Multi Instance FB's

I just started playing around with Multi instance FB's.

And I don't find the help file very helpful.

Quick question.

I have 3 conveyors, used multiple instance FB's.

Now when I right click and goto monitor is that cycling thru all 3 conveyors?

And if I goto monotiro with called path is that just displaying the 1 specific instance I am worried about?

Thanks,

Hi
Has each FB got its own DB? Or are three 3 FB's in turn buried inside a master FB

Generally people would have a dedicated DB for each

Best thing to do is create a VAT for each conveyor

I had that problem yesterday

JOLTRON said:

I just started playing around with Multi instance FB's.

And I don't find the help file very helpful.

Quick question.

I have 3 conveyors, used multiple instance FB's.

Now when I right click and goto monitor is that cycling thru all 3 conveyors?

And if I goto monotiro with called path is that just displaying the 1 specific instance I am worried about?

Thanks,

Click to expand...

I had two multi instance FB talking to motion controllers. The only difference was the Profibus Addr ( LADDR ). I found that I had to tempporarily disable the first FB by putting an open coil in front of the first FB if I wanted to see the second FB updates.

Hopefully someone else has a better idea but I run into this problem even when doing assembly or C programming. If I have 8 instances of axes and I want to debug the 6th instance then I usually put a check at the top of the code to immediately return if the current instance is the one I am interested in. Just remember to remove the debug code.

cjd, all 3 datablocks are contained in the master FB's stat area.

Peter, thats what I figured I would have to do. I just thought I was on to something when I found the "Monitor with called path" option. It seems to monitor the instance that I'm interested in but will have to play with it some more when I get back to my other office.

Thanks,

JOLTRON said:

I just thought I was on to something when I found the "Monitor with called path" option.

Click to expand...

I saw and thought the same thing but I tried it and it didn't work. I think my S7 hates me.

Peter Nachtwey said:

I think my S7 hates me.

Click to expand...

Your not alone

If your call structure is FB1->FB2, FB3->FB2, FB4->FB2 then you can select debug mode and then use call environment to specify which instance to monitor.

If your call structure is FB1->FB2,FB2,FB2 then the S7 Connection isn't clever enough to tell the difference between the calls to FB2. In this case, the only way to confidently monitor FB2 is to make sure that only one instance is being executed. For diagnostic purposes I sometimes copy a block and then change one of the calls to the new block so that it can be monitored.

Nick