siemens Scale with Parameters?

[L D[AR2P#0.0]]

Why did you use a function block as opposed to a function?

 

[eoates]

Reply to LD[AR2,P#0.0];

I am a lot more familiar with Allen Bradley PLC's & PAC's, so when one customer specified a Siemens S7-300, and since one thing we needed was the equivalent of an SCP instruction, and having been using RSLogix5000 with an SCP Add-On Instruction, I searched for information on how to do the equivalent with Step7.

I found a series of videos on YouTube by TheReimber". From these videos, my understanding is that everything can be done in either FC's or FB's, but FB's allow easier connection with Data Blocks etc., and are better suited for functions that are used over & over in many places throughout the program whereas FC's are better suited to used as calls from the Main Routine (OB1), like subroutines in Allen Bradley.
That said, however, this may be a matter of personal preference.

Anyway, FYI, here is a link to the specific video regarding Functions & Function Blocks from "TheReimber":

http://www.youtube.com/watch?v=4HgyBjH-rxY

This fellow has produced a series of very informative videos for both Step 7 (about 30 of them) and also for WinCC (about 25 of them), although the sound is very faint on some of the Step 7 videos, but this is not much of a problem if you have a good set of speakers connected to your computer so you can turn up the volume sufficiently.

 

[eoates]

Further Reply to LD[AR2,P#0.0]

I have since revised the Siemens equivalent of the Allen Bradley SCP instruction.
After some basic instruction by our local distributor, I learned that the advantage of the FB over the FC in a case like this is that the FB's have a feature that the FC's do not have.
This is the ability to hide internal words, bits etc. of the function that are not needed by the calling function or OB by designating them as "static".

Please see the attached printout ("FB1_SCP_r01.pdf")of the revised version where the words “Temp1” through “Temp4”, "Offset" and "Rate" have been moved into the "Static" folder.

Without this feature, the words “Temp1” through “Temp4”, "Offset" and "Rate" unnecessarily appear in the calling function which clutters things pretty badly.

Now, with this revision, when the SCP Function Block is called, only the needed parameters appear, as seen in the attached printout of FC40 which is calling the SCP Function Block, FB1.

(Please see the attachment "FC40.pdf")

 

[PeterW]

He asked the question regarding FC/FB because you used no STAT's, in this case it would be better to use a FC as an FB would use a DB without any benefit.