Upper limit of printers from 1 windows machine?

thatguy

I'm looking at the metrics of rapsberry pis (or other solutions...) vs windows pc. It seems the computing power of a 'real pc' is significantly greater once you look at purchasing multiple raspberry pis.

We're looking at something like 10-15 printers, all with webcams connected to a single NUC style windows computer, using USB 3.1 to allow bandwidth, and hubs to provide the extra ports. Is this possible / advisable?

Repetier

I would install linux on the pc. Especially W10 likes to force install updates and reboot without giving you a chance sooner or later. You can delay such updates but not prevent. With so many printers you are most likely printing at some when it happens. And since speed is same use linux if there is no other reason. Then you can also use our mjpg_streamer solution for the webcams.

The number of printer is that really a limit since the communication with printers is small. Here the problem is having enough usb port, reliable communication since some usb cables will get longer to reach them all making it more problematic. So problem is electronic stability with all devices attached. When they are of good quality it is possible. Know at least users with 10 printers on a windows machine.

Webcams are the one eating bandwidth. Not sure how USB 3.1 can help here since printers don't use it and webcams not so far. But I think having a few active usb hubs (or disable 5v line on usb connectors so printers can not draw current) to have shorter lines to printer cluster would help. Then you have usb2 to the printers/webcams and from hub hopefully upgraded to 3.1 speed also I'm not so much in this topic to guarantee this.

Last thing is to decide if it is wise in your situation to have so much printers on one device or instance. With some hacking you can also run multiple instances on one pc. For our demo server we have for example 12 running in parallel so every 10 minutes we restart one to reset to start condition in case users deleted all files or similar. Why? Well if you need to restart server due to update or some problems (electronic problems or other problems) you try to solve you need to wait for all to finish. The longer a print is on average the less printers I would connect per instance. With our Repetier-Server Monitor you can still control all from one interface.

thatguy

Interesting. Do you know how your other customers running multiple printers on Windows handle the update situation?

What is the difference between using webcams on Windows vs linux?

Hmm, I was thinking that 3.1 gives a higher bandwidth to the hub, which could then allow more webcams to be used, but maybe the protocol doesn't work like that?

How does one run multiple instances on 1 PC? I like this advice in principle, it makes a lot of sense.

I don't suppose you'd be able to connect me to a user/s that are currently doing what we want to do? It sounds like it might allow us to avoid a lot of pitfalls quickly.

Repetier

Webcam difference is that for linux we have mjpg_streamer which can be configured from server with some setup and is free. For windows the only software I know handling multiple webcams as mjpg streams is https://blueirissoftware.com/ which is not free.

The problem with usb is that the slowest defines the speed. If you have a usb 1 device connected you need that speed or it will not understand anything. So question is can a hub speak usb 2 to one side and speed up to 3.1 on the other side. Or is it syncing speed.

You can enter how long to delay updates in windows. Maximum is 180 days I think. So if you then e.g. install manually updates every x month you might be safe. Not sure if windows can force emergency updates faster, but that is what I'd try to do.

Multiple instances on linux is quite easy. The initial config file is a xml that tells where storage directory is and which port to use. The trick is to have multiple such config files and start them all. In linux you just copy the Repetier-Server.service file in /lib/systemd/system and adjust the config file and it will start. For windows I actually don't know how to do it right. We call it on setup so it registers as service but it will use default config file relative to executeable then. So you would need to install it into different directories manually from the original installation. On updates you need to do the same. Hacking windows is unfortunately not so easy as windows.

thatguy

Thanks - I'll look into that. It is not cheap!

Interesting - I'll look into the USB hub one. I suspect you may be right, as I don't think most hubs have a processor built in which it seems would be required. So then you need the computer to have as many USB ports as you need? or do the internal buses cause the same problem? Do you know how your other customers are accomplishing their multiple instances with webcams?

180 days and a calendar reminder will work ok for updates. Not perfect, but a workable workaround.

In Windows I think you could use different exe startup parameters to accomplish the config file load.

Repetier

USB 3.1 is not really required. The printe rit self have no high data volume so mainly webcam counts. On pc every output has normally it's own chip and processor connection so if you have multiple hubs e.g. 3 with 8 usb ports you can put on each one 4 printer and 4 webcams. Now the trick is that webcams should send compressed mjpg data in the requested resolution. Then you can control bandwidth usage quite easily. Can't say how this works on windows but mjpg_streamer uses this feature if available and all better webcams have hardware mjpg support.

You are right. You can make a simple script that is run as admin to start with different configs. The default config/server gets started like this over a script:
"C:\Program Files (x86)\Repetier-Server\bin\RepetierServer.exe" /c "C:\Program Files (x86)\Repetier-Server\bin\RepetierServer.xml"And as said you just need multiple xml files where you change data directory and port.

thatguy

Would something like this work to replace blueiris? https://www.contaware.com/contacam.html

Do you have a list of recommended webcams?

Repetier

No, don't think that software works. We need software that outputs images and mjpg streams over web. It is not the fact that a software can view the cams. And that is the main problem - most just concentrate on viewing them somehow.

We have no recommended webcam list. Any webcam supported by OS and outputting mjpg streams should do. We have several different logitech webcams and all work fine.

thatguy

I haven't tried it yet, but

https://www.contaware.com/contacam.html in the new version features has:

Re-stream a video source through the web server, see this FAQ entry

This is the FAQ entry link:

https://www.contaware.com/manual-faqs/21-05-contacam-networking/90-web-server-url-of-camera-feed.html

So maybe possible?

Repetier

Could work. At leat it offers a stream. But I did not see which format the stream has. Must be mjpg.
Side note - next server release can also use mjpg streams to make a image snapshot, just in case your solution has no snapshot url.

From a comment on forum last days I also take that you can start yawcam several times for multiple webcams.