• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Which interface to use - USB, GPIB, or RS232 while both supplying and reading a DC Voltage?

Not open for further replies.


New Member
Hey all,

For a project I want to supply a DC voltage with the following device:

Simultaneously, I would want to measure the voltage using a DMM:
Either with:
of which the latter one has option for a GPIB interface.

I want to control/measure and log via one PC. As I am totally new to Labview / SCPI commands or whatever is needed to steer and read these devices, I have the following questions:
- Does anyone have recommendations which interface to use (USB/GPIB/RS232)?
- What are the advantages/disadvantages to each of them?
- Which interface is the best to use for beginners (I never even heard of GPIB and RS232 before!)?

Thank you all! :)


Well-Known Member
Most Helpful Member
You never heard of RS-232? I'm sure you've seen it. Maybe you just did not know what it was called.

Unless your PC has RS-232 or GPIB connectors on it, you're stuck with USB. You seem to have access to Labview so just use that and the drivers that BK provides.

If you need to write your own software on the PC, for whatever reason, then RS-232 is probably easier to code for than USB. The underlying electrical/software protocol is UART (it is used with RS-232, , RS-422, RS-485 which define how things are physically). You install the FTDI drivers into the PC and it makes the RS-232 port appear as a virtual COM port so it appears as an RS-232 port even though it's a USB port in reality. You can access the port via software on the PC (i.e. HyperTerminal, RealTerminal, or some other Terminal software, or whatever software you write on the PC).

EDIT: I checked the manual and software for both meters and the USB port is actually exactly but even more convenient. They basically split off the RS-232 port inside the meter and connected it to an RS-232 to USB adapter which is also inside the meter. So all you have to do is plug the USB into the computer, and install USB virtual COM drivers onto the PC. Then voila, it appears as an RS-232 port. Labview might be using the same protocol, or it's own special dedicated protocol but you don't really care if you're using LabView.

So hook the meter up to the PC, install the virtual COM port drivers, set the meter to the right interface mode, and download, install, and run some free terminal software and it'll spit out a screen of numbers for you. Or install the Labview drivers (only one of the meters seems to have them) and use LabView. Easy peasy. Skim the manuals, look at the support software available in your links.
Last edited:


Well-Known Member
- Which interface is the best to use for beginners (I never even heard of GPIB and RS232 before!)?

Thank you all! :)
RS232 was one of the original means of communication from the start on just about all PC's and could communicate by modem over the phone line, PC's originally had the 25pin COM port, now reduced to the 9 pin D version, Many current PC's, although not showing any external 9pin COM, have a socket for the RS232 option on the MB.
IC's such as the MAX232 are still very popular for integrating with small microprocessors for data transmission.


Well-Known Member
Most Helpful Member
GPIB is also known as IEEE-488. It's a relic now but was once the standard where racks of scientific instruments were used. Up to 7 devices could be used on one interface, connected with stacking daisy-chained cables. It largely predates PCs and used computers that had the interface built in.

Interface cards are expensive and difficult to find. The is a GPIB - USB interface but it's an incomplete implementation, supporting limited devices.

USB is definitely the way to go.
Not open for further replies.

Latest threads

EE World Online Articles