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Re: [Playerstage-users] Trouble connecting SICK to RS-422 through pci card (now with smaller attachment)
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From: Brian G. <br...@ge...> - 2005-08-12 18:19:44
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I think the Sealevel 422 card will also require changes in the driver
to the custom_divisor logic, as Joseph suggested. I recently tried
to get a PCMCIA 422 card (don't remember the vendor, but it was not
using an FTDI chipset) to work, without success. I don't completely
understand the custom_divisor stuff, which is complicated by the fact
that the "right" way to do custom speeds on a serial port changed at
some point in Linux (during 2.4, I believe).
Any volunteers to rework the speed logic to be more portable (e.g.,
specify a custom divisor or whatever is necessary in the .cfg file)?
At the same time, I think Cameron's idea of merging the three drivers
is a great one...
brian.
On Aug 2, 2005, at 12:56 AM, Cameron Stone wrote:
> I've recently had some experience with this beast. I was using a
> ftdi-based
> usb to 422 converter, but the trick to getting it working was on
> the lms
> side. We couldn't get it to respond to any packets, until we
> reversed the Tx+
> and Tx- connections on the lms291 end of the cable. After we did
> that it
> worked fine. This means either the documentation for the converter
> was wrong
> or the sick documentation was wrong. Apparently there is no pin
> specifications in RS422, so 422==custom cabling.
>
> Also, the lms291 talks a slightly different dialect to the lms200
> so the
> standard driver does not work. It causes some mangling of the data.
> I've
> written a shared object driver that seems to work. The driver is not
> complete, but works at 500kbps for range data. It either fails to
> ask for
> intensities correctly, or doesn't parse the returned packets
> properly, but
> the bottom line is that it doesn't give any non-zero intensities,
> despite the
> specs claiming it'll give 16-bit values.
>
> Good luck.
>
> Cameron.
>
> PS It wouldn't take much to incorporate this driver (and the pls
> one) into the
> main lms driver (lms200). The appropriate modifications could be
> selected on
> the fly by asking the laser itself what model it is.
>
> On Wed, 27 Jul 2005 10:32, joseph bebel wrote:
>
>> Hi,
>>
>> I have a SICK LMS 291 laser rangefinder(the 90 degree field, fast
>> scan
>> model) currently communicating with player over a RS-232 serial
>> line. I
>> would like to receive the readings at 75Hz, so we are using a 4 port
>> Sealevel systems RS-232/422/485 PCI card (model 7404) configured
>> (with
>> hardware jumper) to 422 mode. The crystal inside the card was
>> replaced at
>> the factory with a crystal that will allow exactly 500kbaud that
>> the sick
>> desires. We have a standard 10 foot RS-232 extension cable (M-to-
>> F, all 9
>> pins connected the same on each end; pin 1 to pin 1, 2 to 2, 3 to
>> 3, etc)
>> and a special RS-422 cable which crosses over the proper serial
>> lines(Rx-
>> on card to Tx- on LMS, Rx+ to Tx+, so on) and provides the jumper
>> on the
>> correct pins to set the SICK into 422 mode.
>>
>> However, when player attempts to communicate over the 422 serial
>> line, it
>> attempts to connect first at 38.4k, fails, drops down to 9.6k and
>> fails
>> again (regardless of the rate specifier in the config file)
>> Apparently I
>> need to change some options in the player code, such as setting
>> the custom
>> divisor for this particular serial card, and changing it so it
>> attempts to
>> change to 115.2k (instead of the 38.4k currently set) which is
>> what will
>> set the driver into 500k mode, after opening communication at 38.4k.
>> Unfortunately, the connection fails before that point is reached
>> so that is
>> likely not the problem.
>>
>> I have already contacted Sealevel support and they were unable to
>> assist me
>> beyond getting the card recognized by Linux and telling me that
>> the card
>> will recognize 115.2k as 500k instead of 38.4k(as with the USB-rs422
>> converters), so if anyone else has an idea how to open
>> communications over
>> 422 on this PCI card, I would appreciate it.
>>
>> Thanks
>>
>>
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>>
>
> --
> ===================================================================
>
> While working his way along a wall he came to a huge door, which
> artistically portrayed a group of prisoners apparently being
> given a complete medical check-up.
> -- Rincewind visits the Tezumen tribe
> (Terry Pratchett, Eric)
>
> Cameron Stone <cam...@cs...>
> ===================================================================
>
> <sicklms291.cc.bz2>
>
--
Brian Gerkey
br...@ge...
http://gerkey.org
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