"Error 10: Read COM Failed" on Centos 6 / Prolific USB-serial converter

[wa4fom]

I've been trying to get some DS1820 sensors to work on a recently built CentOS box.
I'm using a Prolific USB-to-serial converter cable and a breadboarded sensor.  I'm
getting:

[root@zamilovana nagios]# digitemp-3.6.0/digitemp_DS9097U -v -i -s /dev/ttyUSB0

DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU Public License v2.0 - http://www.digitemp.com
Error 5: DS2480B Adapter Not Detected
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed
Error 10: Read COM Failed

Digitemp version is 3.6 (even though it says 3.5).  I tried the fix at:

       http://tech.akom.net/archives/60-Fixing-digitemp-with-LinkUSB-on-kernels-after-2.6.32-24.html

No joy.  Tried different USB adaptors (same chipset).  No joy (i.e., same symptoms).  I'm using
a very old (and hopefully reliable) circuit shown below:



The "lsusb" utility sees the adaptor.

    Bus 004 Device 052: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

The device file is there, and definitely can be written to by anybody.  I use root so I can
swat the fly with a sledgehammer.

       [root@zamilovana nagios]# ls -l /dev/ttyUSB0
       crwxrwxrwx 1 root dialout 188, 0 Dec  5 09:09 /dev/ttyUSB0

Linux version:  Centos 6, or specifically:

    Linux zamilovana 2.6.32-573.el6.x86_64 #1 SMP Thu Jul 23 15:44:03 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

I even rebuilt a second breadboard with fresh components.  No change.  Tried a second
Prolific adaptor cable.  No change.

I tied LEDs from the RXD and TXD data lines to pin 5 to observe the state changes.
I can "see" digitemp talking to the sensor, and it appears to answer.

I'm pulling my hair out over this one.  I have a lot of hair to spare, but I'd rather hold on
to it, so any suggestions would be welcome at this point.

Thanks!

[Brian C. Lane]

On Sat, Dec 05, 2015 at 06:24:03AM -0800, wa4fom wrote:
>
> I've been trying to get some DS1820 sensors to work on a recently built
> CentOS box.
> I'm using a Prolific USB-to-serial converter cable and a breadboarded
> sensor. I'm
> getting:

The PL2303 is, IMHO, a complete pile of junk. I've had worse luck with
them than I have with the DS2490 USB adapter. I use FTDI based adapters
with mine.

> Digitemp version is 3.6 (even though it says 3.5). I tried the fix at:
>
>
> http://tech.akom.net/archives/60-Fixing-digitemp-with-LinkUSB-on-kernels-after-2.6.32-24.html

Interesting, I don't remember seeing this reported before, and I
certainly don't have it in any of my working systems (all using kernel 3
or 4).

--
http://www.brianlane.com

[wa4fom]

Brian:

Thanks for the quick reply.  I managed to get an FTDI adaptor and am getting this now:

[root@zamilovana nagios]# /usr/bin/digitemp_DS9097U -s /dev/ttyUSB0  -i

DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU Public License v2.0 - http://www.digitemp.com
Error 5: DS2480B Adapter Not Detected

Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response
Error 7: DS2480B: Bad Response

At least it's a change.  The system sees the USB adaptor just fine, and my
little LEDs indicate it's talking to the sensor.  I tried even building a new
sensor breadboard (#3 now).  Same response.  Tried both DS1820 sensors and
DS18S20.  No difference.

I think it's Ouija Board time.  Any ideas?
Thanks in advance.

[Brian C. Lane]

On Sun, Dec 06, 2015 at 07:32:49AM -0800, wa4fom wrote:
>
> Brian:
>
> Thanks for the quick reply. I managed to get an FTDI adaptor and am
> getting this now:
>
> [root@zamilovana nagios]# /usr/bin/digitemp_DS9097U -s /dev/ttyUSB0 -i
> DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
> GNU Public License v2.0 - http://www.digitemp.com
> Error 5: DS2480B Adapter Not Detected
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
> Error 7: DS2480B: Bad Response
>
> At least it's a change. The system sees the USB adaptor just fine, and my
> little LEDs indicate it's talking to the sensor. I tried even building a
> new
> sensor breadboard (#3 now). Same response. Tried both DS1820 sensors and
> DS18S20. No difference.

Hmmm, by 'breadboard' do you mean you built your own adapter? If so then
odds are you need to use digitemp_DS9097 instead of 9097U which is the
one for the DS2480B chipset adapter.

--
http://www.brianlane.com