[W] Setting TD on serial port high using VISA

[Ferry Toth]

I have an evaluation board of an A/D converter that is powered by the TD
line from the serial (RS232) port. Communication with the board is done
using toggeling/reading the RTS/CTS/DTR lines. To power the circuit I need
to set TD high, but I can't find a way to control this pin using VISA,
except sending a break, which will only power the line 250ms - 500ms.

Any tricks?

Ferry Toth
Enraf BV, Delft, Nederland

[Helmut Hullen]

Hallo, Ferry,

Du meintest am 08.09.99 zum Thema [W] Setting TD on serial port high using VISA:

> I have an evaluation board of an A/D converter that is powered by
> the TD line from the serial (RS232) port. Communication with the
> board is done using toggeling/reading the RTS/CTS/DTR lines. To
> power the circuit I need to set TD high, but I can't find a way to
> control this pin using VISA,

Try "advanced/memory/out port".

Viele Gruesse!
Helmut

[Ferry Toth]

Helmut Hullen wrote in message
news:7OV-kdScfjB@hhullen.btx.dtag.de...
> Hallo, Ferry,
>
> Du meintest am 08.09.99 zum Thema [W] Setting TD on serial port high using
VISA:
>
> > I have an evaluation board of an A/D converter that is powered by
> > the TD line from the serial (RS232) port. Communication with the
> > board is done using toggeling/reading the RTS/CTS/DTR lines. To
> > power the circuit I need to set TD high, but I can't find a way to
> > control this pin using VISA,
>
> Try "advanced/memory/out port".

Will this work with WinNT? That's why I want to use VISA.

Ferry

[Helmut Hullen]

Hallo, Ferry,

Du meintest am 13.09.99 zum Thema Re: [W] Setting TD on serial port high using VISA:

> > Try "advanced/memory/out port".
>
> Will this work with WinNT? That's why I want to use VISA.

There are many ways accessing ports under NT. Maybe the newest LabView
version has implemented it - ask NI.

Another way:
"directnt.zip" from the "c't" filebox (www.heise.de/ct)
Some guy from Cambridge (?) UK has sent me "accesshw.zip", it is designed
especially for LabView (but its size is more than 1,6 MB).

Viele Gruesse!
Helmut

[Stefan Tauche]

Hi,

get the AccessHW driver from national instruments www-site.
it allows direct register access within winNT.

Regards
Stefan 😉
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