Siemens FB dev mon/mod values in VAT for debug... and other FB dev questions.

[Nick Birke]

I want to protect motor against excessive heating due to motor stall,I want to use the motion sensor to detect the motion of the motor rotation when it stall i will use the output signal from the sensor and program them so that it will activate the time delay timer in PLC to acumulate up to 60000msec the incorporate it with the stop circuit of the motor to disconnect it from the power supply to avoid overheating of the motor windings. Please help me how to program those voltage pulse from the sensor to perform that operation

 

[Nick Birke]

Why do you refuse to try out what has been shown to you?

Wow rough.

Anyway... what has been showed and explained does not exactly match what I am doing. However I think it will help. I don't have a PLC at home so I couldn't try out what I think I need to do... but I think I get it. I will keep you posted.

Thanks for all the replies. This board is great.

 

[TurpoUrpo]

No, not rough. Straightforward.

You can't make FB that is usable as multi-instance if you need other FB's in that FB and you do not use them like LD demonstrated. That parent FB can then be either used same way or called with its own IDB. In latter case if more than one call is needed, then you need to assign new IDB with every call.

 

[Nick Birke]

No, not rough. Straightforward.

You can't make FB that is usable as multi-instance if you need other FB's in that FB and you do not use them like LD demonstrated. That parent FB can then be either used same way or called with its own IDB. In latter case if more than one call is needed, then you need to assign new IDB with every call.

Ok... so anyway... in my FB- FB78, I have created a STAT called STIMER of type SFB4. And replaced the old SFB block with STIMER. This seems to have changed the behavior somewhat (I should have taken better notes on what I observed before.)

It could be my LAD... but it worked with a single instance before... I can try studying that... but I did thing of on thing I need to address...

I definitely "broke" some things with respect to the way FB78 works. The old SFB4 (actually on the rung assigned to DB4) I needed to essentially manually reset it by assigning new values in DB4... I could not get the done bit to go away, or get SFB4's internal status to update back to zero (apparently turning the power off is not enough (EN/IN inputs of SFB4) to get the Q (done) to reset and timer state to go back to (well I set it to 0) and that seemed to to work fine for me. How do I fix this? Is there a way to address/see the DB that is associated with the STAT "STIMER" of type SFB4? Or how am I supposed to reset it.

 

[L D[AR2P#0.0]]

May be obvious, but did you regenerate the instance DB associated with the call to FB78 ?

 

[Nick Birke]

May be obvious, but did you regenerate the instance DB associated with the call to FB78 ?

I think so... by the way I got the above solved... I can just reset STIMER.Q and STIMER.ET.

Actually regarding regenerating those databases... in the past when I would make changes to the interfaces... it would prompt me to regen them... it didn't do that this time (I replaced the calls to FB78 on the rung, put the same DB numbers in, and it didn't complain. I'll have to figure out how to initiate a regeneration manually... in the meantime I'll just change the DB numbers... as they will be regenerated as they are created... I'll keep you posted.

 

[Nick Birke]

Ok... I think I have this down where I really need to comb through my FB... I am still having inconsistent behavior based on whether or not there is just on instance of the FB element in the program or more than one.

 

[TurpoUrpo]

If you put it on library and post here, we can look what is the problem.

 

[Nick Birke]

One step forward... two back...

May be obvious, but did you regenerate the instance DB associated with the call to FB78 ?

If you put it on library and post here, we can look what is the problem.

I could do that... but this is very strange... I took one of the FB78s out of the OB1... just to make sure that it is working right with just one of them. Inside the FB I have created SFB4 in the stat table as DT SFB4 which displays as TON... based on everyones instruction.

Now the timer inside FB78, #STIMER... will not count up when energized... I know it is very hard to say what is going on without seeing all the rungs... but there is nothing in the program to explain this. See image.

 

[L D[AR2P#0.0]]

You have got to the stage where images are useless. Create a library and copy your blocks to the library. Archive the library then attach to your post.

 

[L D[AR2P#0.0]]

Here is an empty library - download it, retrieve it using Simatic manager, copy your blocks into it and then archive/attach to post.

 

[Nick Birke]

I looked at some other things that used to work and its almost like the rungs arent even really working even though they have energy. I am thinking about making another FC with just SFB4 in the STAT, and just putting the timer on a rung with contast presets and see if it works.

 

[TurpoUrpo]

You would do yourself a favor by posting the library to us. We cant help you if you dont let us.

 

[L D[AR2P#0.0]]

For starters, Timer logic should be fed to the IN pin, EN should be true all the time.

 

[Nick Birke]

Here is an empty library - download it, retrieve it using Simatic manager, copy your blocks into it and then archive/attach to post.

Ok... I just archived the whole project. FB78 is not perfect but it was working. There are probably some things that appear redundant... it does need to be cleaned up... this has been a work in progress... this project also has a lot of stuff in it that was created along the way that are not used... All that I think needs to be reviewed is OB1, FB78, AND DB12 (used in OB1 to create an instance of FB78.

Thanks for the babysitting. This is probably something really dumb.