Problem with instructions in-advance execution

[Sergei Troizky]

I am currently programming a case packing handling application on NX100.
The job contains sequence of consecutive motions, most without stops in between them (PL>0).
There are two checkpoints: for product presence before last movement to pickup, and for case presence before inserting product into case. In lack of the corresponding input signal, the job will stop motion and wait for it. Normally, signal is already active on the robot arrival to checkpoint.
The problem is that the job executes several instructions in-advance, which performs
the mentioned checks long before robot arrival to the checkpoints.
This causes unnecessary momentary stops in the checkpoints, which increases the cycle time from 3.5 sec (test job with no mentioned checks) to unacceptable 4.2 sec.
I tried ENWAIT in attempt to delay the checks until robot arrives to checkpoint proximity, but this does not work.
Is there any other solution? Any suggestions will be highly appreciated.

[Fabian Munoz]

Sergei:

I was just talking about this "reading ahead issue" on another thread. I don't know if the developers of robot software actually come down to the real world and do some programming.

On one of the jobs that I did and I had exactly what you described and this is what I did. BTW it all depends on the application and speeds and blah blah blah.

The main thing here is to delay the processing time

One more thing, Are you doing all this with a PLC or directly to robot I/O ?

1) Write the question for part present or any handshake on a different .jbi. Basically you are delaying the processor when CALLing a routine

2) Write some kind of a loop where you confirm your I/O, and use a TIMER=0.01

3) I know you dont want to use PL=0 because that kills your cycle time. Use a TIMER=0.01. You'll see the robot pause but believe me, is less than a PL=0

Do this test. Write a program, say 10 points using pl=0 and run it, then use the same points without PL and add the timer after every point. You'll see

4)I'm guessing you are using P vars, Using your Pxxx for pick up, make a point before Pxxx - 20 mm. Then ask your questions between Pxxx-20 and Pxxx

Good luck

I know exactly what you are going through   

5)Call Motoman, there is a way to get rid of the read ahead but that might cost you $$$$