Error on transferring from scanner to Python code

[MelStoltz]

I am trying this code out below.

import twain
sm = twain.SourceManager(0)
ss = sm.OpenSource()
ss.RequestAcquire(0,0)
rv = ss.XferImageNatively()
if rv:
(handle, count) = rv
twain.DIBToBMFile(handle, 'image.bmp')

It works fine until the rv = ss.XferImageNatively() part
then I get this error

Traceback (most recent call last):
File "C:\Paradigm1\test.py", line 5, in
rv = ss.XferImageNatively()
File "C:\Paradigm1\twain.py", line 2144, in XferImageNatively
return self.xfer_image_natively()
File "C:\Paradigm1\twain.py", line 1974, in xfer_image_natively
rv, handle = self._get_native_image()
File "C:\Paradigm1\twain.py", line 1901, in _get_native_image
(TWRC_XFERDONE, TWRC_CANCEL))
File "C:\Paradigm1\twain.py", line 1565, in _call
return self._sm._call(self._id, dg, dat, msg, buf, expected_returns)
File "C:\Paradigm1\twain.py", line 2320, in _call
raise exc
excTWCC_SEQERROR

Am I doing something wrong?

[denisenkom]

Try using higher-level function instead: http://pytwain.readthedocs.io/en/latest/twain.html#twain.Source.acquire_file

It should take care of this error. The error means you called function during wrong state.