RS-232 - USB or PCMCIA??

[Ed]

I want to add an RS-232 interface to my laptop for use in controlling an instrument from LabView. Nothing too demanding - need Baud rate of say 1200, and no handshaking required. I have spare USB and PCMCIA slots. Is there any preference for choosing an National Instrument's RS-232 to USB or RS-232 to PCMCIA interface??

I see the RS-232 to PCMCIA option is slightly cheaper.

Thanks.

Ed

[Chris_Rake]

Either interface should work just fine - however note that the USB-232 is supported under 2k and XP only, so if you have NT or 9x/Me, then PCMCIA is your only option.

[cyanopugnax]

What you can do if you want to use the usb port under Windows 9x/Me for serial devices is to connect the serial instrument with a usb-RS 232 adapter(Quite cheap.)Note you have to install the driver of the adapter first. Then you can use your VIs for serial communication (if you are using a VISA-VI for serial communication, LabView automatically adds a serial port). This way I have connected my serial instruments with LabVIEW. I think it will work also with W2K and XP.

Regards
Holger

[Charcinders]

I am using a usb - dual serial adaptor type USB-2COM made by a company called VScom to control equipment from LabView, running under Win Me. It works fine, and it's cheap!

Chris

[Henrik_Volkers]

We use cheap single USB->RS232 adaptors with Laptops and W2k running LV and VISA for low speed (1/s) instruments readings. With a small 4x hub we run it successfully with up to 5 instruments (including the internal COM1)

Some comments:
Different adaptors behave different in how they show up for the system (depending on their driver).
I have seen two types of portbindings:
1- COMXX depends on USB port position including hub position
2- COMXX depends on the adaptor (eg. some internal number and the sequence when you first connect it to the PC)

So for your application make shure you can select your COMport (also in ASRL notation)

Greetings from Germany

Henrik