MDF3: Conversion is lost after write

[johp1029]

Hi,

a co-worker of mine is using this library to open a MDF3 file, change some values and write it back to a file. He noticed, that textual conversions get lost after writing the file. Steps to reproduce:

• Open a MDF3 file
• Print a channel with textual conversions
• call 'write' method to save to new file
• Open new file
• Print same channel

The output looks like this:

OpenFile, Print Channel:
 {   'conversion': {   'parameters': {   0: {   'Textrange': '',
                                                'lowerRange': 0.0,
                                                'pointerToTXBlock': 0,
                                                'upperRange': 0.0},
                                         1: {   'Textrange': 'Vorwaerts',
                                                'lowerRange': 0.0,
                                                'pointerToTXBlock': 115816,
                                                'upperRange': 0.0},
                                         2: {   'Textrange': 'Rueckwaerts',
                                                'lowerRange': 1.0,
                                                'pointerToTXBlock': 115830,
                                                'upperRange': 1.0},
                                         3: {   'Textrange': 'Init',
                                                'lowerRange': 2.0,
                                                'pointerToTXBlock': 115846,
                                                'upperRange': 2.0},
                                         4: {   'Textrange': 'ungueltig_oder_nicht_verbaut',
                                                'lowerRange': 3.0,
                                                'pointerToTXBlock': 115855,
                                                'upperRange': 3.0}},
                       'type': 12},
     'data': array([0, ..., 3], dtype=uint8),
     'description': 'Drehrichtung Rad HL',
     'master': 't_27',
     'masterType': 1,
     'unit': ''}

 Save File

 Open New File, Print Channel:
 {   'conversion': {   'parameters': {   }, 'type': 65535},
     'data': array(['V', ..., 'u'], dtype='|S1'),
     'description': 'Drehrichtung Rad HL',
     'master': 't_27',
     'masterType': 1,
     'unit': ''}

Before writing, the channel contains a textual conversion and the data array contains numerical values.

After writing and reopening the file the conversion is lost and the data array contains only the first letter of the String representation.

Debugging showed that data is correct until this line is executed (in mdf3reader.py): fid.write(pack('<' + dataTypeList * nRecords, *records)) # dumps data vector from numpy

Regards, Johannes

[ratal]

It could be textual conversion function testRangeTableConv bug or in the write3 function. Coud you please do after open file ?: mdfreaderInstance.getChannelData(channelName) to have a look at the array and check if it is already ['V', ..., 'u']

[ratal]

I have found the bug in write3. The numberOfBits considered was not correct in case of string array. Give a try to latest commit

[johp1029]

Ok, the latest commit solves our problem. Thank you!