PJLink problems


I'm not able to use PJLink to control my Benq WM 727 projector.
  • I've assigned a static IP address to the projector,
  • Both the projector and OpenLP seem to use this IP.
  • I can control the projector using Benqs web interface, if I visit the IP address.
  • I use the standard port 4352 inside OpenLP.
In OpenLP I get no indication at all that I'm in contact with the projector.

Any ideas?

Thanks in advance!


  • A couple of notes:
    • Both the projector and OpenLP seem to use this IP.
    If this is the case, then you need to ensure that both your computer and the projector are using different IP addresses.

    Also, you need to ensure that your projector is set up to allow PJLink connections. PJLink connection is different than your webpage connection on your projector and requires some extra setup.

    I don't have the specifications on the projector, but in the settings there should be an option to enable PJLink control - as well as an option to set PJLink password. Keep in mind that the PJLink password/pin should be different than any other password/pin that you have setup on the projector, but check with your documentation to make sure.

    Could you run OpenLP in debug mode and post your log? WARNING: running in debug mode generates a very large file, so don't actually post it here, post it to a pastebin site and post the pastebin link here.

    As soon as I can find the link, there is some help on the wiki on how to start OpenLP in debug mode as well as how to use a pastebin.

  • edited April 2017
    http://manual.openlp.org/projector.html  will show you how to tell if you are talking to your projector.

    If you don't have the Projector Manager window open (should be on the bottom-right side below the Theme Manager), you can enable the Projector Manager view by selecting View -> Projector Manager or by pressing F6.

  • edited June 2017
    Here is the debug log file at last:


    I have been in contact with the BenQ support, but they only tell me that they don't support the OpenLP software. I just wanted to know which PJLink commands the BenQ MW 727 is supposed to react to.

    Is PJLink a coherent standard which makes it easy to predict compatibility with certain projectors?

    Thanks in advance for any help!
  • edited June 2017
    Pinging the projector works fine.

    I downloaded the PJLinkTEST4PJ software and I was able to control the projector using the same IP and port as in OpenLP.

    Are you supposed to do something in OpenLP other than choose to connect to the projector to make it work? I'm using OpenLP 2.4.6 by the way.
  • Hello Funkaloss - I found the problem (Benq projector is not sending a valid standard class reply - Optoma is another projector that does this).

    Unfortunately, OpenLP 2.4 series is being replaced with OpenLP v2.6 soon and I'm not sure if there will be another update to 2.4 before then.  If you were running a Linux version of OpenLP I could probably send you an out-of-tree update to fix the issue, but since I don't have a Windows machine I'm not sure how to apply a fix.

    As noted, there will be a fix in the 2.6 release when it comes out, I'm just not sure when it will be available.
  • As far as the PJLinkTEST4PJ application, I'm not sure why it's accepting a non-standard class request (windows binary - and I don't have windows) - if it was validating the projector output it should have rejected the class version request since the BenQ and the Optoma projectors are both sending invalid replies (based on the PJLink standard).
  • Thank you for your clear answers! I will wait for 2.6 and maybe use PJLinkTEST4PJ to control the projector. Or maybe I will instead use an Ubuntu machine of ours with the fix you were talking about.
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