Detect communications failure in WinCC flex

[manmeetvirdi]

Coordination Area Pointer

Hi there
This is what help manual of the WinCC Flexible have to say about Coordination Area Pointer

"Operating mode

As soon as the HMI device is switched offline by the user, the operating mode bit is set to 1. In normal operation of the HMI device, the state of the operating mode bit is "0". You can find out the current operating mode of the HMI device by querying this bit."




This "operating mode" is the 1st bit of the defined word.

Assuming by offline its meant that PLC connection is broken then by reading this bit and opening a page when it set to 1 through a script shall be easy.At least in theory.

Will have to give try to this method !!

 

[lauwerstim]

This is not possible because this bit isn't updated anymore when WinCC looses connection. The bit just stays 1 when the connection dies (in the WinCC, in the plc iet does change, but since there's no comm,...

 

[manmeetvirdi]

Yea lauwerstim
At least in simulation its not working have to give try with HMI itself.

But the following method do work, but has some issues (speed issue) which needs to be ironed out.

STEP-1)
In PLC Write this:

AN M9.0
FP M9.1
S M9.0

STEP-2)

In HMI make a tag say always_on=M9.0

Then in script the following:

Dim a1
a1=SmartTags("always_on")
If a1=True Then
SmartTags("always_on")=False
Else
HmiRuntime.BaseScreenName= "alarm"
End If


STEP-3)
Call this script from Scheduler after every 1 minute

///////
Now if PLC is stoped or connection is broken the "alarm" screen
pops up.

Idea is PLC will always keep M9.0 TRUE, whereas HMI will reset it if this bit is TRUE. If communication fails and when this script is executed by HMI it will reset it, and then on second execution it will call the "alarm" page.

Now if I call this script from Scheduler(after every 1 min) this works, problem is it takes 2 minutes to deduct the connection failure.
Iam trying this in TP277, I think in MP277 there is an option of "simulate tag" through which speed can be improved.
K will come up if I finds anything better.