AI Continuous Scan.vi and channel inputs

It seems that I am having difficulty connecting a DAQ Channel Name Constant to the channel input of the AI Continuous Scan.vi. Anyone know why the two data types are different?

Currently you are connecting a string(DAQ Channel Name constant) to a terminal that requires 1-D array of strings. I'll recommend you introduce the Build Array function between the two terminals. In case you have more than one DAQ Channel Names, all you need to do is to adjust the Build Array function to the number of your channel names.

Similar Messages

Difficulty getting Sound input configure and sound input to read more than 2 channels

I need multichannel audio input for my project. I can't seem to read more than 2 channels of my audio interface.
The interface Im using is an Alesis Multimix8 USB 2 mixer and and audio interface. This supports 10 channels in and 2 out. With other software I can read all input channels simultaneously without any difficulty. When I specify the sound input configure and sound input read, to read more than 2 channels any extra channel is a blank signal. Im using Labview 8.5 here.
Solved!
Go to Solution.

Take a look here
http://forums.ni.com/t5/LabVIEW/Play-waveform-express-vi-list-devices-on-front-panel/td-p/1559336
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

Scan scan bar on the printer is continuously moving back and forth.

The printer is connected via USB to a computer using Vista and also used remotely by a MAC, IPad, and IPhones.
The scan bar on the printer is continuously moving back and forth, I ran the HP Print Scan Doctor and it found no problem.
I can print, copy, and scan but the motion of this piece on the device will not stop.
No change to the issue occurred when I turned the printer off, waited several hours, and turned it back on.

Hi @GGx3,
Welcome to the HP Forums!
I noticed that the scan bar on your HP Officejet pro 6830 printer is continuously moving back and forth. I am happy to look into this scanning issue for you!
First, I would recommend a hard reset, by going to this post, How to perform a Hard Reset, by @Rich1. it is important that the printer's power cable is plugged directly into the wall outlet, and not a surge protector. Please, see this article, Issues when Connected to an Uninterruptible Power Supply/Power Strip/Surge Protector for more information. This applies to Inkjet printers as well.
After the hard reset, I would go through this guide, The HP Printer Does Not Turn On or Respond When the Power Button is Pressed, and watch this video:
(Even though the guide title may not match your issue, I believe the solutions will help.)
The last step I would do is to also make sure your printer's firmware is up-to-date. Getting Printer Updates for HP Officejet 6810 and Officejet Pro 6830 e-All-in-One Printer Series.
Hope this solves your problem, and have a good day!
“Please click the Thumbs up icon below to give me a virtual high-five for responding.”
RnRMusicMan
I work on behalf of HP
Please click “Accept as Solution ” if you feel my post solved your issue, it will help others find the solution.
Click the “Kudos Thumbs Up" to say “Thanks” for helping!

Does NI-6008 have both scan and channel clocks ?

Does the NI-6008 have both scan and channel clocks whose rate can independently be set in LabVIEW ? I would like to acquire say 100 samples on one channel at 10 kHz and repeat this at 10 Hz rate. So 100 samples would be acquried at a 100 usec interval period (channel clock), then there would be a gap in time where no samples are acquired, then this process repeated again 100 msec (scan clock) later.
Steve

SteveP,
"Does the NI-6008 have both scan and channel clocks whose rate can independently be set in LabVIEW ?"
Yes and No. You can set the sample rate (scan rate) on the
USB-6008/6009 but you cannot set the convert clock rate (channel clock)
on the USB-6008/6009.
Also, you cannot use an external clock with the USB-6008/6009 (in both the DAQmx driver and the DAQmx Base Driver).
The lack of both these feature limits you to one option to complete the task you want.
If you want to take 100 samples at 10kHZ every 100msec (10Hz) then you
will have to do a conintuous acqusition at 10kHz and use post
processing to drop the samples you do not need.
I hope this helps,
Lorne Hengst
Application Engineer
National Instruments

Why is AI Continuous Scan.vi causing LabView 6.0 to run at such a slow rate?

I am working on a 6 degree-of-freedom load application system. It is forced controlled by pneumatic actuators operated using servovalves in a closed loop force controlled feedback system. The machine is instrumented with displacement (LVDTs and RVDTs) and force transducers (load cells and strain gage torque cells) so I can obtain measurements of all degrees-of-freedom (3 rotations and 3 translations).
The user interface to operate the machine has been designed on LabView 6i. I know this is an outdated version - but half of the code was written previously, so I wanted to simply update and add to its functionality. It runs on a Dell Optiplex GX260 Computer running Windows 2000.
What I do with LabView is input a control file that contains a series of clutch activations, loading parameters, and data collect on/off options to manipulate the machine. This seems to run very well and FAST (about 25 seconds for 15 lines of code). However, when I choose to acquire the data from our load and displacement sensors - this becomes VERY slow (about 12 minutes for the same 15 lines of code). I have been trying different things out with the code to no avail. First, everything that can be is running in parallel loops. Second, I disabled loops that aren't required when we are running the control file. Third, I omitted all signal processing that occurs (this is where we convert the voltages from the load and displacement transducers to actual force and distances using calibration coefficients). However, nothing is speeding up the data acquisition.
Currently we have two DAQs (a PCI-6023E and PCI-6040) for data acquisition. I am only currently using the PCI-6023E board. I am using the NI provided .vi AI Continuous Scan (waveform).vi. I would like to sample at 100 Hz (scan rate) and have a buffer size of 1000 and a number of scans to read at 10. Prior to the data acquisition the user chooses what load and displacement channels he/she would like to acquire data from. It is rare that more than 2 channels are being acquired from at a single time (usually a single load and single displacement channel). Only the user selected channels are passed to AI Continous Scan (waveform). I have the iteration input variable wired to the iteration terminal of my while loop, so AIConfig and AIStart only configure the first time.
So how this works is the control file looks for a "data_collect" phrase set to "on" and then the parallel data acqusition loop is activated. The file control loop is matched to the data acquisition loop using a "Wait on Occurrance."
I am attaching several VIs. The main executable I run is called KBiii_Esther.vi. This runs many subVIs to configure the experiment, etc. The file control is activated in the file control loop and runs using the do_file_control.vi. Finally, the data acquisition is activated in a seperate parallel loop and runs the do_acq_wave.vi. This is where I believe the problem lies.
Questions:
1) Does anyone have any ideas why the data acquisition is slowing everything down? AND do you have any ideas or suggestions as to how to fix this problem? Is it the reading of the data or the writing to a spreadsheet that slows everything down?
2) Does anyone have any suggestions for better buffer size and number of scans to read values to optimize performance?
Thanks in advance.
Solved!
Go to Solution.
Attachments:
KBiii_Esther.vi ‏488 KB
do_file_control.vi ‏324 KB
do_acq_wave.vi ‏249 KB

To many sub VIs could not be found so I can not give you more than some advises. But I see that you run all your loops at full speed. I do not think it is very wise. Insert the "wait (ms)" functions in all while loops, but not the loops handling the daq functions. Since they are controlled by a occurrence. In Loops handling user input only you may set the wait time as high as 500ms. In more important loops use shorter time.
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

How to combine Digital Output, a delay and Analog Input in a fast loop

I need to develop a process loop that runs at least at 250 Hz that performs a Digital output, than a delay of 50 microseconds and than an analog input of all the channels. All will be done using ATI MIO 64E3 card. Of course, the acquired data will be processed, displayed and saved. The loop will be running for several minutes until user stops it.

The fastest and most precise timing will occur if you use hardware timing. You can apply hardware timing to analog input on the E Series boards, but not the digital lines. Let's focus on the analog input first. Continuous waveform scanning uses a scan clock, which can be the board's internal one or an external one which you apply. If you want to scan all the channels 50 microseconds after a digital rising edge, then you need an external signal to signify that scan clock.
The E Series boards also have 2 counter/timers onboard that you can use for this purpose. You can set up a retriggerable pulse generation operation, where the counter receives a trigger and then on the user specifications, produces a pulse. You can have that route to the analog input scan clock.
The trigger signal for the counter is that digital pulse. As I mentioned earlier, there is no hardware timing for the digital lines on an E Series board. We do have other digital boards (653x family) that have hardware timed operations if precision is important. If you are satisfied with software's resolution (in the milliseconds), then you can call the E Series board digital function in a loop with a software timer. That digital line can route to the counter to act as the trigger.
So, on the programming side, you can have three separate and independent operations in parallel. One is for the digital function to output on that line every so often. Another is for the counter set at the retriggerable pulse generation. The last is for the analog input. I will describe this in terms of LabVIEW, but it can be done in a similar fashion with the NI-DAQ function calls or Measurement Studio.
The digital examples are in the LabVIEW >> Examples >> Daq >> Digital >> E-Series directory. The Generate Retriggerable Pulse example is in the LabVIEW >> Examples >> Daq >> Counters >> DAQ-STC directory. The E Series boards use the DAQ-STC timing chip.
Go to the LabVIEW >> Examples >> Daq >> anlogin >> strmdisk.llb directory and start with the Cont Acq to Spreadsheet File. This shows how to continuously acquire data and stream it to disk while displaying the data on a chart. Streaming to disk is the efficient way to save data while you are acquiring, as it eliminates the overhead of always opening and closing the file through the iterations of the loop. This saves to a file that can be opened by other applications (Excel, Word, etc.), but it is not as fast as writing to a binary file, which must be opened and read back through LabVIEW. However, for your ~250 Hz rate, it should be fine. Then, go to the LabVIEW >> Examples >> Daq >> anlogin >> anlogin.llb and look at the Acquire N Scans -ExtScanClk example. This shows how to apply the scan clock. Here, the AI Start that you saw in the previous example is replaced by 4 VIs (3 AI Clock Config's and the AI Control). Make those changes to the first example and then add a constant 0 to the AI Control parameter for total scans to acquire. That specifies the continuous operation. The File >> VI Properties >> Documentation menu item of the example describes the physical connections.
If you aren't using LabVIEW, use the NI-DAQ User Manual and the NI-DAQ Help file installed on your machine. You can look at your AT E Series User Manual at the http://www.ni.com/manuals pages for more information on the hardware. Also, if you want to route those signals internally on the board, you can find some entries in the KnowledgeBase at the http://www.ni.com/support pages.
Regards,
Geneva L.
Applications Engineering
National Instruments
http://www.ni.com/ask

How do I synchronize a 250x250 Scan AO and AI with hardware clocks?

Hi,
I am building a Scanning tunneling Microscope STM which requires a 250 by 250 pixel scan with a delay of about 1ms between pixels. I want to start the scan with a software trigger. The scan entails outputting an x and y value using two AO channels , wait about 1ms then read a tunnel current analog input value at that position, store it in an array and repeat till done. The array will then be plotted using an intensity graph.
As an option, I would like to plot a single line of the scan as it is completed to allow operator monitoring as the scan is produced. I have programmed this in sw using nested while loops but the overhead is too great for 1ms pixel sample times.
I have found a close solution in forum under the AI delay following an AO that used a hardware trigger to start process : See" AODelayAI.vi"
I have a PCI MIO 16E-4 DAQ board and am using LABVIEW 6.
PS: Is there any discrete that is generated by an AO which can be used to trigger an AI or a counter?

I have several follow up questions:
Q1)Re your suggestion to use the AO to trigger a counter : What signals sources from AO processes are available to route to the counter trigger? I have no external sources.
Q2)
What about this alternative proposal for a single AI read at each point?
a) use counter0 to generate a single pulse (about 1ms wide) , low phase 1, hi phase 2. Start counter with SW.
b) set AI trigger to output of counter0. Trigger on hi to low edge.
c) set AO trigger identical to AI trigger. Trigger on low to hi edge.
Read
Set AI scan rate and number of scans to match the AO scan parameters with timing based on internal scan clocks.
Q3)I foresee a possible need to make 20 to 100 AI samples at each (x,y) point for post processing averaging of noise effects. What modifications are needed to AI trigger scheme to make these reads to a buffer and read the buffer without adding significant software overhead?
Thanks again

During continuous scanning thermocouples with a SCXI 1120 module is the cjc reference read each scan?

Did the developers of the DAQmx drivers improve the temperature scan capability of the SXCI 1120 module over the methods used in the traditional drivers?
When using the SCXI 1120 module for temperature measurement and in the continuous scan mode with traditional drivers the cold junction reference was only checked on the initial start of the scan. In order to maintain accuracy it was necessary to restart the scan.
For the most part I have switched to the 1125 module for thermocouple measurement but I need to use some 1120 modules on a test stand now and I will be using the DAQmx drivers on these. I was in hopes that with the DAQmx drivers this behavior was corrected.
I can conduct testing to determine this but would like to know ahead of time if this is still an issue.
Thanks

Thank you Ben for the answer.
I checked the article you referenced appears to me that I will be adding the physical address in the channel strings then do the voltage to temperature conversion and then correct the appropriate channels associated with the cjc in question. I will also need to adjust some on board jumpers for the SCXI 1120. If I am wrong please correct me.
If scanning the physical channel is possible as suggested in this article, would it not be possible to create the channel as a virtual global channel and reference it as the cold junction in Max? Then the temperature adjustment could be done at this level of acquisition rather than having to sort this out in the LabVIEW program. This takes me back to the days with LabVIEW 4.0 before we had the virtual channels and when we had to handle the temperature conversions and other scaling ourselves. Again if I am incorrect please let me know, for I would like to use the method recommended in the article if I don't have to perform all the calculations in the application.
Just wondering if anybody reading this has actually used this method. If so, how did it work for you?
I may end up building a start up routine testing for 1120 modules being used for thermocouple measurement then if found run a stop and restart scan every 5 minutes to prevent large errors from being introduced.

Error: Could not continue scan with nolock due to data movement, DBCC proccache will clear the probelm

SQL Server: 2008 R2 SP2
Before describing my problem, I have gone via the forum, there is no view or functions inside my stored procedure
When running a particular stored procedure inside crystal report, the error " Could not continue scan with nolock due to data movement" comes once every few weeks. After I clear the query cache plan, it works again for few weeks and the problem
comes again. During these few weeks, there is no restart or query plan clearing.
If I run the stored procedure inside SSMS, where the SQL statement is copied and pasted from SQL profiler during crystal report run, there is no error.
I discovered running in SSMS and crystal report generate 2 different query plans even I copied the SQL from SQL profiler, I have actually saved the query plans. Unfortunately, this forum does not accept attachments, or otherwise I will post my query plans
here.
There is one thing I notice about the query plan is during nested loop operation, there is a warning "no join predicate". I don't use any views or UDF in the statement, nor did I use pre-1992 ANSI join syntax. However, I did use table variables.
My guess is whether this will cause " Could not continue scan with nolock due to data movement", after I clear the cache, I run crystal report again, and I look at the plan again, the "nested loop no join predicate" warning is gone.
Running this stored procedure took 1 second maximum, even when this error is popping up, it pop up within 1 second.
DBCC checkdb has been run
The same stored procedure running by crystal report in a SQL 2008 (non r2) live environment has no problems, so I am thinking this is R2 specific problems.
The "nested loop no join predicate" error SQL statment is below, no views, no udf, but table variables
INSERT @ChequeAccount
SELECT       PS.PaySummaryID, PS.EmployeeID, PS.CostCentreID,
           (PS.GrossPay   + PS.LumpSumA + PS.LumpSumB   + PS.LumpSumD+ PS.LumpSumE+ PS.ETP+ PS.PaymentsAfterTax   - PS.DeductionsAfterTax
- PS.Tax- PS.ETPTax   + PS.TaxRebate) * -1 AS Amount,
           CGLM.GLAccountID
FROM Pay_Summary PS JOIN Input_Sheet ISH ON PS.InputSheetID = ISH.InputSheetID AND ISH.PayrollID = @binPayrollID
AND PS.PaySummaryID NOT IN (SELECT PaySummaryID FROM @ChequeAccount)
JOIN Payroll P ON P.PayrollID = ISH.PayrollID AND P.EmployerID = @binEmployerID
JOIN CustomGLFixMapping CGLM ON CGLM.EmployerID = P.EmployerID AND CustomGLFixMappingNameID = 1 AND CGLM.CostCentreID IS NULL

The error Could not continue scan with nolock due to data movement can occur when you use the NOLOCK table hint, or use the command SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED. That is, so-called dirty reads. The error is not related to the
query plan per se, but when scanning a table, the storage engine will use an IAM scan rather than following the clustered index. If there is simultaneous activity, the storage engine may detect this and abort the operation to avoid returning incorrect data.
Or it may not detect it, and return uncommitted data or fail to return committed data.
All of these effects are transitory and they will not show up when you are alone on the system, only when there is concurrent activity in one or more of the tables in the query.
Using dirty reads is a risky business for the reasons explained above, and it takes careful analysis to understand whether you can live with the errors you can get from a particular query. The error about data movement can be handled: trap the error and
resubmit the query. But what about spurious incorrect results?
If you believe locking to be a problem, you should consider setting the database to READ_COMMITTED_SNAPSHOT
and take out all use of READ UNCOMMITTED/NOLOCK. When the database is in READ_COMMITTED_SNAPSHOT, readers read from the snapshot and only see committed data without blocking writers. This has some other effects like requiring a bigger tempdb,
and there is a risk for other types of concurrency errors, but they tend to be smaller risks.
I discovered running in SSMS and crystal report generate 2 different query plans even I copied the SQL from SQL profiler,
This is because SSMS by default runs with SET ARITHABORT ON. I discuss this in more detail in this article on my web site:
http://www.sommarskog.se/query-plan-mysteries.html
However, as I said, this problem is not related to the query plan as such, although some query plans are more susceptible to this error than others. (All plans are suscpeitble to produce incorrect results).
Erland Sommarskog, SQL Server MVP, [email protected]

Rename of Business systems and channels in PRD system

Hi all,
I am doing a rework of some scenarios in PI. I will rename business systems and channels.
When we move the new objects to Prduction and activate what is the best order to stop processing in PI before the switch over.
Is it
1)Stop PI inbound queues.(Deregister queues)
2)Check all outbound queues are empty.
3)Stop outbound queus (Deregister queues)
4)Stop all channels
5)Import all new objects
6)Delete old configuration and business systems and channels.
7)Activate all new configuration.
8)Activate all channels.
9)Register all queues.
10)Check all sender systems for failed (eg Outbound IDoc) and resend.
Have i missed anything?
What is the best way to handle sender for the following adapter types(HTTP , Proxy, RFC, SOAP)
Thank you for your input.

Hello,
The following note provides details on this procedure:
#870864 Starting and Stopping an XI 3.0 / PI 7.0 System
For 7.1:
http://help.sap.com/saphelp_nwpi71/helpdata/EN/12/5dd23aaad7b3408dde3c1577fda5b3/content.htm
Kind regards,
Sarah

How to define in different controls device and channels in a DAQmx function?

Hi,
I need to build a vi that permits the user to change the device of a DAQmx acquisition system, although I don't want that the user modify the input channels. I`d like to know if it is possible to define in different controls device and channels.
[]´s
Juliana

Hello Juliana,
What you would like to do is possible with some simple string manipulation. First you will need a Device Name constant from the DAQmx >> Advanced >> DAQmx Constants & Property Nodes palette. Right-click on the constant and turn it into a control. Then, use a concatenate strings function to join the device name with the rest of the characters you need to define your input channels. Wire the output of the concatenate strings VI to your DAQmx Create Channel VI.
Let me know if you have any questions on this.
Thanks,
Laura

Problem scanning for missing channels

Hi all.
Trying to scan for missing channels, mainly BBC2, and get as far as 72% - 3 mins reamining and the setup freezes.
I did contact Baombay Hight St., yesterday, but could hardly understand to bloke. He did tell me to do a couple of things to the box, but I couldn't make him understand that I am disabled and could n't get to the back of the box. I also tried to explain to him that I didn't know when I was going to see anyone who could help, as I live on my own and vary rarey see anyone who could help.
Any one any solutions?
Thanks.

Hi stokkers,
Does you STB freeze completely ? No response to remote control ?
A quick suggestion would be to try it again without the network cable connected.
Let us know if it helps.

Multi Channel Input on Recei

http://img202.imageshack.us/img202/586/5pchinputlarge9cj.jpg[/img] width="300" alt="Image Hosted by ImageShack.us" >
Ok I know that for the front and rear I would use a 3.5mm stereo to RCA but for the center/sub channel what should I use? Should it be a 3.5mm mono to RCA or something different or can it be a regular stereo red and white one?
Btw how much does this degrade the quality of the sound? I hoping that this method with the multi channel inputs and nice home theater speakers sounds better than a PC speaker system like the 5500.

My setup is similar to yours.
- I have the 5. channel analog outputs of my X-Fi goes to the 5. multi-channel inputs of my preamp-processor. This setup alllow me not only to play my ripped music in 5. also allows me to play DVD-audio disc. You can also play DTS/DD encoded movies as well as long as you set the DD/DTS decoding option to off (internal decoding) in the creative console mixer.
Advantage: Can use the X-Fi CMSS-3D to get 5./7/ expansion
2- I also have the SPDIF output of the X-Fi goes to one digital coax input of my preamp-processor. This setup gives me the same processing as the above except the playback of DVD-audio disc.
Disadvantage: SPDIF will ouput only in stereo, you will need to use the receiver processing modes(Dolby prologic I/II, Neo6, Stereo 5/7) to get 5./7. expansion
For me connection 2 is the better choice for playback mode except DVD-audio, the reason is my preamp processor is a $4K unit with the highest (Audiophile) quality DACs, plus I have the flexibility of setting the bass-management of this unit independently. Plus, I have a multitude of processing modes on this unit such as : DPL-IIx, Neo-6, 5./7. Music etc... to expand a 2 channels signal into 5./7.
I can see you have a digital coax input on your receiver, just buy a mono 3.5mm to coaxial convertor. Connect the 3.5mm SPDIF end to the X-FI SPDIF flexi-jack, and the Coax digital end to your receiver Digital coax in. With this connection you need to set DD/DTS decoding on the X-Fi to ON (External decoder).
http://www.ramelectronics.net/html/RCA-mini-spdif.html#rcabncMessage Edited by BrokenOath on 2-8-2005 0:7 PM

Rss; item and channel glitch

Hi,
Thanks so much for the previous input.
Now- I went to ensure the rss is accurate through feedburner and I get this Issue/Problem ...lol.
[This is bit strange, because previously the rss was fine since january up until recently.]
rss feed:
http://www.spheresofessence.com/rss/empodcast.xml
Below is the Error Message:
Sorry
This feed does not validate.
line 25, column 1: Undefined itunes:category element: item (8 occurrences) [help]
<item>
^
line 114, column 2: XML parsing error: <unknown>:114:2: mismatched tag [help]
</channel>
again, I tried adjusting things exactly like the tech specs.I tried both space between each item and space between last item and channel and with no spaces..still didn't validate in feedburner.
What is not accurate?
Any help or suggestions would be appreciated.
Thanks!! :-D
mystic

I had this same problem, but it wasn't an issue with the "<item>" tag -- as I had thought for the last hour or so.
Looking immediately above the <item> in my code, and comparing sample text side by side, I realized that I had improperly closed (or failed to close) the tag above.
In my case, it is the <itunes:category> tag, which much be closed with an </itunes:category> tag ... or at least in this case it must.
Have a look just above <item> and see if that does the trick.
Good luck.

GX700 Crashes when scanning for TV channels!

Hi forum.
I've got a GX700 with TV-tuner. Everything else on the PC is working like a charm, but when scanning for TV-channels in DVBViewer Pro and CyberLink PowerCinema, the PC simply crashes, and a nice blue-screen error message appears. The Scanning always make it to 98 %, without finding a single channel, and then the crash occurs. I'm using Vista 64-bit.

Quote
and a nice blue-screen error message appears.
And says what? >>> Getting help with random restarts and Blue Screens <<<

AI Continuous Scan.vi and channel inputs

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