I had a case where the PWM had to be tweaked to a new freq for very low duty cycle vectors. We used Line and overrode way down to 1KHz and got pretty good results.
Well, then, the PWM override persists, and affects all successive layers. And the next was Fill, which cannot function at 1KHz. And Fill has no PWM override to get it back to default, nor any arbitrary value. I suggested a “dummy” layer after the 1KHz override that would be a Line mode with little or no content solely to Override to like 10KHz or 20KHz for the benefit of the following layers.
I would also say there’s a case for PWM override on all Layer types. Particularly on Image mode, the PWM being used makes a difference.
PWM on my Ruida config is flashed to 20KHz. For a light line that had to go slow through detail, we needed to specify 1KHz to get it to work, so that layer was set to Override PWM.
Next Layer was a Line + Fill, which has no PWM override. Those go fast linear speed. The Layer didn’t return to default 20KHz inside the Ruida config, it ran at 1KHz and made dashes everywhere.
I suggested he made a dummy Line layer that did a single throwaway dot, but did an Override PWM to 20KHz to stick it back. To be placed immediately after the override-to-1KHz layer.
I have done this for curiosity and think I understand what you are doing.
I think I have the same conclusion that it should not continue with the ‘override’ once it completes the ‘overridden’ layer.
Have you eliminated anything in the layers that may have been duplicated or could have any kind of effect?
I guess, I’m thinking that maybe a combination of things are giving you the ‘pattern’ that makes you think the pwm hasn’t changed…
It might be something that support might need to hear about. Most of people here don’t mess with the pwm, we don’t have the control you do. Others have brought it up, but it didn’t draw much in the way of comments.
All the documentation says is “If you have an RF Excited tube, this setting allows you to control the PWM frequency of the pulses sent to the laser, and can change the edge finish on certain materials.”
I started playing with it when I was cranking the speed on the head up.
So instead of it being a layer override it’s a machine override, until something sets it back?
This sounds like a bug, but I don’t know the workings of the Ruida. Only someone internally may know the limitations or restrictions for this. I used it to test on mine when I was running the head real fast. Just ran normal jobs after that, so maybe the pwm frequency was returned then…?
I’ve reproduced the issue on my side and have a fix in the works which should be available in the next release.
It actually turns out that it’s a problem in RDWorks as well - but it should be easy enough for us to work around it. It’s an unfortunate limitation of the Ruida firmware.
The fix has been committed.
Please note: The way it works is that if ANY layer in your job has frequency override enabled it will always send a frequency value - either the override value or the default value. This default is either whatever is set on your Ruida controller (under vendor settings) or 20kHz if it cannot connect to the laser at the time of output generation. We’ve found 20kHz is the typical default.
However, if you run a job that overrides the frequency and then one that doesn’t override in any layer, your controller will still be set to the last frequency used until the controller is restarted.
There’s unfortunately not much we can do about that - trying to send the frequency always could potentially break things for Ruida controllers that don’t support that option.
I did some testing a while back with the pwm frequency and I can see it ended up being ‘garbage’ data because of this fact. Too many things didn’t appear to ‘jive’…
Can we get a fix so PWM override is an option for grayscale and Fill?
I’ve actually discovered the override persistence bug is a useful way to change PWM. It’s awkward hack but that’s an important place for controlling PWM period. If an update removes the bug but doesn’t add the feature that would be an issue for updating since it removes the only option for layer control of PWM freq
I’ve added that option to fill and image but it might not make it into the next release which will be out very shortly and we’ve already locked it for changes. We might be able to sneak it into a 1.1 patch release if there is one.
In the meantime, you can switch to cut mode, change that value, and then back to fill and it will stick.
Though there’s nothing I can do about image right now.
