Jan Steen Nielsen FB121 won't work...

[nightline]

Gents,

I've a machine with a S7 313C PLC, and have to control a temperature. At this moment it's done by some timers, with a lot of temperature alarms.
So I found a sample program from Jan Steen Nielsen from Danmark, who programmed a FB121 Pid controller.
I've copy passed the FB121 with the DB121 instance block in the controller.
I've put the FB121 in FC70, and created the Data in DB70.
If I monitor DB121, I see a lot of parameters changing, except the output variable.

Has anyone any idea, what I do wrong?
Or is more information needed?

Thanks in advance!

Jack

 

[KalleOlsen]

Never used or even heard about your blocks.

Any particular reason you don't use the FBs from Siemens' standard control library? If I remember correctly there is a FB58 foreseen for temp control.

Kalle

 

[nightline]

Hi Kalle,

It's probably my knowledge about programming Siemens S7, but I've tried FB58 also, but I've not found a good manual for this FB how to program it, and to use it.

Jack

 

[KalleOlsen]

There are many users of FB58 and FB41 on this forum, so I think it is much easier to get help and advice on those FBs.


In this old thread I posted a screenshot of a FB58 call. It is done in CFC, but if you don't use CFC you can still use the settings to make the controller start working. There's some further explanation in later posts. It will of course need additional tuning to fit to your process' parameters.

http://www.plctalk.net/qanda/showthread.php?t=55913

Kalle

 

[nightline]

Okay, I've a FB58 with DB58 in my program FC70.
And an OB35 with a call for DB58.
The FB58 will not work, and I don't know why, I've read several manuals, and threads, but can't find the problem...

 

[RMA]

And an OB35 with a call for DB58.

Is that a Typo and you really meant you call FB58 in OB35?

Also what do you mean by "will not work"?

It would help if you could post a PDF of OB35 showing how you've parameterised FB58.

 

[nightline]

Is that a Typo and you really meant you call FB58 in OB35?

Also what do you mean by "will not work"?

It would help if you could post a PDF of OB35 showing how you've parameterised FB58.

FB58 is programmed in FC70, in OB35 is a call for FB58/DB58

 

[KalleOlsen]

...and the online values in DB58, please.

Kalle

 

[nightline]

...and the online values in DB58, please.

Kalle

See the attachment..

 

[Lancie1]

What is "DATA VERWARMEN"?

 

[nightline]

"DATA VERWARMEN" is DB70 is a DB with all parameters for the heating sections.
Verwarmen is dutch for heating..

 

[KalleOlsen]

See the attachment..

If you select View/Data View and go online, you will reveal all the values in the DB58.

Kalle

 

[JRW]

Keep it simple
If you put the loop in manual mode and give it a manual value say 50.0
Do you get an output?

 

[nightline]

If you select View/Data View and go online, you will reveal all the values in the DB58.

Kalle

See the attachment...

Keep it simple
If you put the loop in manual mode and give it a manual value say 50.0
Do you get an output?

Yes, I get an output, a very high value..

 

[JRW]

with MAN_ON = 1
and MAN at 50.0
do you get a 50.0 at LMN ?
also do you get a 1 at QC_ACT ?