How to read out data via usb

[FCHansa]

Hello,

i am trying to get the measurements of a dial indicator, "MarCator 1075", product of Mahr Co. via USB-Cable.

I installed all the drivers and MAX shows that its a COM-Device and its working properly. So i configured the settings: baud rate 4800, data bits 7, parity even, stop bits 2, apllied and saved the changes.

I tried those 2 attached VI's, but it doesnt work.

1. basic_serial_write_and_read.vi is the standard VI for USB-communication of NI.

2. Sylvac Read.vi is a VI the vendor send after i talked to him to inform me about the dial indicator. He said its a VI to get Data via RS232, but the problem is that i dont have a RS232-slot in my computer. In order to that i have to realize it via USB.

I think it doesnt work because there are no databits to be read out. When the dataflow arrives the "VISA-Read" theres is an error. This occures in both VI's.

Error -1073807339 occurred at VISA basic_serial_write_and_read.vi

Possible reason(s): VISA:  (Hex 0xBFFF0015) Timeout expired before operation completed.

Anyone who can help me with my issue??

thx in advance

best regards

[smercurio_fc]

---

@FCHansa wrote:

Hello,

i am trying to get the measurements of a dial indicator, "MarCator 1075", product of Mahr Co. via USB-Cable.

I installed all the drivers and MAX shows that its a COM-Device and its working properly.

---

How do you know?

---

I think it doesnt work because there are no databits to be read out. When the dataflow arrives the "VISA-Read" theres is an error. This occures in both VI's.

---

You have to look at the programming manual to understand how to use the device. In the "basic" VI the VI is sending out an *IDN? command. Does the device even accept that command? You can't send arbitrary commands to a device and expect a response. In the "Sylvac" VI there is no command being sent out. Rather, it the DTR line is toggled. Does this mean this triggers the device to send something? Is this what it says in the manual? If so, does it send out 9 bytes total, since that's what the VISA Read is programmed to read.

[ADagli]

Hello FCHansa,

have you installed the proper drivers?

Which version of LabVIEW are you using?

Which OS are you working on?

In the LabVIEW Example Finder you have a simple example how you can communicate to a USB HW via NI-VISA.

It's called "Basic TCPIP or USB VISA Write and Read - PDA.lvproj". Or another would be "Basic TCPIP or USB VISA Write and Read - Touch Panel.lvproj"

Have you configured your USB Device to a virtual COM interface?

Also please have a look to these links:

What is the Difference Between USB Raw Control and USB Raw Bulk?

http://digital.ni.com/public.nsf/allkb/400D6EAB5CFE1C6B86257395005F5D48?OpenDocument

USB RAW Controller

https://decibel.ni.com/content/docs/DOC-2022

Also, please follow the advises of smercurio_fc! As he said you need to know to which commands your Hardware is responding to.

Best regards,

[FCHansa]

hello,

thank you for your answers. 

Now i managed to get the values. I switched the dtr state in the Sylcav-Read.vi and now its working.

regards