MyRIO VISA Error -1073807192

Question

Hi Everyone,
My problem is as follows: my myRIO can successfully see a Hokuyo URG-04LX module that I've connected to the USB host port. However, when using VISA Open Resource, I receive the following error:
-1073807192: VISA:  (Hex 0xBFFF00A8) Access to the resource or remote machine is denied. This is due to lack of sufficient privileges for the current user or machine.
Online KBs suggest that this is a security issue to do with the IP address, but MAX shows that the myRIO's security settings allow communication on all ports.
So, at this point I'm stumped! Does anybody have any suggestions?
Further information:
The myRIO does not detect this kind of device by default, and I had to follow this tutorial to learn first how to get LabVIEW to recognise a connected ttyUSB device such as an FTDI chip, then deviate from the tutorial slightly so that it instead supports the USB Communication Device Class (ttyACM), which is the type of device class the URG-04LX adheres to.
The code I've used is as follows:
Within the /etc/mdev.conf file, underneath #typical devices, I've added the line:
ttyACM[0-9]*     root:tty 666
Within /etc/rc5.d/, I've added the file S10SetLnUSB provided in the tutorial, except any entries pointing to ttyUSB have been changed to ttyASM:
#!/bin/sh
#echo "==>Creating SymLnk to ttyACM0"
#ln -s /dev/ttyACM0 /dev/ttyS2
n=`ls
/dev/ttyS* | sort | tail -1 | tr 'S' ' ' | awk '{print $2}'`
num=`expr $n + 1`
ln -s
/dev/ttyACM0 "/dev/ttyS${num}"
Finally, the tutorial recommends using this command to recognise the added script:
#chmod a+x /etc/rc5.d/S10SetLnUSB
At this point the myRIO can successfully see the connected device.
Alex Thomas, University of Manchester School of EEE LabVIEW Ambassador (CLAD)
Solved!
Go to Solution.

Answer 1

Hi all,
Just a small update.
I've managed to successfully increase the level of visibility of the URG-04LX module within MAX. Originally, it was being treated as a generic 'ASRL3::INSTR', but with some tweaking I've managed to acquire a full reference to the specific device instance. In fact, I've managed to grab two!  This is shown below.
At this point, I'm not able to directly acquire a reference within the VISA resource list within LabVIEW, however I can directly interface the device via a string constant:
I'm now going to reformat the myRIO so that I can start this process again from scratch, so I can deduce exactly what sequence of operations needs to be followed. I believe that the tutorial on this webpage may be what managed it! Specifically:
Create a file called 47-hokuyo.rules, and place this file within etc/rc5.d/. The contents of the file should be as follows:
SUBSYSTEMS=="usb", KERNEL=="ttyACM[0-9]*", ATTRS{manufacturer}=="Hokuyo Data Flex for USB", ATTRS{product}=="URG-Series USB Driver", MODE="0666", SYMLINK+="sensors/hokuyo"
I then used the command #chmod a+x /etc/rc5.d/47-hokuyo to make the file executable.
This didn't seem to work immediately, however after following this KB, which recommends using the command #rmmod cdc-acm to stop Linux from blocking device access, it finally appeared. I'll double check this now.
Alex Thomas, University of Manchester School of EEE LabVIEW Ambassador (CLAD)