PJLINK feedback

[William Childs]

Howdy.

Using PJLINBKcommands on the network with Qlab, and it workd like a chanp!

I want to add some feedback for the operator.  Is there an easy way to get feedback from the projector to (like) display on a Cart button?  I'm looking for shutter on/off, and power on/off so the operator can confirm in the blind....

Bill

[utku kara]

I also use Pjlink it works great.

For check is it on/off you can use cue color.  put a second color to cue . When run the cue color will change with second one.  

Mobile

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William Childs <wdchi...@gmail.com> şunları yazdı (7 Haz 2026 22:23):

Howdy.

Using PJLINBKcommands on the network with Qlab, and it workd like a chanp!

I want to add some feedback for the operator.  Is there an easy way to get feedback from the projector to (like) display on a Cart button?  I'm looking for shutter on/off, and power on/off so the operator can confirm in the blind....

Bill

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[Paul]

You can find the PJ Link protocol specification at https://pjlink.jbmia.or.jp/english/data_cl2/PJLink_5-1.pdf 

On page 25 you can find the AV Mute Status query message, which will give feed back on the stat of the shutter.

Unfortunately AFAIK there is no way for QLab to be able to read the response from the projector (no ability to add a handler for message etc).

So you would need some external software to process the response and then send a signal to QLab (like OSC to run a cue).

But basically, providing the control position can see the stage, I would advise the operator to look at the projection screen and check that the projector is on and the shutter is open. This is much more reliable! You should always run a video rig check  before each show.

Note also you should always turn on your projector before starting QLab, so the utility of a feedback function for power on is dubious.

[Sam Kusnetz]

I know many shows, including some on Broadway, that have a preshow cue that’s only obvious if you know where to look. A single red pixel in one corner, or a thin line along one edge. This lets the crew have some confidence that everything is working even after the audience is in and it’s too late to check in a more obvious way.

sk

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[William Childs]

thanks, all-

this is about what I figured- the communication is one-way...

Good reminder about the inconspicuous "tell" for the operator.  We're showing a preshow sponsor loop on the main screen, and want to fade and shutoff the video projector prior to the (film) projector taking over.  Just blacking it out, and shutting down in the blind is nerve-wracking without some kind of feedback.  other than that, the built in pjlink interface works perfectly!

Bill

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[Paul]

You could do this via Companion although it would be a multistage process. In Companion make a Connection using PJ Link Module. Then in the Triggers for Companion, you can monitor the AV Mute status being 'on' or 'off' (you need two different triggers). You will also need the generic OSC module configured to send to your QLab machine on (default) UDP port 53000. 

Then in the Action of the trigger you can use OSC to send message to change the colour of a Cue Cart cue (if you QLab cue cart cue was numbered 'ScOpen')

/cue/ScStatus/colorName Red

/cue/ScStatus/colorName Green

(note you can't use the QLabfb module in Companion for this as the only cue colour option in the module seems to be for the selected cue, and here you would want to specify the cue directly).

You could use this same cue cart button in QLab to to control the shutter directly using PJ Link but it would get its feed back via Companion. I wouldn't regard this as a particularly robust solution, compared with say, sticking your head into the auditorium to make sure the pre-show sponsor logo has gone, but may be useful in some cases.