trevor...
I've been reading lots of places that people just have these problems with the buckpucks. Not just you.
The solution always seems to be optoisolation, like we've been working on.
But, there was a couple of places where they mention connecting the Vin- to ground, instead of LED- to ground.
I don't know if that would make any difference on the whole issue, but it would be worth trying.
Roberto.
NanoTrevor
Posts: 69
Joined: Thu Jun 02, 2011 1:58 pm

Re: PWMSlope Behavior

Post by NanoTrevor »

rimai wrote:Sorry Trevor...
I've been reading lots of places that people just have these problems with the buckpucks. Not just you.
The solution always seems to be optoisolation, like we've been working on.
But, there was a couple of places where they mention connecting the Vin- to ground, instead of LED- to ground.
I don't know if that would make any difference on the whole issue, but it would be worth trying.
i actually tried that on another arduino based controller i had tried and it didn't work connecting to vin - instead of led -
icecool2
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Joined: Tue Jul 19, 2011 3:12 pm

Re: PWMSlope Behavior

Post by icecool2 »

Sorry, I don't have a schematic handy. I have a current limiting resistor on the signal line from the RA to the driver. On the driver side, I have the digital ground separated from the analog ground and joined with a small bridge. There is also a weak pull up on the driver as well. I have the GND from the RA run to the digital ground of the drivers. The analog grounds are connected on the AC side between the RA and the power supplies for my drivers.
NirvanaandTool
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Re: PWMSlope Behavior

Post by NirvanaandTool »

Yikes. Sounds like problems all over.
Maybe I'll skip trying to get the Buckpucks to run off the PWM and get some RA moonlights instead.
-Ralph
DVRC's Mantis Shrimp Addict
15g display/7.5g sump - G. Chiragra & G. Viridis | 35g build in progress - future O. Scyllarus
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