DataPlugin for MDF4 Bit Count

[cg65]

Hi everybody,

I already can create a new MDF4 file and write data into the file.

The signals are stored as 64bit double values. I want to store my signals as 32bit floats so save space.

I found the documentation of Asam MDF4 DataPlugin https://www.ni.com/pdf/manuals/378544a.html

with the parameter nativedatatype. But i can't figure out how I can change the bit count of a signal to 32 bit.

Any help would be appreciated.

Thank you very much.

[Deus_ex_Machina]

What software are you using?

[Ideal_zzz]

I have also encountered this problem. Have you solved it?

[Barrows155]

---

@cg65 wrote:

Hi everybody,

I already can create a new MDF4 file and write data into the file. garageband

The signals are stored as 64bit double values. I want to store my signals as 32bit floats so save space.

I found the documentation of Asam MDF4 DataPlugin https://www.ni.com/pdf/manuals/378544a.html

with the parameter nativedatatype. But i can't figure out how I can change the bit count of a signal to 32 bit.

Any help would be appreciated.

Thank you very much.

---

Fast Python reader and editor for ASAM MDF / MF4 (Measurement Data Format) files warning: manifest_maker: MANIFEST.in, line 13: path 'docs/' cannot end with Hello @Luislopezcmi, Matlab can read hdf5 files directly, so export hdf5 file If you think this could be a good addition, I'm happy to help review further what.

[cg65]

Actually I did. You can set the attribute "channel_data_type".

The meaning of the different number (in my example 5 or 6) are explained in the readme of the MDF4 Pluging.

[Ideal_zzz]

Thank you for your reply，I know the meaning of the different number.

Sorry, I don't see how to write MDF file on your attached drawing.I write MDF-ZIP data via Express VI to reduce the file size effectively, but some values on Canape cannot be shown correctly as strings (see attached picture),  how do you solve this problem?

[Ideal_zzz]

Sorry, The abnormal display photo was sent wrong.

[cg65]

I am not shure if your problem is directly related to mine. I just wanted to store numeric  values in the mf4 file.

It looks like the value table is missing in your abnormal display file. 

The value table matches the numeric value (which is stored in the mdf file) to a "nice" displayed string etc.

I attached two pictures whichs show how i create a MDF file and a channel group. In the second you can see how I write data into a channel group. The sub vi "Array to Wace Form" is basically the image from my first answer.

Unfortunatelly, I never tried to add a value table to an MDF file using LabView, but I suggest to use Vector's MDF Validator to check if there is a value table in one file and missing in the file which was created by LabView.

[Ideal_zzz]

It is the first time for me to hear about the concept of value table. Thank you very much for your advice and I will continue to explore it.