ASRL_WIRE_MODE

[Wolfgang]

I am not sure if I should ask here or better in the Instrument control forum, let's try...

Using VISA, at program startup I am querying all available ports (for access and properties). In order to distinguish between RS232 and RS485 I use the attribute VI_ATTR_ASRL_WIRE_MODE.

Surprisingly, the call returns VI_ASRL_WIRE_485_4 which I would assume means RS485. However, the port is RS232, this is confirmed by also reading the port description which says: NI PCI-8430/8 (RS232).... (in accordance with NI-MAX)

The software is developed with CVI 8.5 and now using VISA 5.4. Since I recently upgraded from VISA 5.3 I suspect some incompatibility, could it be...?

Since some other software is also running on the same computer the run time engine is CVI2013.

If it is a compatibility issue (VISA readme suggests so, i.e. compatible only with CVI9.0 and later), how should I design my software to find out - it's sort of stupid if code is broken by updating a driver.

Thanks!

[JaninaH · Accepted solution]

Hello Wolfgang,

I did some research and found out that this is a known issue and it should be fixed in the new VISA driver version 14.0 (it should be released with the new LabView in August).

However I am not sure whether this version will work with your CVI Version, there are no official information about it yet.

Have a nice day,

Janina Huether

[Wolfgang]

Thanks a lot!

1) Is it possible to downgrade the driver to the previous version?

2) Could you please drop me a note once the new driver is released - since it broke my measurement software it is sort of urgent.

3) Unfortunately this 'known issue' is known only to NI, I did not find it in any official document - I'd suggest to improve this situation, many thanks!

[JaninaH]

If you want to install an older VISA version, you have to uninstall it  ("Add/Remove Programs>National Instruments Software" and choose VISA to uninstall) and then install the older version.

The driver shall be released in the duration of the NIWeek 2014, but I can post it in here if it is available.

Kind regards,

Janina

[Wolfgang]

I can confirm now that after installing the new VISA driver version 14.0 the bug has gone