[sane-devel] Epson 1260 driven out-of-range by sane-plustek?

[Karl Heinz Kremer]

On Sunday, August 24, 2003, at 06:39 AM, Jaeger, Gerhard wrote:

> On Samstag, 23. August 2003 14:27, Michael Nottebrock wrote:
>> The scanner works fine, except that doing a complete preview seems to
>> slightly drive the movable parts of the scanner beyond their limits - 
>> there
>> are (a few, sometimes none) unhealthy sounding noises towards the 
>> very end
>> of the preview scan. Is there a way to correct this via driver 
>> options? I
>> noticed the posOff and negOff options, but I'm not entirely sure I
>> understand what they do.
>>
>> This is sane-backends 1.0.12 on FreeBSD 4.8-STABLE.
>
> Hi,
>
> there are no options which correct this behaviour! I got a similar 
> report on
> that for a Plustek device too, but I'm not able to reproduce this 
> here...
> You might tweak the settings in the source-code (file plustek-devs.c), 
> and
> reduce the length of the scan-area - currently 3508steps (29,7mm for 
> A4 /2,54
> * 300 = 3507,87 --> rounded up to 3508)...
>

I'm definitely no expert on the Plustek backend, or the devices it 
supports, but I
have an opinion anyway ;-)

 From Michael's initial email, it sounds like this is not happening 
every time. This
could be in indication that the problem is not the length of the scan 
area, but maybe
a problem with the origin: If the scanner does not start at 0, then the 
3508 steps maybe
too many. When you bring the scanhead back to the zero position, is it 
possible that
the scanner needs a little longer than you (or the software) expects it 
to take, and therefore
the start scan command comes too early?

Karl Heinz