Intermittent laser glitch

I recently acquired a Laserworld DS2000RGB and am spending some time getting my head around the nuances and limitations of its display abilities. At the moment, I’m experiencing an intermittent badness in developing some test patterns.

Symptom

Most of the time, things are fine, but occasionally the laser completely freaks out, then shuts off light for several seconds before becoming responsive again.
In words: The servos go absolutely wild, drawing random patterns across the scan range. The RGB modulation also looks like it bugs out randomly, but mostly the trace stays shades of white.
Here’s a video showing a simple test pattern, which has a small glitch (misplaced line) a few seconds before the misbehaviour https://www.youtube.com/shorts/jMvvuJFJ9W4
Once this occurs, the laser remains off for a few seconds (5+) and eventually switches back on, showing the expected pattern.

Occurence

  • I have not observed this behaviour when using the proprietary ShowNet admin tool to display test patterns.
  • This occurs in the network view, whether or not I’m messing about with the contents, although I suspect it’s less frequent when it’s running ‘hands off’ without me messing around with the network.
  • I tried reducing the frame rate to 40fps but this did not resolve the issue. In fact, the behaviour occurs even at times when the FPS is exactly on target; furthermore, if I add hog CHOPs until the framerate tanks, the laser continues to draw
  • Sometimes (perhaps more concerning) the laser device CHOP raises a warning ‘Failed to open device’ after this occurs, and I need to restart TD in order to re-establish control over the device.

Setup

The laser is being controlled from my laptop which is connected directly via ethernet cable. I am unsure whether it’s streaming ILDA to the interface or whether the laser device CHOP has built-in compatibility with the proprietary ShowNet protocol (and I would very much like to dig deeper into how the laser ops work so I can get the best performance from this device; the documentation I’ve found so far is not especially detailed).

Anyone else had a similar experience, ideas about the cause or further tests?

Hey @groundhogstate,

thanks for sharing this detailed description, could you additionally share with us your test file so we can try to replicate the behavior here?
Could you also list your computer’s hardware and OS as well as TouchDesigner version you are currently using for this?

cheers
Markus

Here’s the file, and system information. TD version 2023.11290.
Screenshot 2024-03-19 150725

laser_interface.toe (8.9 KB)

1 Like

Hi @groundhogstate,

thank you for sending this, we are looking at the issue.

cheers
Markus

Thanks, how’re you going with it? Did you manage to reproduce the behaviour?

I looked at the ethernet packets being sent by using wireshark. In the case of the ShowNet admin tool, there are some occasional re-registrations, but otherwise things run smoothly. When using TD, the packet history shows more frequent re-registrations, and then some anomalous behaviour which I think, but haven’t timed precisely, coincides with the main features of the symptom. Some screenshots below in case they are helpful.

Would there be any other tests you would recommend in the meantime?

Screenshots

Running ShowNew admin tool

There is a handful of these strewn across a couple minutes of uptime

Normal running looks like this, which is pretty similar to the normal operation of the TD interface.

There are a couple of places where someone drops out

But no other suspicious behaviour after several mins of runtime.

Using TouchDesigner

On first connection, the exchange is more or less the same as when using the admin software.
This is followed by a few other membership reports or registrations as well; they could more frequent though. Eventually it gives up, and there are some anomalous packets; in particular, they are just about a carbon copy to the packets exchanged when the laser is switched on. NB I ran this test first, chronologically. I’ve sent some further screenshots to your inbox @snaut

We haven’t been able to reproduce the issue yet but we have reached out to LaserWorld to get their help with reproducing/solving. I do at least recommend updating to the latest TouchDesigner official build which uses the most recent ShowNET SDK version (1.3). 2023.11290 is still on an older version, although I can’t reproduce in either build so it’s unlikely to be the fix.

That’s interesting to know about your differences in packet activity between TouchDesigner and the ShowNET admin tool. We don’t have direct control over that aspect since it’s all handled by the SDK, however it may point to a misconfiguration on our end. We’ll continue to look into it.

Heya, thanks for the tips.

I’ve upgraded to the latest TD and in fact due to another issue performed an OS reset, which hopefully eliminated a lot of variables. However the bug still occurs. Somewhat worryingly, I did start up with a fresh file on a friend’s Macbook (as above, I’m using Windows) - the error syndrome still occurs. At this point I’m concerned that the issue could be in the laser interface itself, but, as I noted above, the problem has not arisen when using the ShowNET admin tool.

Just to be sure, are there any other configuration details that might have been overlooked? For example, I could only establish a connection via ShowNET with my laptop and the laser set to static IP configuration; LaserWorld also warn about possible issues with WiFi being concurrently on, but I’ve got that set up so it uses a different address space to the laser. Anything different on your end or that you’d recommend fiddling with?

I haven’t purchased a license for other LaserWorld software so that’s not feasible test immediately, but I think it could be worth trying other software in the interim.

Oh another thing that might be relevant, @eric.b / @snaut - the laser in question is actually a DS2000 Mk3. If you’re using another Laserworld product to test, perhaps you have a newer generation? I have no idea whether their interface design changed between mk3 and mk4, but it might be a consideration.

A potential breakthrough: I’ve heard from another user who had a similar issue while using an Etherdream interface. However, in their case, the error state occurred using windows, but not a Macbook; It was alleviated after switching from an AMD 5950x to an intel 14900k. Strangely enough, as earlier in the thread, I’m using an Intel.

Further, I’ve since tested using a Mk4 and the situation is unchanged.

I’m testing with a DS-1000RGB MK3 so there doesn’t seem to be an issue between MK3 and MK4.

If another user experiences the same issue using EtherDream with the ShowNET laser then that means it’s unlikely to be a problem with the ShowNET control API. It could be that the points generated with the Laser CHOP are causing the problem – do you only experience the issue with a specific Laser CHOP input, or others as well? Does lowering the output sample rate have any impact on reproduction frequency?