Use VISA when connected directly via RS232?

[cramezl]

I'm not using a DAQ to connect to a pressure transducer I'm trying to read from. Do I need to use VISA to connect the gage to LabVIEW?

[crossrulz]

VISA is the preferable way to use the COM port in LabVIEW.

[withravii]

can anybody please help in controlling the direction of dc motor through  switches in front panel..i.e if i press switch1, motor moves in CW direction and if i press another switch, it rotates in acw direction..

[Izzzzz]

Hello withravii,

What type of motor are you using (stepper, servo, brand, type, and manufacturer)? Do you have a drive for that motor? How is the motor connected to your computer? What sort of Motion Controller (i.e Motion Controller PCI/PXI card) do you have for that motor? Is it a National Instrument Motion Controller?  Did the motor come with drivers?  Have you taken a look at this page to see if there are drivers available for your motor? I apologize for all the questions but they are necessary in order to get a full picture of your application so that I or anyone can give you an appropriate answer. 

Regards,

Izzy O.

Applications Engineer

National Instruments 

[withravii]

Hello Izzy O,

thanks for the reply.Actually I am using dc geared motor and it would be connected to the pic microcontroller circuit and to the laptop through USB to serial converter, motor driving IC which I will use is L293D. My objective is just to control the direction of the dc motor through labview.

[Dennis_Knutson]

So what exactly do you need help with? If this pic and board is something you designed, you are the only one who knows what data to send. I would suggest you do some basic debugging with a terminal emulator program such as hyperterminal, procomm, putty, etc. before you write the LabVIEW code. After you get that working, your program should be fairly easy to write.

[withravii]

actually I am new to LabVIEW, and I have no idea how to program in labview using visa write to control the dc motor through switches in front panel

[Dennis_Knutson]

There are online tutorials to help you get started with LabVIEW. There are also a couple of serial examples that come with it. Basically, you use a VISA Write to send the necessary command. A Boolean for each direction, wired to a case statement with the VISA Write inside would be a simple starting point. As long as the button is true, the command would be sent.

[withravii]

It would be a great help for me if you can help with with a block digram connections.

[Izzzzz]

Hello Withravii,

Shown below is a quick example of what Dennis_Knutson is referring to, which is good idea for your application.

Regards,

Izzy O.

Applications Engineer

National Instruments 

[withravii]

Thanks Izzy O for your concern.

Regards

Ravi