What do you mean by signal range


View Full Version: IEC870 double messages



2nd September 2011, 06:07
Hello

How can I meaningfully evaluate data points of the type double message (IEC type 31) in Zenon?

Thank you in advance

2nd September 2011, 8:27 am
What do you mean by "evaluate"?

The value changes are saved in the archive, and very important data points possibly also - in the CEL or AML. They are always saved there with the received timestamp.

The representation in the build:
- very simple - numeric - number element
- nice graphic - Combi-Element, your own or e.g. symbol Combi_SWITCH_01 / 02 from the global symbol library \ Substation

5th September 2011, 8:00 am
By evaluating, I mean. Whether bit 0 or 1 is set ...

5th September 2011, 8:47 am
And what do you want to do with this information?

Please specify your question or just take a look at the zenon help:

represent in a picture? -> picture elements
to save? -> Historian / CEL
to prevent the execution of certain actions depending on a variable value? -> Interlocks / the interlocking conditions in the command
trigger an alarm or function? -> reaction matrix / limit values.


The iec870 driver uses DPI / DCS mapping by default. A variable in zenon that corresponds to a colon can also have 4 states: 0 = OFF, 1 = ON, 2 = INTERMEDIATE, 3 = FAULT. It is a numerical variable and the 2-bit information is converted in the driver.

5th September 2011, 09:33
I already understand what you mean by the numerical evaluation ...
However, I don't really like the result. The table below comes out when I display the double message as a numerical value.
How can it be that the double message "01" results in the value zero in the evaluation ?? And otherwise the values ​​have no relation to the value in the variable?

Bit 1 | Bit 0 | value
0 | 0 | 15748
0 | 1 | 0
1 | 0 | 7874
1 | 1 | 23622

5th September 2011, 11:17 am
the double message "01" results in the value 0 due to DPI / DSC mapping.

As far as the rest of the values ​​are concerned, I suspected that in your project (for the variable) a different MIN / MAX value was set in value calculation - value adjustment linear - measuring range than in value calculation - value range control - signal range

5th September 2011, 12:44
the double message "01" results in the value 0 due to DPI / DSC mapping.

As far as the rest of the values ​​are concerned, I suspected that in your project (for the variable) a different MIN / MAX value was set in value calculation - value adjustment linear - measuring range than in value calculation - value range control - signal range

Hello yes beginner mistake. Shortly after my last post, I also found out that the calculation of values ​​did not fit.

But thanks for the help anyway ...

Kind regards

5th September 2011, 16:08
What I noticed, however, is that the bits that come from the controller do not match the bits that arrive in the Zenon

in the PLC
Bit 1 | Bit 0
1) 0 | 0
2) 0 | 1
3) 1 | 0
4) 1 | 1

in Zeno
Bit 1 | Bit 0
1) 1 | 0
2) 0 | 0
3) 0 | 1
4) 1 | 1

Is that normal or is there another attitude wrong? What's the deal with the DPI / DSC mapping?

6th September 2011, 07:17 am
Your tables don't show anything other than DPI / DSC mapping.
If you use the words of zenon help:

The driver converts the values ​​of double messages (DPI and DCS) for the runtime: intermediate | off | on | fault in: 2 | 0 | 1 | 3, so that in runtime e.g. the value 0 means OFF and 1 means ON.

in bits:
in the PLC
Bit 1 | Bit 0 __ value decimal _ meaning
1). 0 | 0 _______ 0 _________ INTERMEDIATE
2). 0 | 1 _______ 1 _________ OFF
3). 1 | 0 _______ 2 _________ ON
4). 1 | 1 _______ 3 _________ FAULT

in zenon
Bit 1 | Bit 0 __ value decimal _ meaning
1). 1 | 0 _______ 2 _________ INTERMEDIATE
2). 0 | 0 _______ 0 _________ OFF
3). 0 | 1 _______ 1 _________ A
4). 1 | 1 _______ 3 _________ FAULT

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