S7- Date Extraction not working

[PLC_talk]

Hello All,
I am facing a wierd problem on S7-400 PLC.
I am trying to extract date using following simple logic & using PLCSIM to test it.
SFC1 reads the Date & time to a #cdt1 temp DT type. This temp #CDT is sent as input to FC^ DT_DATE function & the ouput I receive is 0 (DEC) or 1990-1-1, I checked up the clock setting & it is showing properly the PC current date & time.
The FC8 function works fine & shows the current time.
Is this PLCSIM problem or am I making mistake somewhere?

Any suggestions????
Thanks,

 

[dchartier]

Hello PLC_Talk;
Here is an extract from the following Siemens' support named :
"Difference between PLCSIM V5.0 and a "real" automation system"

http://support.automation.siemens.com/WW/llisapi.dll?csquery0=sfc1&aktprim=0&extranet=standard&func=cslib.csinfo&lang=en&nodeid0=10805405&objaction=csbrowse&objid=10805405&siteid=cseus&subtype=133000



Please note that the following SFBs and SFCs are NOPs (no-operations):

• SFB12, SFB13, SFB14, SFB15, SFB16, SFB19, SFB20, SFB21, SFB22 and SFB23,
• SFC7, SFC11, SFC25, SFC35, SFC36, SFC37, SFC38, SFC48, SFC60, SFC61, SFC62, SFC65, SFC66, SFC67, SFC68, SFC69 and SFC81
• OB81, OB84, OB87 and OB90

So, SFC1 will not produce the processor time (it was never designed to read the PC clock anyway...).

Hope this helps,
Daniel Chartier

 

[L D[AR2P#0.0]]

SFC1 is not in the list of nops and does work in plcsim (V5.2) with a 317 as the CPU. What exactly is this "FC^ DT_DATE" ?

 

[dchartier]

Sorry about that, guys.

I stand corrected.
Daniel Chartier

 

[krk]

What exactly is this "FC^ DT_DATE" ?

He might have been holding the SHIFT key in.....

 

[L D[AR2P#0.0]]

Here's a link for an example of how to extract the date information:-

http://www.plctalk.net/qanda/showpost.php?p=191480&postcount=3

 

[PLC_talk]

Hello Guys,
Thanks for the information.
The weird thing is the same programmed worked next day! May be it just needed a PC reboot.
a. BTW FC^ is a typo, it's FC6

Thanks,