During serial port communication (writing/transmission) is it possible to explicitly set the states of the RTS and DTR signals? Do I have to use a C++ routine?

[mertaugh]

I'm trying to interface LabVIEW with hardware connected to the serial port that requires the states of RTS and DTR signals to be set during communication as follows:

Signal RTS DTR
Reset 0 0
Logical '1' 1 0
Logical '0' 0 1
Standby 1 1

During data transmission the recommended signal stream format is as follows (the wait ensures that one of signals is always "on"):

Standby | '1' | Wait | '0' | Wait | '1 ' | Wait...
_____________________ _____________________
RTS _
| |_____|
________ ___________________ ________
DTR _| |_____| |_____|

The recommended time for the '1', '0' and 'Wait' states is at least 0.5ms.

Exactly how could this signal be generated in LabVIEW. If I simply used the Serial Port Write.vi would it meet this specification? Would it be simpler to write the routine in C to do this?

Thanks for all your help.

-Don

[RobertoBozzolo]

I never used it, so I don't know what is the performance of it, but there is a VISA property node with which you can set or reset the individual lines of the serial port.
Go to the Functions>>Instrument I/O>>VISA>>VISA Advanced palette and drop a Property node on you diagram, then wire it to a VISA open set for example to ASRL::1INSTR for COM1, then right click on the property node and choose Properties >> Modem line settings: inside it there are items for DTR and RTS lines.
Hope it helps.
Roberto

[shoneill]

Hi Don,

I f you use VISA for the communication, you can access the individual lines
on the serial port using a property node.

Shane

mertaugh schrieb in Nachricht
<506500000008000000FF1E0000-986697009000@quiq.com>...
>During serial port communication (writing/transmission) is it possible
>to explicitly set the states of the RTS and DTR signals? Do I have to
>use a C++ routine?
>
>I'm trying to interface LabVIEW with hardware connected to the serial
>port that requires the states of RTS and DTR signals to be set during
>communication as follows:
>
>Signal RTS DTR
> Reset 0 0
> Logical '1' 1 0
> Logical '0' 0 1
> Standby 1 1
>
>During data transmission the recommended signal stream format is as
>follows (the wait ensures
that one of signals is always "on"):
>
> Standby | '1' | Wait | '0' | Wait
> | '1 ' | Wait...
> _____________________ _____________________
>RTS _| |_____|
> ________ ___________________
> ________
>DTR _| |_____|
>|_____|
>
>The recommended time for the '1', '0' and 'Wait' states is at least
>0.5ms.
>
>Exactly how could this signal be generated in LabVIEW. If I simply
>used the Serial Port Write.vi would it meet this specification? Would
>it be simpler to write the routine in C to do this?
>
>Thanks for all your help.
>
>-Don