I need to control and communicate with a loadcell - Mecmesin Multitest 2.5k - over USB/Serial - any ideas?

[drBen]

HELP!

I'm currently working on a project where i apply a force to a material - the (non-labview related) software that is provided with the tool (Mecmesin Multitest 2.5k) allows control but (obviously) I want to control it using LabView, as well as plot any data using LabView.

This question has come up several years ago on these forums, but there has never been a good answer. I'm adequate at using LabView for simple programming (loops, arrays, sorting data etc) but am a newb in most other respects - unless companies provide subVIs!

The tool currently uses a USB-serial connection (PC-end is USB). I believe I could use rs232-rs232, but someone in the dept said that doesn't always work, which could just mean the serial cable is naff. I would like it to work from USB however, as ideally something else is plugged into the serial port currently.

Can this be done? If so, can anyone help?

[Dennis_Knutson]

I don't understand your statement "I could use rs232-rs232". If the instrument has USB connection that emulates a serial port, then that is all you would need. An easy check is to see if you get a new serial port in windows device manager or MAX when you connect the instrument. So, that would be the first thing to do. After that, then you can start to think about communicating with it through LabVIEW.

[drBen]

Hi, thanks for replying. Sorry if I was unclear...

I mean the instrument has a serial port - so the cable from PC to instrument is a USB-serial cable. Is this possible to control? The PC obviously sees the instrument fine, as we can control it using the native/provided propriety Mecmesin software. How do I check if LabView can see it/how do i make LabView see this?

Please remember i'm a newb at this level of LV!!!

Thanks again for your interest 🙂

Ben

[Dennis_Knutson]

As I said, just go into MAX (Measurement and Automation Explorer). You can click on Devices and Interfaces and see your serial port.

[drBen]

Thank you so much for your help so far Dennis

I'd been in to MAX and was just getting an Error (stupidly didn't take a screen shot) which implied that MAX could see something on the port (COM3, by the way) but it couldn't communicate to it...

Turns out I had left on the Mecmesin software. I turned this off... unfortunately still no beans...

I rebooted the computer and turned off the instrument. Turned it all back on...

Success...

so I now know that MAX can see the instrument. Unfortunately I'm now stuck at the VISA test panel (I right clicked on the COM3 port) and I'm looking at a window with 4 tabs saying things like viSetAttribute, viWrite, viRead, viClear (which I assume are subVIs from VISA to control the instrument?)

Could you give me some clue as to what to try next to prove that there is some way of controlling the device?

Again, thanks for your help so far - i did say I was a newb in these realms!

Ben

[Dennis_Knutson · Accepted solution]

The next step is to open the programming manual for the instrument. Determine the commands that you need to send to the instrument and understand how the instrument sends information. You can use the VISA test panels for this or a program such as Hyperterminal. To send something to the instrument, you use a VISA Write (ViWrite tab) and to get data, a VISA Read (ViRead).

[drBen]

Thanks for all your help Dennis, I'll see how far I get with that.