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By paulofelora
I have a requirement that I thought would be SIMPLE, but can't get it to work. I have a 9205 card in a little 9174 cDAQ USB chassis.
My *intended* behavior is to wait (block) at the DAQmx Trigger/Start Analog Edge on, say channel ai1, until I get a falling edge thru, say, -0.050V. So I have a little vi (that contains 2 parallel loops) that I want to sit & wait for the trigger to be satisifed. I'm doing "routine" voltage measurements in another AI loop on a different channel. I want this vi to run separately from my "routine" voltage measurements because I want the app to respond "instantly" to input voltage exceeding a limit to prevent expensive damage to load cells. I was afraid that if I used either Finite or Continuous sampling to "catch" an excessive voltage, I might miss it while I'm doing something else. Yes, yes, a cRIO real-time setup would be better for this, but this is a very cost-sensitive task... I just want to "Arm & Forget" this process until it gets triggered, whereupon it fires an event at me. SO... I'm also reading the same voltage on channel ai0 for regular-ole voltage measurements, and just jumpering them together. I did this because I read somewhere that you can't use the same channel for multiple DAQ tasks - I *thought* I would need to set up the tasks differently. {but now that think about it, the setups can be the same...}.
I've set up the DAQmx task the same as shipping examples and lots of posts I've seen. I'm supplying a nice clean DC voltage to a 9205 card using a high quality HP variable power supply. Using NI-MAX, I've verified that my 9174 chassis & 9205 are working properly.
THE PROBLEM - When I run it, the vi just sails right through to the end, with no error, and an empty data array out. No matter WHAT crazy voltage I give the "DAQmx Trigger.vi" (set up for Start Analog Edge), it never waits for the trigger to be satisfied, just breezes on through as if it weren't there. If I set the Sample Clock for "Finite Samples", the DAQmx Read fails with timeout - makes sense, since the trigger wasn't satisfied. What could I possibly be doing wrong with such a simple task???????
So my fundamental misunderstanding still vexes me - does the DAQmx Trigger vi not block and wait for the trigger condition to be satisfied, like the instructions state - "Configures the task to start acquiring or generating samples when an analog signal crosses the level you specify"?
I stripped my requirement down to the bare essentials - see the 1st snippet, the 2nd is my actual vi. Any ideas, anybody?
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By Benoit
This XML test report library is available for you to modify at your will.
It is based on the IPC-2547 standard so it is easier for any other application or database to parse.
The html file report offered by LabVIEW was not sufficient for my need.
So I created those. enjoy!!!
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By Benoit
View File .xml test report Measurements.zip
This XML test report library is available for you to modify at your will.
It is based on the IPC-2547 standard so it is easier for any other application or database to parse.
The html file report offered by LabVIEW was not sufficient for my need.
So I created those. enjoy!!!
Submitter Benoit Submitted 02/26/2018 Category *Uncertified* LabVIEW Version
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By neunited
Dear All,
I'm new to this forum and I'm really glad I became a member.
I am currently in the phase of designing a simple program which can control all the DAQmx channels using a configuration file (.ini) which is capable of change voltage range during mid-simulation.
At the moment my .ini file reads as follows:
[AO Channel 1]
Name = T2
Physical Channel = cDAQ1Mod1/ao0
Max Value = 10
Min Value = 0
[AO Channel 2]
Name = T3
Physical Channel = cDAQ1Mod1/ao1
Max Value = 10
Min Value = 0
[AO Channel 1]
Name = T2
Physical Channel = cDAQ1Mod1/ao0
Max Value = 5
Min Value = 0
[AO Channel 2]
Name = T3
Physical Channel = cDAQ1Mod1/ao1
Max Value = 10
Min Value = 0
My LabVIEW VI for the .ini script is attached. I'm relatively new to using configuration file functions and I don't really understand where "Get Key Names" section should be wired to. I have placed a constant on it for now which reads the "AO Channel 1" but how can I get it to read all the channels in the .ini file.
I am welcome to all suggestions here, I just want to make sure that I don't cause any problems to any of the channels and use best practice methods. All constructive criticism welcome!
Thank you.
Read Configuration (INI) File (1).vi
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By Mafis
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<DCT Version="V3.0" User="Administrator" FileType="4" TagListFile=""><DATASOURCE Name="Marchwood" User="root" Password="" Driver="PI"/><PLANT PlantName="Marchwood" UnitName="Plant" ConfigFile="MAR1_Avg_000.XML" ConfigFileCreation="16/04/2007 14:01:40" TimeBias="0" Locale="(GMT) Greenwich Mean Time : Dublin, Edinburgh, Lisbon, London"/><DATA_MESSAGE Type="Average" TimeBegin="31-Dec-2007 00:00:00" TimeEnd="01-Jan-2008 00:00:00" SamplePeriod="00:05:00" RequestType="Automatic" TransferPeriod="24"><DATA_POINT PopName="11GB_VIB_HP-SMAX" TagName="11GB_VIB_HP-SMAX" Vartype="A" UnitLabel="µm"><SAMPLE TimeStamp="1199059500" Validity="0" Value="1.274646E+01"/><SAMPLE TimeStamp="1199059800" Validity="0" Value="1.260714E+01"/><SAMPLE TimeStamp="1199060100" Validity="0" Value="1.248902E+01"/><SAMPLE TimeStamp="1199060400" Validity="0" Value="1.236600E+01"/><SAMPLE TimeStamp="1199060700" Validity="0" Value="1.231612E+01"/><SAMPLE TimeStamp="1199061000" Validity="0" Value="1.237882E+01"/><SAMPLE TimeStamp="1199061300" Validity="0" Value="1.231513E+01"/><SAMPLE TimeStamp="1199061600" Validity="0" Value="1.233609E+01"/><SAMPLE TimeStamp="1199061900" Validity="0" Value="1.235653E+01"/><SAMPLE TimeStamp="1199062200" Validity="0" Value="1.236966E+01"/><SAMPLE TimeStamp="1199062500" Validity="0" Value="1.235595E+01"/><SAMPLE TimeStamp="1199062800" Validity="0" Value="1.221824E+01"/><SAMPLE TimeStamp="1199063100" Validity="0" Value="1.210020E+01"/><SAMPLE TimeStamp="1199063400" Validity="0" Value="1.202238E+01"/><SAMPLE TimeStamp="1199063700" Validity="0" Value="1.220617E+01"/><SAMPLE TimeStamp="1199064000" Validity="0" Value="1.231157E+01"/><SAMPLE TimeStamp="1199064300" Validity="0" Value="1.228374E+01"/><SAMPLE TimeStamp="1199064600" Validity="0" Value="1.230319E+01"/><SAMPLE TimeStamp="1199064900" Validity="0" Value="1.237157E+01"/><SAMPLE TimeStamp="1199065200" Validity="0" Value="1.231859E+01"/><SAMPLE TimeStamp="1199065500" Validity="0" Value="1.228248E+01"/><SAMPLE TimeStamp="1199065800" Validity="0" Value="1.235305E+01"/><SAMPLE TimeStamp="1199066100" Validity="0" Value="1.248533E+01"/><SAMPLE TimeStamp="1199066400" Validity="0" Value="1.242054E+01"/><SAMPLE TimeStamp="1199066700" Validity="0" Value="1.230065E+01"/><SAMPLE TimeStamp="1199067000" Validity="0" Value="1.228046E+01"/><SAMPLE TimeStamp="1199067300" Validity="0" Value="1.245642E+01"/><SAMPLE TimeStamp="1199067600" Validity="0" Value="1.245089E+01"/><SAMPLE TimeStamp="1199067900" Validity="0" Value="1.239629E+01"/><SAMPLE TimeStamp="1199068200" Validity="0" Value="1.242647E+01"/><SAMPLE TimeStamp="1199068500" Validity="0" Value="1.249479E+01"/><SAMPLE TimeStamp="1199068800" Validity="0" Value="1.251456E+01"/><SAMPLE TimeStamp="1199069100" Validity="0" Value="1.266746E+01"/><SAMPLE TimeStamp="1199069400" Validity="0" Value="1.266234E+01"/><SAMPLE TimeStamp="1199069700" Validity="0" Value="1.266106E+01"/><SAMPLE TimeStamp="1199070000" Validity="0" Value="1.259365E+01"/><SAMPLE TimeStamp="1199070300" Validity="0" Value="1.238166E+01"/><SAMPLE TimeStamp="1199070600" Validity="0" Value="1.229414E+01"/><SAMPLE TimeStamp="1199070900" Validity="0" Value="1.224306E+01"/><SAMPLE TimeStamp="1199071200" Validity="0" Value="1.225017E+01"/><SAMPLE TimeStamp="1199071500" Validity="0" Value="1.207360E+01"/><SAMPLE TimeStamp="1199071800" Validity="0" Value="1.223199E+01"/><SAMPLE TimeStamp="1199072100" Validity="0" Value="1.232578E+01"/><SAMPLE TimeStamp="1199072400" Validity="0" Value="1.236228E+01"/><SAMPLE TimeStamp="1199072700" Validity="0" Value="1.243583E+01"/><SAMPLE TimeStamp="1199073000" Validity="0" Value="1.254738E+01"/><SAMPLE TimeStamp="1199073300" Validity="0" Value="1.279570E+01"/><SAMPLE TimeStamp="1199073600" Validity="0" Value="1.317496E+01"/><SAMPLE TimeStamp="1199073900" Validity="0" Value="1.322220E+01"/><SAMPLE TimeStamp="1199074200" Validity="0" Value="1.337082E+01"/><SAMPLE TimeStamp="1199074500" Validity="0" Value="1.323367E+01"/><SAMPLE TimeStamp="1199074800" Validity="0" Value="1.274038E+01"/><SAMPLE TimeStamp="1199075100" Validity="0" Value="1.235951E+01"/><SAMPLE TimeStamp="1199075400" Validity="0" Value="1.243144E+01"/><SAMPLE TimeStamp="1199075700" Validity="0" Value="1.255276E+01"/><SAMPLE TimeStamp="1199076000" Validity="0" Value="1.263342E+01"/><SAMPLE TimeStamp="1199076300" Validity="0" Value="1.252355E+01"/><SAMPLE TimeStamp="1199076600" Validity="0" Value="1.254722E+01"/><SAMPLE TimeStamp="1199076900" Validity="0" Value="1.261100E+01"/><SAMPLE TimeStamp="1199077200" Validity="0" Value="1.265973E+01"/><SAMPLE TimeStamp="1199077500" Validity="0" Value="1.257116E+01"/><SAMPLE TimeStamp="1199077800" Validity="0" Value="1.245824E+01"/><SAMPLE TimeStamp="1199078100" Validity="0"
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