Problems adding virtual channels in Max

Has anybody had any problems adding new virtual channels to an existing DAQ OPC configuration? We have a working configuration using 99 tags and adding a further tag to bring the total to 100 causes an OPC server failure. Any help or clues would be appreciated.

Hi mak90,
There are no ways to change the sensor range and physical ranges
programmatically in Traditional DAQ. Under DAQmx, you have Scaling VIs,
Calibration VIs, Task VIs that allow you to change various settings in
MAX programmatically.
Please let us know if you have any further questions.
Best regards,
Nathan Yang
Applications Engineer
National Instruments

Similar Messages

Why does labview forget the connections to the virtual channels in MAX?

I create a bunch of virtual channels in MAX - some with double assignment to a single AI port.
Context - a digital output controls a MUX to switch the inputs into the AI ports of my USB-6361(BNC) DAQmx; thereby allowing me to double up on the number of AI ports I can access (switching every 5ms).
I can run the code without any troubles. I have now completed my hardware set up and and am now testing the integration with the code. This is where things become a little unstuck.
Problem: some ports, over time, start displaying erroneous data that is not correct. It is not until I delete the virtual channel and re-create it in MAX, does everything settle and work. This 'bad' data is seen in the MAX test panels tab and virtual channels tab.
What is going on - should I bite the bullet and program all port assignments (channels) within my code?
Am i mistakenly killing a link between MAX and the DAQmx?

natashw already told you that it's expected behaviour when you leave the analog input open. There are two aspects to this:
1) The analog input amplifier is a high impedance operation amplifier. It's minimal stray capacitance is high enough that it gets charged through very small leakage currents in the amplifier input stage, but the high input impedance doesn't allow those capacitance to discharge quick enough to stay at a defined voltage. So your input is usually very slowly floating to one of the power supply rails depending what transistor side has a slightly higher leakage.
2) You only have one analog to digital converter. To get multiple channels there is a multiplexer than connects the different input channels to this single ADC. When the multiplexer switches between from a connected signal to an unconnected signal those stray capacitance at the ADC amplifier input has been charged to a certain voltage from the connected channel. With only the internal impedance of the amplifier to discharge this capacitance after the multiplexer switched to an unconnected input, the ADC will simply see the voltage that the stray capacitance has been charged to.
Having a low impedance amplifier input would solve that problem but create many more problems that would affect the measurement accuracy significantly.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

How to make a virtual channel in MAX using DAQmx ?

I want to measure the CJC temperature on the TBX 1328 ( attached to SCXI 1121). I want to create a virtual channel in MAX using DAQmx. I have right clicked on DAQmx but there is no option for virtual channel. Ther is the option of 'Traditional virtual channel' which i dont want.
I used the VI to make the virtual channel but i want to knowhow to doit inMAX.
thanks

Here are 2 ways that you can create a DAQmx channel that appears in MAX.
1) In MAX, right click on "Data Neighborhood" and select "Create New...". Then click "NI-DAQmx Global Channel" (or "NI-DAQmx Task" -- a task contains the channel(s) and triggering/timing information) and click "Next". This launches the DAQ Assistant that will guide you in creating the channel or task.
2) In LV, place a NI-DAQmx Global Channel control on your panel or constant on your diagram. Right click on the control/constant and select "New Channel(DAQ Assistant)..." (Note: You can do the same from the NI-DAQmx Task control/constant to create a NI-DAQmx Task.)
Deborah

Writing in sensor calibration data to my virtual channels in MAX using Labview.

System consists of a few pxi6713 cards, a 6527 digital input card and some scxi cards (1520, 1104c, 1125).
Every 3months or so we run a calibration on the testing stand which uses these cards, and the sensor ranges and physical ranges listed in MAX has to be manually entered each time.
I am looking for a way to do this automatically. This may be a problem, but we are using NI-DAQ legacy (perhaps if absolutely necessary we could goto daqmx).
I have figured out howto read virtual channel information from max correctly, but I have no understanding of trying to write calibration information to the virtual channels.
Any help is greatly appreciated!
Thank you!
jacob

Hi mak90,
There are no ways to change the sensor range and physical ranges
programmatically in Traditional DAQ. Under DAQmx, you have Scaling VIs,
Calibration VIs, Task VIs that allow you to change various settings in
MAX programmatically.
Please let us know if you have any further questions.
Best regards,
Nathan Yang
Applications Engineer
National Instruments

Duplicating a CTR Global Virtual Channel in MAX does not update the CO.Pulse.Term setting

Hi,
Here is the issue description:
MAX version: 4.6.2f1
daqmx: 9.0.2
Hardware: cDAQ-9178 , NI-9474 Digital output.
For this module one has:
crt 0 out <--> PFI3
ctr 1 out <--> PFI7
crt 2 out <--> PFI1
ctr 3 out <--> PFI5
1. In MAX create a Global Virtual Channel as a CTR output on ctr0.
2. use the Duplicate in the menu to create a second counter output. Change its name, and change it ctr output to ctr 1 OUT.
3. In MAX, the Pulse Output Setup pane should reflect the change by showing the ouput terminal pointing to the proper PFIi
4. Export the settings to an INI file, and look at the CO.Pulse.Term settings for both CTR channels: they will both appear with the SAME PFIi !
5. Using LabVIEW Write a vi that generate pulses on these 2 channels , you will get Error -89137 saying a PFIi resource is already used. If you look at the Task property CO.Pulse.Terminal, it returns the same for both tas, which is the same error seen in the ini file.
Can someone at NI check this? Thx.
Laurent
PS: I posted this message in the LabVIEW board as I did not find one for MAX
Solved!
Go to Solution.

Hi Laurent,
I verified this behavior with DAQmx 9.1 and a simulated device. I will file this as a Corrective Action Request (CAR). Creating the channels manually works correctly and produces the correct .ini file. Sorry for any inconvenience this may cause.
Regards,
h_baker
National Instruments
Applications Engineer
Digital Multimeter Resources

Virtual channel in max don' work whith pci6071

hello I configure 32 channels in max then when i test the first channel it' s ok.And when i test the second channel in max it don't work the light is red and for other channel is the same, if sommeone have a solution thank you.

Hi,
Can you be more precise. Which board do you have? Which driver?
Did you test your channels during the configuration? The led is red : is there an error message?
Regards
DD

How do I import Traditional NI-DAQ Virtual Channels and MAX 3.1

I installed Labview 7.1 on a new machine and the tools option in MAX 3.1 does not have the option to import traditional NI-DAQ configurations.

If you have support for Traditional NI-DAQ installed, you should have the option to open a configuration file from: Tools>>Traditional NI-DAQ Configuration>>Set Active Configuration. You can check the installation of Traditional NI-DAQ under the Software tree in MAX.
Hope this helps.
Regards,
Erin

DAQmX create virtual channel execution time

Hi,
I am using DAQmX Create Virtual Channel for 70 different Digital Output. It took 35 seconds to execute the DAQmX Create Viryual Channel VI.
What are the steps to make the execution faster.
Valliappan.M

Have you tried creating a global virtual channel with MAX?
André
Regards,
André
Using whatever version of LV the customer requires. (LV5.1-LV2012) (www.carya.nl)

Virtual channels with 6602 counters

Can I define 6602 counter source and gate inputs as virtual channels with MAX 2.1?

Hello;
You can't do that with MAX at this time yet.
Filipe

Is it possible to display in a front panel indicator the units name (for instance, N "Newtons" or ºC) from a virtual channel that you previously defined using MAX?

If possible, how can I do it?
Thanks in advance With LabVIEW 6 it is clear that we can display the DAQ channel name of previously defined virtual channels, so it seems to be possible that we would be able to access to other information defined in MAX as channel units name...
Thanks

Yes it is possible.
Locate the LLB:
LV folder\vi.lib\daq\dqchnutl.llb
There you find useful vis to handle virtual channel.
The Get DAQ ChannelNames.vi return also the channel units

Problems with premium channels added

I've been having nothing but problems trying to add channels to my package. I went online yesterday & saw they were doing the 50% off for 12 months promo for their different movie packages and I went ahead and added the Showtime/Starz for $8.50/month. It never came on last night. I called and was told that my local center is probably closed & that it would work in the morning. This morning it still didn't work so I called the # given to me last night (1-888-978-2176) which got me nowhere. I was told my acct# is invalid and that I'm not even eligible for Fios in my area (which I've had for a year & a half.) After getting my address wrong several times, I was told I'd need to be called back (which I still haven't been.)
I then called 1-800-VERIZON and was told he didn't see anything about me adding these channels. I asked if he could go ahead and add them for me then and he said he could but it would be $9.99. I stated how it was $8.50 online and he said maybe it was an online promo and that he couldn't give it to me. I was then told that I could have Showtime OR Starz but not both. I told him that when you go to upgrade online Showtime/Starz for $8.49/month was clearly an option to which he really didn't seem to care and said that's not available in my area and I'd pretty much have to get each one seperately.
Sorry, part of this is to vent due to my frustration but another part is to see if this sounds right since I feel like I get a different story/response everytime I call customer service. I really wanted Showtime/Starz but I told him if this was the case to just sign me up for Showtime. Also if this is actually the case, that package should be removed from the options on the website. I also should've been notified that my online order had been cancelled.

I have the opposite problem - premium channels keep getting added without my permission or intention. I have a 4-yr-old son and I think he is playing with the remote while I'm at work. Apparently the FIOS STB will let you subscribe to any premium channels just by clicking a few buttons. So far I have had HBO and the Playboy channel and some Chinese channel (nobody speaks Chinese here) and something else.
I switched over from Comcast to Verizon's double-play last month, and now I'm really starting to regret it. It has been nothing but a headache, from adapters that don't work to this.

Is CJC compensation automatically applied to Virtual Channels created with MAX?

I have a SCXI 1000 chassis, a SCXI 1102 module and a TC 2095 terminal block. I am configuring virtual channels with the names TC(n) where n is the channel number. When I configure the virtual channel, I am selecting 'built-in' CJC. The question I have is:
When I reference the virtual channel from my DAQ application, is the data I receive already cold-junction-compensated, or do I have to read the CJC voltage as a separate channel, and apply the correction factor manually on my block diagram (like we had to do in the old days)?
I gather that the data that I read, which is obviously scaled to engineering units, is, indeed, cold-junction compensated, but I would like to be certain that t
hat is the case. Thanks.

Wes;
You are right. That is the way it works. If you specify the CJC compensation in MAX when creating a Virtual channel, to be the built in CJC, the data you get is going to be CJCed already.
Hope this helps.
Filipe

Is There a way to programmatically extract global virtual channel info from max?

I have a group of DAQmx virtual global channels setup in MAX and I would like to be able to programmatically extract the physical channel information to be included with the data file. In the past I have been able to use traditional NI-DAQ channel utility vi's to accomplish this, but they only see traditional NI-DAQ virtual channels and not DAQmx virtual channels. Is there a group of vi's for extracting DAQmx virtual channel information? I'm using Labview 7.1 with a Windows XP OS.

Paul,
I can access basic properties using the approach you described, but do you know how to get the units from the global virtual channel? Say I had a general appliance for reading in load cells, and I wanted to have the axis labels in a graph show the units of whatever load cell had been selected.

Computer crashes when using virtual channel custom scales.

I am using a PXI-1045, which is connected to my computer via a MXI-3, to hold 3 PXI-6115 cards as well as several other cards. I have been using virtual channels for the nine input channels I am looking at. When I added custom scaling to one of the virtual channels my LabView application crashed the next time I ran it. If I remove the scaling it goes back to working fine, but when I add it back in it crashes again. The crash causes the computer to automatically restart, but on one of the runs I got a "Fatal Internal Error: 'memory.cpp', line 593" message before the computer restarted. I've tried reinstalling MAX and updating some drivers, but nothing seems to help.
Thank you.

Still having the same problem. Ever the optimist, I submit the following info.
Error window screenshot can be found here: https://dl.dropboxusercontent.com/u/22465174/safari/safari_fail_01.JPG
Enent log entry can be found here: https://dl.dropboxusercontent.com/u/22465174/safari/safari_fail_02.txt
Version info can be found here: https://dl.dropboxusercontent.com/u/22465174/safari/safari_fail_03.JPG

Drive Redirection virtual channel hangs when copying a file from server to client over RDP 8.1

Problem Summary:
A UTF-8 without BOM Web RoE XML file output from a line of business application will not drag and drop copy nor copy/paste from a Server 2012 R2 RD Session Host running RD Gateway to a Windows 7 Remote Desktop client over an RDP 8.1 connection and the Drive
Redirection virtual channel hangs. The same issue affects a test client/server with only Remote Desktop enabled on the server.
Other files copy with no issue. See below for more info.
Environment:
Server 2012 R2 Standard v6.3.9600 Build 9600
the production server runs RDS Session Host and RD Gateway roles (on the same server). BUT,
the issue can be reproduced on a test machine running this OS with simply Remote Desktop enabled for Remote Administration
Windows 7 Pro w SP1v6.1.7601 SP1 Build 7601 running updates to support RDP 8.1
More Information:
-the file is a UTF-8 w/o BOM (Byte Order Marker) file containing XML data and has a .BLK extension. It is a Web Record of Employment (RoE) data file exported from the Maestro accounting application.
-the XML file that does not copy does successfully validate against CRA's validation XML Schema for Web RoE files
-Video redirection is NOT AFFECTED and continues to work
-the Drive Redirection virtual channel can be re-established by disconnecting/reconnecting
-when the copy fails, a file is created on the client and is a similar size to the original. However, the contents are incomplete. The file appears blank but CTRL-A shows whitespace
-we can copy the contents into a file created with Notepad and then that file, which used to copy, will then NOT copy
-the issue affects another Server 2012 R2 test installation, not just the production server
-it also affects other client Win7 Pro systems against affected server
-the issue is uni-directional i.e. copy fails server to client but succeeds client to server
-I don't notice any event log entries at the time I attempt to copy the file.
What DOES WORK
-downgrading to RDP 7.1 on the client WORKS
-modifying the file > 2 characters -- either changing existing characters or adding characters (CRLFs) WORKS
-compressing the file WORKS e.g. to a ZIP file
-copying OTHER files of smaller, same, and larger sizes WORKS
What DOES NOT WORK?
-changing the name and/or extension does not work
-copying and pasting affected content into a text file that used to have different content and did copy before, then does not work
-Disabling SMB3 and SMB2 does not work
-modifying TCP auto-tuning does not work
-disabling WinFW on both client and server does not work
As noted above, if I modify the affected file to sanitize it's contents, it will work, so it's not much help. I'm going to try to get a sample file exported that I can upload since I can't give you the original.
Your help is greatly appreciated!
Thanks.
Kevin

Hi Dharmesh,
Thanks for your reply!
The issue does seem to affect multiple users. I'm not fully clear on whether it's multiple users and the same employee's file, but I suspect so.
The issue happens with a specific XML file and I've since determined that it seems to affect the exported RoE XML file for one employee (record?) in the software. Other employees appear to work.
The biggest issue is that there's limited support from the vendor in this scenario. Their app is supported on 2012 R2 RDS.
What I can't quite wrap my head around are
why does it work in RDP 7.1 but not 8.1? What differences between the two for drive redirection would have it work in 7.1 and not 8.1?
when I examine the affected file, it really doesn't appear any different than one that works. I used Notepad++ and it shows the encoding as the same and there doesn't appear to be any invalid characters in the affected file. I wondered
if there was some string of characters that was being misinterpreted by RDP or some other operation and blocked somehow but besides having disabled AV and firewall software on both ends, I'm not sure what else I could change to test that further
Since it seems to affect only the one employee's XML file AND since modifying that file to change details in order to post it online would then make that file able to be copied, it seems I won't be able to post a sample. Too bad.
Kevin

Problems adding virtual channels in Max

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