Connect IRC5 to PLC and exchange data in real time...what am I missing?

[foilman8]

 
I am a 30-year PLC programmer, working with a 10-year robot programmer.
We are really stuck, attempting to marry a PLC (Rockwell) to an IRC5/IRB360.
The data connection is fieldbus (DeviceNet).
What appears to be happening is that the data is not properly in time with each end.
The robot appears to be answering questions about future events sometimes, and present events sometimes.
As you might expect, this drives the PLC nuts.

So, the question is:
How can data exchange with an external device be synchronized in real time, so as to avoid all this 'future thinking' that the ABB seems to be doing?  We simply can't be the first people to do this!

Oh, BTW, this is a highspeed picking application, so milliseconds matter, and are the reason we need to exchange data in the first place.

Thanks in advance.

[Fabian Munoz]

Hi:

I dont know how or what kind of data you're sending BUT is this transfering done while the robot is moving ?

You know robots are smarter now and they read ahead, can you as a test run the robot slower and see what happens OR make the zone points FINE so the robot has to pay more attention to the encoder than the communication.

I dont know if ABB has a parameter to force the robot to process one step at a time

That same issue happened to me before and the way I fixed it (your robot programmer is going to hate me) is to read twice and compare, basically loop the communication until robot confirms itself.

I hate milliseconds !!!!!

[luetin]

Yeah, try fine points like Somar said and if that works you can exchange those to MoveLSync/MoveJSync to speed things up.
I usually put communication tasks in a background task as well if doing pick and place applications.

If those suggestions don't work I think we need to see some code to help further.

[RobotBoy]

It might be a good idea to also post this question in the ABB RobotStudio forum. That forum also deals with other ABB Software issues like RobotWare & PickMaster. I know the ABB experts monitor this one quite closely.

You need the Robot Controller/RobotWare section at the link below
http://www.robotstudio.com/forum/default.asp

[tony gast]

I had an IRC5 talking to 8 PLCs and had timing issues that I only was able to resolve by using "ECHO" loops to send info ....... DO UNTIL the echo matched the sent. also watch the cpu usage while looping....some times this made the IRC unstable.....

[Fabian Munoz]

This is interesting, everybody is trying to make very fast motherboards and We, the robots programmers, are doing the imposible to slow them down using software

[foilman8]

Actually, the hardest part is not having a real-time tool to datalog variables.
The robot guy wrote a 'write raw data to a line of text in a text file' function, and I used a Trend feature in the PLC...and then we played like real geeks, comparing our excel spreadsheets.
It actually worked, but is a little funky, since the PLC time stamp is in milliseconds, and the IRC 5 is in microseconds.