Jan Steen Nielsen FB121 won't work...

[nightline]

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 ?

Sometimes:
First time: high value at LMN
Second time: 50 at LMN
Third time: 0 at LMN

It has run for a while, when I changed the PV, the LMN act's like it should, but after a while it stopped, and won't run anymore...

I don't know if it matters, but Com_RST is also high...

 

[JRW]

I just wrote a quick sample and it works
You want it?

 

[nightline]

Yes, please!!
Can you drop it here?

 

[JRW]

I will try
COM_RST should not be toggled

 

[JRW]

Retrieve in Step7

 

[JRW]

Here you go
Its very basic- but it works

 

[KalleOlsen]

See the attachment...

Had a quick look at the online values of DB58 (the first part).

If you check it, you'll see that many of the real values are of wrong format. Start checking out the formatting first.

Kalle

 

[nightline]

Here you go
Its very basic- but it works

JRW, I've tried your program, and it seems to work fine.
Next Monday I'll try to import your program in the machine program.
I need 3- PID loops for this machine, can I simple copy the FB / DB 3 times, and rename the variables?

@Kalle, it needs REAL's so I created REAL's....or...

 

[JRW]

One FB58 and 3 instance data blocks
Are you using step outputs (bool) or a continuous output (analog)?

 

[KalleOlsen]

JRW, I've tried your program, and it seems to work fine.
Next Monday I'll try to import your program in the machine program.
I need 3- PID loops for this machine, can I simple copy the FB / DB 3 times, and rename the variables?

@Kalle, it needs REAL's so I created REAL's....or...

DB100.DBD70 is connected to DB58.PV_IN, but according to the DB58 online snapshot it cannot be interpreted as a real number. How do you treat the DB100.DBD70? (How is the code behind?)



Kalle

 

[nightline]

One FB58 and 3 instance data blocks
Are you using step outputs (bool) or a continuous output (analog)?

We're using analog output.

DB100.DBD70 is connected to DB58.PV_IN, but according to the DB58 online snapshot it cannot be interpreted as a real number. How do you treat the DB100.DBD70? (How is the code behind?)



Kalle

I'm sorry, but I've no idea what mean..

 

[nightline]

JRW, I've dropped your program in the machine program, and it works.
But I see no Feed Forward, is there more to program? As you said, you're program is very basic. What can I do to make it more fancy?

 

[nightline]

Well, I've programmed everything in the machine, and.... it won't work again.
But after some phone calls with the Siemens Tech Support, we found out what Kalle allready mentioned, the value's are wrong displayed.
So what was done in the machine PLC, the analog input was moved to an integer, and the integer to a real....And this will not work in Siemens....!!! So I had to convert the integer to a double integer, and this one to a real.
And now everything is running...

Thanks for the support guys!

 

[JRW]

Yep
There is no integer to real
It's double integer to real

 

[Jan Steen Nielsen]

Hello, I'm Jan Steen Nielsen
I know why you FB121 for Simatic S7-300/400 does not work.
If you change an input BOOL from e.g. default=FALSE to TRUE and then
delete your BOOL-bit hereafter so the input is now empty, then
the datablock will still remember the input as = TRUE.
This means, that all inputs to a datablock are retentive!.

I have improved my FB121 so now it makes an reset to default
if and only if the inputs are left behind as empty "pins".

You may get this updated version by mailing to me

Regards
Jan Steen Nielsen
[email protected]
Denmark