Yet another type of M291 needed, I think...

mikeabuilder

I'm working on a macro where I want to put a non-blocking M291 message on the screen that will be cancelled when another M291 is issued. My super-simple example is below

M291 S1 T0  P"This is the first message, with S=1, T=0"
echo "got here"
M291 S1 T5 P"This is the second message, with S=1, T=5"

The first M291 puts up a non-blocking message with no timeout. And I see the echo command displayed while the message is still on screen.

When I finally close the first message, the second is displayed for the requested 5 seconds.

I think the behavior happening is that the gcode execution stream is non-blocking, but the message display stream remains blocking. If that makes sense.

The behavior I expected (and would like) is for the second message to force closure of the first message.

Maybe this is a case where I should have an M292 in my macro, just before line 3?

T3P3Tony

@mikeabuilder said in Yet another type of M291 needed, I think...:

Maybe this is a case where I should have an M292 in my macro, just before line 3?

try it?

mikeabuilder

Answering my own query, but asking if I'm doing something risky.

This behaves as I want, using m292 to

M291 S1 T0  P"This is the first message, with S=1, T=0"
echo "got here"
g4 s5
m292 p0
M291 S1 T5 P"This is the second message, with S=1, T=1"

I added the M292 just before the new message.

mikeabuilder

@T3P3Tony - thanks for the vote of encouragement to give it a go. If there are not obvious issues to using the M292, I'm good to go.

T3P3Tony

@mikeabuilder not sure how it might interact with DWC cancelling a message box, thats one for @chrishamm

mikeabuilder

Now if I cancel the message box myself, I get an error when the M292 runs. I'll look for a way to add an if to see if there is an existing message box.

The object model has an array "messages" but it is not available in standalone mode.

T3P3Tony

@mikeabuilder check the OM, i think there maybe something in there. Also have a look at the 3.5 release notes as M291 behaviour has changed.

mikeabuilder

From the 3.5 Beta2 changelog:

M291 messages are now queued. When a M291 command is executed the new message is added to the end of the queue, and any non-blocking messages already in the queue have their timeouts reduced to 1 second. If the queue is already full then the oldest non-blocking message is cancelled, or if there are no non-blocking messages in the queue, the oldest message is cancelled. The queue length is currently 8 messages.

In my test initial three line macro, it does not seem like the first non-blocking message is getting it's timeout reduced to 1. I tried changing the timeout on the first message to T=9999, and the timeout does get reduced to 1, so I have my solution. I'll just set the first timeout to a very long time. Maybe a non-blocking timeout t=0 is a special case for the timeout length reduction thing.

OwenD

@mikeabuilder
You can check if the messagebox array is null. If it's not null, then a message box is being displayed.

if state.messageBox!=null
   M292 ; cancel message box