Diagram does not read channel names from .ddf file

[HansN]

I am developing a data collector with possible export of .ddf files for DASYlab import.

The file format shall be according to the DASYLab document "DASYLab File Formats"

Everything works just fine except for that the channel name and unit strings are not read and displayed in the chart.

Any hint someone?

[HansN]

More info:

I am working on a trial version of DASYLab 10.

In the tutorial there is an example "Read Data from Files" but the DEFWRITE.DDF file seems to be missing in the installation.

[MHa]

Hello HansN,

I'm unsure if I correct understand - you would like design your own DDF writer, based in any source code project from you? You would like implement the sources to write a DDF file into your C/C++ project?

Best regards,
MHa

[CJ_Butler__DASYLab_Pro]

I set up a Generator, and connected it to a Write Data module, and configured 5 channels, each with unique name and unit.

I then used the Options menu, Copy Channel Names, to copy the names to the Write Data module.

I ran for several seconds, to store data.

I then created a new worksheet with a Read Data module, configured to read the file that I had just created. I connected it to a Chart Recorder, configured to display the Y Units. 

I again used the Copy Channels names Option, and started the worksheet. The original channel names and units correctly display.

Channel names do NOT copy by default. You must manually copy them, or set the Options, Global Settings, to copy them each time the worksheet starts. This was a deliberate decision, to conform with behaviour in earlier versions of the software.

Units always follow the data, and can be transformed by the computation. They do copy automatically.

[HansN]

Hi, thanks for your answers!

Yes MHa, I have incorporated a .ddf writer unit in my program written in Borland Delphi pascal, along with writers for Diadem .dat and .I16, RPCIII .rsp and Excel .ddf files. They work nicely except for the flaw I want to get right.

CJ: Thanks a lot, I am not a regular user of DASYLab so I didn't know that one has to copy manually.

Now I created a worksheet with a Read Data module and a Y/t Chart module and read my file and the channel names were displayed ok but not the units. I have put the channel units and names in the Channel Headers as null-terminated strings.

Now when I'm testing a file generated from within DASYLab I see that the Channel name is fetched from the Channel header but the unit from the table in the Data Source string in the First Global Header! This is not documented in the Files and File Formats documentation I have. I would like to know how I have to format the Data Source string to make DL to find the unit string.

[HansN]

One more: in the DASYLab generated data file the channel units are not stored in the Channel Headers at all, there is just a zero byte immediately before the Channel Name string.

[HansN]

Hi again,

Where I am now: I have succeeded in making DASYLab fetch the unit string by copying the syntax in a DASYLab generated data file.

I had to pad the unit names with two blanks otherwise all letters were not displayed!

I would really prefer to get in touch with someone involved in the DASYLab development.......

[CJ_Butler__DASYLab_Pro]

Contact your local DASYLab reseller, and they can refer you to the correct resource.

[HansN]

I thought there were people with this knowledge on this forum.....

As it seems like I have found a workaround for my problem it's ok for me, I was only a little curious about this odd behaviour of DASYLab and why the documentation doesn't contain the correct information.

Thank you anyway!

Cheers.