Bug with wait for binary input?

Robot Programming
1

Sometimes wait for binary input just gets stuck as if the signal is never sent.
I’ve got a program that loops 48 times for machine tending.

The robot sends an output to the machine to close the door(action signal true) ,
waits for left signal true
delays for a process time,
sends signal to open (action signal false)
waits for right signal true

it runs smoothly for the first 11 parts then gets stuck for no reason.
I can fix it by deleting the wait right=true statement then putting it back but the bug will happen again later, particulalry if i increase the simulation speed.

Is there a way to make the program more robust and elss likely to miss signals? I’ve tried putting a delay in between the open door output and the wait open input.
There’s also the wait trigger checkbox but I’m unsure how that changes the statement.

Thanks,

2

The WaitTrigger property listens for a signal or action event before evaluating if the input port has the specified value.

If you enable WaitTrigger and the statement gets stuck, the robot might have missed signal change event. If you disable WaitTrigger and the statement gets stuck, use the Connect Signals task pane to check the value of the port. If the value is not being changed, there might be conflicting logic OR the script in the machine is not working properly OR could be a bug.

I did a quick test and did not see anything out of ordinary using components from eCatalog. If you are experiencing this with your layout, someone in support can probably help you by looking at the layout.

image
image1920×1080 147 KB

NB: The connected signals shown in the image that are in up state is what I expect.

3

Hello,
regarding the “the robot might have missed signal change event” ,
how can I force the robot to continue listening since the signal is still green/true, but it stops at “wait signal”. How can I increase the time in which the robot continues to listen and not miss the signal?

4

In reality, missing signals should mostly be a bit of a logic problem, and the reasons can be varied, so if you can, please start a separate thread and send out your layout to get better help. (The users in this topic are no longer active)

5

Hey @BAD ,
Thank you for your reply.
Unfortunately, I won’t be able to share my layout for confidentiality reasons.

The problem that I had with multiple layouts so far,
a machine cell sends signal to loading robot, waiting for a signal back from loading robot , but the loading robot is busy with a task.

10-15 sec passes from when the signal was sent. When the loading robot finishes its previous task, it no longer listens to that signal, and the machine cell remains **waiting for a signal back

6

Hello, Have you solved your problem yet, I’m having a similar problem.

7

On the waitsignalstatement for the robot, take a look at the settings for ‘waittrigger’. If it is on on your waitsignal statements, try turning them all off

8

So the problem happens because,

  1. The robot A is waiting for the rising edge of the signal, which is the moment when the signal is triggered from another robot/cell B

  2. When the signal has been triggered from B, the robot A was occupied with something else, and thus didn’t listen for the rising edge of the signal.

  3. Robot A missed listening to the rising edge of the signal, and will wait forever.

  4. The way I solved it in “process” tab, is by using IF/ELSE for the same WaitSignal.

  5. Check image attached

It worked for me. I hope it works for you too.

image
image1540×1014 153 KB

1 Like
9

Thank you very much!!

1 Like