pl2303 usb uart OWX ds18b20

[kroonen]

Hi,

I read this on a page so I thought it should work with fhem too

http://haklabos.wordpress.com/projekti/digitemp/

I only used a pl2303 usb to uart.

With digitemp it words fine

digitemp_DS9097 -i -s /dev/ttyUSB0
DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU General Public License v2.0 - http://www.digitemp.com
Turning off all DS2409 Couplers
.
Searching the 1-Wire LAN
28A1677D0400009E : DS18B20 Temperature Sensor
ROM #0 : 28A1677D0400009E
Wrote .digitemprc

digitemp_DS9097 -a
DigiTemp v3.5.0 Copyright 1996-2007 by Brian C. Lane
GNU General Public License v2.0 - http://www.digitemp.com
Mar 15 13:55:42 Sensor 0 C: 19.25 F: 66.65

But get an error with OWX first:

2013.03.15 13:57:24 3: Opening OWio1 device /dev/ttyUSB0
2013.03.15 13:57:24 3: Setting OWio1 baudrate to 9600
2013.03.15 13:57:24 3: OWio1 device opened
2013.03.15 13:57:24 1: OWX: Serial device /dev/ttyUSB0 defined
2013.03.15 13:57:25 1: OWX: 1-Wire bus OWio1: interface not found, answer was 0x17 0x41 0xab 0x20 0xfc


any idea what goes wrong?

[Prof. Dr. Peter Henning]

No idea from the few information bits you gave.

If the kernel module for PL2303 is properly installed, OWX also works fine with PL2303 converters.

Please post:
- Type of FHEM system (Desktop Computer ? Fritzbox ?)
- Type of 1-Wire Interface attached to the PL2303 converter ?

rgds

pah

[kroonen]

Well

I'm using it on a desktop fhem.

I attached the pl2303 directly the ds18b20.

the data pin from the ds18b20 is attached to both rx and tx.

the other is directly connected to the gnd and +5v to the pl2303

in digitemp is it an ds9097 and works.

[Prof. Dr. Peter Henning]

No, this does not work.

OWX does not emulate the 1-Wire Bus communication - rather it needs a serial-to-1-Wire Adapter attached to the PL2303.

See here: http://www.fhemwiki.de/wiki/Interfaces_f%C3%BCr_1-Wire

rgds

pah

[kroonen]

It should than work if I put an after the pl2303 uart the ds2480b and 2 condenators, as on the ft232rl?

http://www.fhemwiki.de/w/images/f/f6/USB_Interface.png

i'm using like this one

regards Richard

[Prof. Dr. Peter Henning]

Careful, is it the RS232 output or the UART output ? They are inverted, and if you have the "other" one Pin 6 of the DS2480 needs to be grounded instead of set to VDD. Extract from the DS2480 data sheet:


RXD/TXD Polarity Select. RXD/TXD polarity select; tied to GND for RS232
(12V or 5V) connection; tied to VDD for direct connection to UART chip.

rgds

pah

[kroonen]

it's uart output. So that same as your scheme?

[kroonen]

And another queation, is an passive interface possible on an uart, instead of rs232?

[Prof. Dr. Peter Henning]

I have used the UART scheme, correct.

I would opt for a passive interface only as a last resort - main objection is, that there is no true ground and that there is no active signal formation.

OWX in principle supports also the passive interfaces, but I have not tested this for some time.
Well done cheap active interfaces may be found here:

http://www.shop.kristech.pl/c/31/1-wire-konwertery.html

rgds

pah