On Fri, 4 Jun 2010, Harold wrote:
> What do you mean by "single device is connected full duplex"? That does
> not make sense. Full duplex means that it can transmit and receive at the
> same time, which means it has separate transmit and receive connections.
> RS-485 uses the same differential pair for both transmit and receive, in
> half duplex, doing one at a time. It is not possible to connect an RS-485
> device to an RS-485 port full duplex.
The TS7260 option provides a diff pair for TX and a diff pair for RX on
/dev/ttyAM1 (COM2). I have a device which has similar - the TX pair of one
is connected to the RX pair of the other.
You are probably saying that this is not proper rs485. Fine, sorry for
using the wrong terminology.
So rephrasing, is anybody using the rs485 option on the TS7260 in this
mode?
Can they verify that programmatically one can just treat it as a normal
full duplex serial connection?
>
> Usually you can set up an RS-485 port so that it defaults to receive
> mode, and automatically switches to transmit mode only while it is
> transmitting, then switches back to receive mode when it is done
> transmitting. But I have never used an RS-485 port on a TS-7260, so I
> cannot say how it works there.
>
> Most often, RS-485 communication problems are due to incorrect wiring, since
> everyone seems to use different pinouts.
>
> --- In Jim Jackson <> wrote:
>>
>>
>>
>> I'm trying to speak to a single RS485 device connected to the second port
>> of a TS7260 with the RS485 option.
>>
>> I've never dealt with rs485 before. Am I right in thinking that, if a
>> single device is connected full duplex, then I should just treat,
>> programming-wise, the interface as if it was an rs232 port?
>> 'cos I've done that and am getting nothing. I'm getting the guys that did
>> the hardware to double check their wiring to the COM2 header.
>>
>> If any RS485 expert could give any hints/advice it would be much
>> appreciated.
>>
>> Jim
>> p.s. the rs232 code works fine on /dev/ttyTS0 (com3) and on the serial port
>> of my development machine.
>>
>
>
>
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|