WinCC Flexible Quirks

tvey

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Join Date
Mar 2005
Location
Halifax, NS
Posts
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Hi folks,

I worked on a project recently using Siemens WinCC Flexible and encountered a somewhat annoying issue with alarming and alarm 'trigger bits'.

WinCC Flexible was, apparently, at one time called 'ProTool'. The ProTool package used a different byte organization (look up 'little endian vs. big endian').

I'm using S7-200 series addresses below.

In one scheme, a word looks like this:
Byte2 Byte1
VB907 VB906


In the other scheme, a word looks like this:
Byte1 Byte2
VB906 VB907


The S7-200 series PLC uses the first scheme. WinCC Flexible ALSO uses the first scheme, EXCEPT when it comes to looking up text for alarm trigger bits.

Let's say I have an alarm assigned in the PLC to bit V906.0 - "Y-Axis Failed to Home'.

To configure an alarm in WinCC Flexible, you must create a tag to serve as the 'trigger tag', then assign alarm text for each 'trigger bit' within the trigger tag.

Logically, I expected to assign the trigger tag to VW906, and then assign the appropriate alarm text to 'trigger bit' 0.

HOWEVER, because of the (undocumented, as far as I can tell) endian issue above, this setup won't work! WinCC Flexible is apparently smart enough to know that bit V906.0 is set, but falls down when it does the lookup for the alarm text.

To make the alarm text show up properly, you must account for the swapped byte order - so instead of assigning the alarm text to trigger bit 0 (as would match the actual alarm bit in the PLC), you must assign the alarm text to trigger bit 8 (and so on for the low byte).

Siemens tech support enlightened me to this issue yesterday. I walked our client through the 'fix' but haven't yet heard back whether or not the problem is actually solved.

Has anyone else encountered an issue like this (or similar) with WinCC Flexible or other HMI package?

-Trevor


Here is an example of 'trigger tag' and 'trigger bit' assignments:

'trigger tag' assignment
alarm_tags-cropped.png


'trigger bit' assignment
alarm_mapping-cropped.png
 
I have this problem all the time

I don't have a good answer for you but I do know what you are talking about. I don't think its just the alarms. Unless you config the tag just for a single bit then you will have this problem. I see this a lot when doing bits under animation. I have some words that change colors on the screen depending on the bit. I find myself looking for a bit that I know works and then counting up/down from it to set the one I am adding. Its a lot of trouble for something that should be so simple.

Maybe some of the good Siemens people here can give us a good reason.
 
This was the same problem in Protool. But Protool had the important advantage that you could directly see the address of each alarm in the alarm editor.

Maybe you can get an easy direct link between the addresses in WinCC Flexible and the adresses in S7, by setting up a BOOL array in STEP7. I think that the bit addresses is Flexible will be the same as the array adresses in S7. Havent got the time to try it out though.
 
Trev,

as Jesper indicated Protool did the same except when you defined your alarm window areas it displayed at the bottom what bit the message fell on.

Now with Flex you have greater...flexibilty but with it the ability to tie yourself in knots.

If you want your messages to line up with your low order bits the manipulate your bit number and it will line up.
Message 1 = Bit8
Message 2 = Bit9
Message 3 = Bit10...


Message 9 = Bit1
Message 10 = Bit2

Or simply remember to make AlarmWords fall on even Address(good practice) and start with ODD and work to even.

I don't bother with any of the above. I pass my AlarmWord into my alarm block and pass in the bit I want to set. I then write 16#0001 in to accum and rotate left the bit number of places I passed in. Then simply OR with AlarmWord (if Alarm present) and pass back out of block IN/OUT. The whole thing takes care of it's self. Self documented and easy to follow.

Nick

I udestand this is for Step7 not MicroWin...but you could do the same.
AlarmTag1.JPG
 
Nick B said:
Message 1 = Bit8
Message 2 = Bit9
Message 3 = Bit10...


Message 9 = Bit1
Message 10 = Bit2

Just to correct you:

Message 1 = Bit8
Message 2 = Bit9
Message 3 = Bit10...

Message 9 = Bit0 (As bitcounting starts at 0, not 1)
Message 10 = Bit1

Greetz
Jeebs
 

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