Connect a analog input in differential connection

iam using three flowmeters and a pressure transducer and they are connected to PCI-MIO-16 E 1 DAQ card. i have connected all three in differential mode. i have connected them as channels 0 to 3.channel 0 AI0(+)AND ai8(-) and AI 8 to AIGND(67) for grounding.in the same way for other flowmeters i have grounded the -ve pin to AIGND.but i get incorrect values . can anyone help me in this issue?

Hello alphones,
Wilfried brought up some good questions to ask. Are your sensors grounded or floating? In either case his descriptions are accurate as to how you will need to connect the sensors to your device. I have linked the connection diagram for the PCI-MIO-16E along with a really great wiring guide. Let me know if you have any additional questions.
E Series User Manual (Appendix B, figure B-1)
Field Wiring and Noise Considerations for Analog Signals (Table 1 has a lot of great information)
Regards,
Chris Behnke
Sr. RF Engineer
High Frequency Measurements

Similar Messages

NI-MyRIO Analog Inputs

Greetings,
I'm just getting the myRIO up and running, and I'm sort of disappointed that the +/- analog inputs are differential only. Is there any low level way to use these channels differently, or at least each as single-ended? Pseudo-differential, perhaps? I'm going to have to resort to using the line-level audio inputs to measure single ended inputs and make sure the input level is lower than whatever the max voltage is for that (1.7 volts or something).
Any users out there care to comment?
I know the other inputs are single ended, but only 0-5V. Bummer.
Thanks in advance.
TR
><><><><><><
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><><><><><><

I grounded the 0- and 1- inputs of the two differential channels and had no problem measuring single ended voltages going into 0+ and 1+. I was just expecting to be able to configure the four inputs to be four single-ended inputs like I normally can do on all other NI DAQ analog hardware. The project I'm working on needs four measurments (all +/- voltages), so I was hoping the two +/- 10 channels were reconfigurable to four, like I'm used to. I'm just going to have to be creative and use the audio inputs as well.
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Connecting OxyGuard Model 420 - Dissolved Oxygen Sensor- to FieldPoint 1601 , FP-AI-110 analog input

Hello,
i have OxyGuard Model 420 (Dissolved Oxygen Sensor 4-20 ma)
that i want to connect to my FieldPoint 1601 , FP-AI-110 analog input.
i'm using LabView 7.1
this sensor have 2 wires, and i dont want to make mistakes and destroy the sensor,
how i connect it ,physically to the FP ?
do i need to connect the sensor to the VC in the FP module ?
if someone can post a sketch of the Circuit i will be more than happy.
thanks in advance.
mor

hello mor
As all 2 wire-current sensors, the Oxyguard Sensor must be connected to the power source = Vsup terminal with the Brown_wire , not to the COM !(channel 0 , number 17 in the FP-AI-110 module)
the Blue_wire u connected OK to Iin (channel 0 , number 2 in the FP-AI-110 module) .
See also in the Connection Example at the end of the link u attached.
We use the same sensor & configuration for a long time in Fishery Control Systems.
I have no explanation wy its look fine in MAX with the old connections .
Hope it help u
Shimon
Try to take over the world!

Failure to read analog inputs

I have a USB6008 with amplified thermocouple signals coming in to the first 4 analog input ports. I have installed DAQmx3.1 on my mac and am trying to use the nidatalogger to read any values from them. Unfortunately I can not seem to read any of the analog ports. In nidatalogger i am given the choice of physical ports 1-7 all of which do not react to analog inputs on the board. They do however react when I apply voltages to some of the digital input pins, most noticable port 30. I am completely confused and since things like MAX dont exsist for the mac, I have no clue how to go about figuring out what is wrong. Help!

Thanks for posting on the NI Forums! I understand you are having trouble reading data from your analog inputs on the USB-6008. I am confused as to what terminals you are using. You mentioned that you are using the first 4 analog input ports.
- Does this mean you are connecting wires into terminals 2, 5, 8 and 11?
- How many thermocouples are you using?
- Is your input configuration single ended or differential?
Please refer to page 13 of the NI USB 6008 User Guide and Specifications, and clarify which terminals you are physically wiring to. You had also mentioned port 30, however if you look on page 14 you can see that terminal 30 corresponds to the +2.5 V pin.
General DAQ Troubleshooting and FAQ under Mac OS
Rod T.

Error 10800 while testing analog input PCI-4451

I'm testing the PCI 4451 device under Windows 2000 and with NI-DAQ 6.9.2 (with Max 2.2 french version)
The analog output work properly but the input doesn't seem to work. I have tested with a GBF. I have also tested by connecting directly the analog output on the analog input and generating a 50KHz signal at 5V but it doesn't work. It always return an error 10800 (timeOutError). I haven't select any trigger. It display a graph with 1 or 2 peak an the beginning but all others samples have the value 0 in the graph. So the graph seems like a constant value of zero exepts the 1 or 2 peak.
I've tried a lot of combinaison and nothing work. :-(
configuration of the NI PCI-4451 :
IRQ : 19
DMA : 0, 1 and 2
AI : +/- 10V
differential
AO : bipolar
Accessory : BNC-2140
PS : I've translated from french so there could have some mistakes.
Is there anyone who have an idea ? (or others tests I can do ?)
pcb

Vous adoptez la bonne demarche - Si la carte ne "repond" pas dans MAX, ce n'est pas la peine d'aller plus loin.
Ce que je vous conseillerais de faire :
1- Aller dans le panneau "proprietes" et choisissez "tester les ressources" - cela vous permettra de savoir si la carte repond aux commandes du driver.
2-Si oui, lancer les panneaux de tests et generer un signal de 1 khz avec un GBF (en gardant la frequence d'echantilloonnage par defaut de 51200S/s)
Si vous obtenez un warning "10800", essayez de fermer le panneau de test (cela va envoyer une commande de "reset" a la carte puis relancer le panneau de test immediatemment apres)
Le seul cas de figure ou j'ai pu rencontre ce comportement etait apres avoir synchronise plusieurs car
tes 4451 - Les lignes des cartes "esclaves" n'ayant pas ete remises a zero apres coup.
Je doute toutefois que vous soyez dans ce cas de figure.
2bis- Si le panneau "tester les ressources" vous renvoie une erreur, cela signifie que la carte ne recoit pas les commandes du driver.
Le plus simple dans ce cas etant probablement d'eteindre votre PC et de placer la carte dans un emplacement PCI different. Au redemarrage, de nouvelles ressources seront affectees a la carte et cela permettra eventuellement d'eliminer les conflits potentiels.
Si aucune de ces deux methodes ne vous apporte un resultat, je crains que vous ne deviez contacter votre agence National Instruments pour proceder a un remplacement de cette carte.
J'espere que ces informations vous seront utiles.
Gerald

Interference of analog inputs

Hi,
I have problem with analog input measurement. I am using NI PCIe-6351 for measuring voltage signal from 3 sensors - accelerometer (differential connection to AI4) and 2 pressure sensors (differential connection to AI0 and AI1). If I measure signal from accelerometer and pressure sensors separately using SignalExpress everything seems working. However if I measure these signals together it looks like they influence each other, concretely analog signal of accelerometer increases value of pressures during dynamical measurement. Measuring only pressures looks all right.
Behaviour of signals is shown in the figure below. Upper two figures show separate measurement of signals AI0 and AI4, bottom figure shows signals measured together/simultaneously (signals are noisy but they should be constant).
Thank you so much for your suggestions.
Jaroslav Bušek
Attachments:
ni.png ‏15 KB

Dear Jaroslav!
If I understand your image correctly, the issue is the oppositve of what you described, so the accelerometer (AI4) is being affected (offset by a fairly constant DC value) by the pressure measurement (AI0). What is your measuring frequency?
There are a few suggestions off the top of my head:
1. Check shielding on your sensors to ensure on crosstalk is happening on the measurement itself.
2. Create a dummy task on AI3, measuring a constant 0 to zero out your ADC in between channels.
3. Depending on your application, you could decrease the sample rate on one, or all sensors.
Hope some of this you'll find useful.
Best regards:
Andrew Valko
NI Hungary
Andrew Valko
National Instruments Hungary

Analog inputs no longer working on Audigy 2 ZS Platinum Pro's external dr

I have an Audigy 2 ZS Platinum Pro. After two years of use without problems, the analog inputs on the external dri've have stopped working. I get no signal from them, not even noise. All 3 inputs are silent, Line in / Mic and Line 2 in the front, and Line 3 in the back. Otherwise the dri've appears to function normally - I get output from the headphone jack, and the volume control knob works. I have not tested digital inputs or outputs, as I currently have no digital devices to connect to them.
I had made no major changes to my computer - software or hardware - when the problems began. I recently added a new SATA hard dri've, but the Audigy dri've did work after that.
I've taken steps suggested in another thread on this forum and uninstalled all Creative software and drivers, used the latest driver package's uninstall program as well as Driver Cleaner, and finally manually deleted everything related to Creative and Audigy from the system registry (and rebooted quite a few times in between). I then installed the original drivers from the CD that came with the sound card (a setup that has worked before), but still the problem persists.
Any ideas on where to even begin looking for a solution? I find it hard to believe that it's a hardware problem, since three inputs suddenly went silent at the same time, and no other connections were affected. Yet I've done as clean a reinstall as possible, and that hasn't solved the problem.
My current computer configuration:
OS: Windows XP Pro (SP2 and all latest updates)
CPU: Athlon XP 500+
RAM: 2x 52 MB
Motherboard: Abit AN7 (integrated sound chip disabled)
Video card: Sapphire Radeon 9800 Pro
Network card: D-Link DFE-530TX
Hard dri've : Seagate ST320026A, 20 GB IDE
Hard dri've 2: Maxtor 6L080J4, 80 GB IDE
Hard dri've 3: Seagate ST330083, 300 GB SATA-II

I don't have a Platinum Pro or the dri've, but a general hardware troubleshooting step I would take would be to remove the soundcard and either move it to another slot or re-seat it. Also, I'd disconnnect and reconnect all cables to and from the card and the dri've. If I had another machine I could try the card or dri've in, I'd do that. If I could borrow another dri've or even another card, I'd test those too. (Swapping parts is often the simplest diagnostic.) Yeah, maybe it's not a hardware problem, but I'd take these steps just to rule out some possibilities.
Edit: And if you can remove or disconnect the SATA dri've and restore the system to the condition before you installed it, that's another good test.Message Edited by Katman on 2-8-2005 2:56 AM

How to synchronize analog input and output from two different USB daq boards

Hi all,
I have two very differnt USB boards the NI USB 6008, which I am using to acquire the data (Analog Input) and a NI USB 9263, it is an Analog Output only board that I am using to deliver a signal (in this case a square pulse). The reason why I am not using the 6008 Analog Ouputs is because I need to deliver negative voltages and need the full +/-10V range.
Looking at similar posts I am pretty sure that I can't use an external trigger or a shared clock, I also tried to use the synchronization of timed structures but no cigar.
I am including a quick vi that I whipped out showing how the signal jitters due to the lack of synchronization. The AO from the 9263 connects to the AI in the 6008 in this example.
Solved!
Go to Solution.
Attachments:
Test Pulse.vi ‏117 KB

I talked to a specialist in the phone and tols me that it is not possible.

The device PCI 6036E: Analog Input error:"the device is not responding to the base address",Output :No signal

I am using PCI 6036E DAQ card, DAQ 6.9.2. , I have not connected to any external device.
When I tested card(in Test Panel of MAX2.2,DAQ 6.9.2) an error appearing �the device is not responding to the base address� � then I pressed Yes, Then TestPanel window appearing�
In analog Input Tag, there is an error �-10805�. This error also appearing when I run the standard analog input samples (use Delphi 6.0).
I tested analog output functions in TestPanel, Delphi Examples, LabView 6.1. There are not error appearing but there is not output signal (using Oscilloscope to see).
Output, Input digital functions are working correctly.
Next I try to foll
ow all the instruntions as recommended:
-Changing TO another slots PCI
-Reinstall Os WinXP,98SE�
-Use another Computer�
But all of the cases are still not working.(the above error still appeared, no output signal)

Nvd,
I'm sorry to hear about the problems that you are running into with your DAQCard. I can understand your frustration with the errors that you are seeing. You mention that you have tried to do some troubleshooting, I was wondering if you have tried all the troubleshooting techniques listed in this KnowledgeBase:
http://digital.ni.com/public.nsf/websearch/DCFCDB240788F8D486256D6A00834D80?OpenDocument
If you have tried all of those things, I would suggest one additional thing to try. I would suggest updating your NI-DAQ drivers to version 7.0. These drivers are the newest versions of our Data Acquisition Drivers, and can be downloaded from our website here:
http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C128D?OpenDocument&
node=132060_US
If you have tried all of the above troubleshooting options, please post a detailed description of what you have tried. This may help to clarify what is going wrong.
Jed R.
Applications Engineer
National Instruments

7831R Analog Input Noise Problems

Hi,
I am running a data logging application which samples the analog inputs of my 7831R FPGA card with a sample rate of 10KHz. I am interested in how noisy the PXI system itself is, so I shorten AI0+ and AI0- together, hook both of them up to A0GND through a 10K resistor (all done in the SCB-68 breakout box which is connected to the FPGA card through a SH68-C68-S cable) and log data from the analog input.
The data log shows about 12 counts of noise in the system. That's about 3.5 bit. Is there any way I can reduce the noise?
Thanks,
Chris

Hi Pete,
You are right in saying that the 7831R boards should acquire data much faster than 10KHz. Infact you can take a look at the actual specs from the data sheet http://sine.ni.com/nips/cds/view/p/lang/en/nid/14757 as well as the product manual. However, I am concerned that you may be measuring the rate of acquisition on the RT VI (or any host vi) you are running as opposed measuring it in the FPGA VI.
Your time critical loop may be running at 228 ticks of the 40 MHz clock but the data is buffered (at that rate) and has to be then transferred to the communication loop which then sends the data to the host vi (which may be your RT vi). Hence, the rate at which host VI receives the data will be much slower than the FPGA VI is acquiring data.
Hope this helps!
Prashanth

Can the analog inputs be daisy chained to measure higher voltages?

Can the analog inputs of a PXI-6289 be connected in series to measure higher voltages than normally allowed at the analog inputs of the PXI-6289 (i.e. 10 VDC)? For example, let's say I wanted to measure 18 VDC using an analog input channel of the PXI-6289. I would then pick two AI channels and connect the positive of one to the negative of the other and then the two remaining leads would be placed across the 18 VDC. Resistors could also be placed across the 18 VDC to form a votage divide. One AI would measure the voltage across one resistor and the other AI would measure the voltage across the remaining resistor. I have tried this and the voltage measurements appear to loose accuracy. Thank you for your help.

Hello Rafi,
You may want to invest in a high voltage attenuator for signal conditioning prior to reading the signal. The documents below may also be helpful:
High Voltage and Isolated Measurements
http://zone.ni.com/devzone/cda/tut/p/id/10693
High-Voltage Measurements and Isolation
http://zone.ni.com/devzone/cda/tut/p/id/3410
Regards,
Roman Sandoval | National Instruments | RF Systems Engineer

Please help with C code to synchronize counter output to analog input

Hi All,
I am using NI DAQ USB-6353 with text-based C code to control it. I would like to send a continuous pulse train from the DAQ to pulse a power supply, which then activates an electron beam producing current to be read by the analog input port of the same DAQ. I would like to keep only the analog samples during the pulse peak and samples of a couple pulse widths right after. I am successfully to generate a pulse train using the sampled clock from a counter output channel, but fail to use the same clock to synchronize the pulse train with the analog input. DAQmxReadAnalogF64 is not called by the static function EveryNCallback set for the analog input task. Am I doing something wrong with the following codes? It would be great if it turns out only I am using the wrong sampled clock name of the counter ("dev1/PFI8") for the analog input. Or is something more fundamental that a counter cannot be sync. with an analog input?
Would someone be able to send me a link to an example in C or C++ or visual basic showing how to synchronize a buffered sample clocked digital pulse train from a counter output channel to an analog input? To simplify the post, the below codes do not include the static functions EveryNCallback and DoneCallBack, but I can send them if needed.
Many thanks in advance for your help,
Thuc Bui
//setting operation parameters
double initDelay = 0.0, freq = 10;
double dutyCycle = 0.0001;           //thus pulse width is 10 microsec
unsigned highTicks = 4;   //per period
unsigned numSamplesPerPeriod = highTicks / dutyCycle; //40000 samples/period
unsigned lowTicks = numSamplesPerPeriod - highTicks;      //per period
unsigned sampleRate = 2*numSamplesPerPeriod*freq;       //800000 samples/s
//create counter
TaskHandle counterTask;
int errCode = DAQmxCreateTask("", & counterTask);
errCode = DAQmxCreateCOPulseChanFreq(counterTask, "dev1/ctr0", "",
                                 DAQmx_Val_Hz, DAQmx_Val_Low,
                                 initDelay, freq, dutyCycle);
errCode = DAQmxCfgSampClkTiming(counterTask, "dev1/PFI8", sampleRate, DAQmx_Val_Rising,
                           DAQmx_Val_ContSamp, numSamplesPerPeriod);
//create analog input
TaskHandle aiTask;
double minVolt = 0.0, maxVolt = 1.0;
errCode = DAQmxCreateAIVoltageChan(aiTask, "dev1/ai0", "", DAQmx_Val_Diff,
                                 minVolt, maxVolt, DAQmx_Val_Volts, "");
unsigned bufferSize = 10* numSamplesPerPeriod;
errCode = DAQmxSetBufInputBufSize(aiTask, bufferSize);
errCode = DAQmxCfgSampClkTiming(aiTask, "dev1/PFI8", sampleRate, DAQmx_Val_Rising, DAQmx_Val_ContSamp, numSamplesPerPeriod);
errCode = DAQmxRegisterEveryNSamplesEvent(aiTask, DAQmx_Val_Acquired_Into_Buffer,
                                        numSamplesPerPeriod, 0, EveryNCallback, 0);
errCode = DAQmxRegisterDoneEvent(aiTask, 0, DoneCallBack, 0)
//start aiTask first
errCode = DAQmxStartTask(aiTask);
//then counterTask
errCode = DAQmxStartTask(counterTask);

Hi Xavier,
Thank you very much for getting back to me. I really appreciate it. I followed your advice with the option 2 and simplified my code by using one of the NI C example templates to generate the below codes (also attached). I was able to see the pulses generated with an oscilloscope, and on the same oscilloscope I could see the ouput pulses of the electron beam probe. Unfortunately, the below code via DAQmxReadAnalogF64 reports of no data read from the probe and finally times out. Below is the error message given by this function. I did check the connection of the analog input wires to make sure they were connected to pin 1 (A0+) and 2 (A0-) because I was using the terminal configuration DAQmx_Val_Diff. Do you see any obvious errors I have made in my codes?
Thanks a lot for your help,
Thuc Bui
Task started, waiting for trigger...
Acquired 0 analog samples DAQmx Error: Some or all of the samples requested have not yet been acquired.
To wait for the samples to become available use a longer read timeout or read later in your program. To make the samples available sooner, increase the sample rate. If your task uses a start trigger, make sure that your start trigger is configured correctly. It is also possible that you configured the task for external timing, and no clock was supplied. If this is the case, supply an external clock.
Property: DAQmx_Read_RelativeTo
Corresponding Value: DAQmx_Val_CurrReadPos
Property: DAQmx_Read_Offset
Corresponding Value: 0
Task Name: _unnamedTask<1>
Status Code: -200284
End of program, press Enter key to quit
********************** C Code **************************************************
#include <stdio.h>
#include "NIDAQmx.h"
#include <math.h>
#define DAQmxErrChk(functionCall) { if( DAQmxFailed(error=(functionCall)) ) { goto Error; } }
int main(void) {
int32 error = 0;
char errBuff[2048]={'\0'};
TaskHandle taskHandleDig=0;
TaskHandle taskHandleAna=0;
double  timeout=10;
double minVol = -1.0, maxVol = 1.0;
double initDelay = 0.0;
double freq = 10.0;
double pulseWidth = 1.0e-5; //10us
double dutyCycle = pulseWidth * freq;
unsigned hiTicks = 4;
double sampleRate = hiTicks/pulseWidth; //samples/s
unsigned lowTicks = ceil(sampleRate/freq) - hiTicks;
unsigned nSpPeriod = hiTicks + lowTicks;
unsigned numPulses = 1;
unsigned nSpCh = numPulses*nSpPeriod;
double sampleRate2 = ceil(2.0*sampleRate);
unsigned sampleMode = DAQmx_Val_FiniteSamps;
/*********************************************/ /*/ DAQmx Configure Code /*********************************************/
DAQmxErrChk(DAQmxCreateTask("", &taskHandleDig)); DAQmxErrChk(DAQmxCreateTask("", &taskHandleAna));
DAQmxErrChk(DAQmxCreateAIVoltageChan(taskHandleAna, "Dev2/ai0", "", DAQmx_Val_Diff, minVol, maxVol, DAQmx_Val_Volts, ""));
DAQmxErrChk(DAQmxCfgSampClkTiming(taskHandleAna, "/Dev2/Ctr0InternalOutput", sampleRate2, DAQmx_Val_Rising, sampleMode, nSpCh));
DAQmxErrChk(DAQmxCreateCOPulseChanFreq(taskHandleDig, "Dev2/ctr0", "", DAQmx_Val_Hz, DAQmx_Val_Low, initDelay, freq, dutyCycle));
DAQmxErrChk(DAQmxCfgSampClkTiming(taskHandleDig, "/Dev2/PFI12", sampleRate2, DAQmx_Val_Rising, sampleMode, nSpCh));
unsigned bufferSize = nSpCh;
DAQmxErrChk(DAQmxSetBufInputBufSize(taskHandleAna, bufferSize));
DAQmxErrChk(DAQmxSetBufOutputBufSize(taskHandleDig, bufferSize));
/*********************************************/ /*/ DAQmx Write Code /*********************************************/
DAQmxErrChk(DAQmxWriteCtrTicksScalar(taskHandleDig, 0, timeout, hiTicks, lowTicks, NULL));
/*********************************************/ /*/ DAQmx Start Code /*********************************************/
DAQmxErrChk(DAQmxStartTask(taskHandleAna)); DAQmxErrChk(DAQmxStartTask(taskHandleDig));
printf("Task started, waiting for trigger...\n");
/*********************************************/ /*/ DAQmx Read Code /*********************************************/
double* dataAna = new double[nSpCh];
int32 numReadAna = 0;
int errCode = DAQmxReadAnalogF64(taskHandleAna, -1, timeout, DAQmx_Val_GroupByChannel, dataAna, nSpCh, &numReadAna, NULL);
printf("Acquired %d analog samples\n",numReadAna);
if (numReadAna) {
    unsigned nPts = (numReadAna < hiTicks)? numReadAna : hiTicks;
   for (unsigned n = 0; n < nPts; ++n) {
         printf("%6.3f ", dataAna[n]);
    printf("\n");
delete [] dataAna;
DAQmxErrChk(errCode);
Error:
if( DAQmxFailed(error) )   DAQmxGetExtendedErrorInfo(errBuff,2048);
if( taskHandleDig!=0 && taskHandleAna!=0 ) {
/*********************************************/   /*/ DAQmx Stop Code   /*********************************************/
    DAQmxStopTask(taskHandleDig);
    DAQmxClearTask(taskHandleDig);
    DAQmxStopTask(taskHandleAna);
    DAQmxClearTask(taskHandleAna);
if( DAQmxFailed(error) )   printf("DAQmx Error: %s\n",errBuff);
printf("End of program, press Enter key to quit\n");
getchar();
return 0;
Attachments:
Correlated DIO AI_Sample_Clock Dig Start.c ‏6 KB

6025e Analog Input not shown correctly

I use a 6025e on the Analog input channel 0 are 7 volt connected. The Testpanel show this Voltage but if i read this channel via AI_VRead(DAQ_Devicenumber,DAQ_force,1,&force)
i receive only 4.99 Voltage.
why ?
what should i do, to solve the problem

SuperWolfi,
If you look at the 6025E User Manual, in the Specifications Appendix A, you will see that for a gain setting of 1 you will have an input range of +/-5V. If you use a gain setting of 0.5 then your input range is expanded to +/- 10V.
In your call to AI_VRead you are using a gain of 1, instead of 0.5. For information on how to set the gain for your board, please reference Appendix B:
Analog Input Channel, Gain Settings, and Voltage Calculation of the NI-DAQ Function Reference Manual. You will find that -1 translates to a gain of 0.5.
6023E/6024E/6025E User Manual
http://digital.ni.com/manuals.nsf/websearch/0C88F40FFE7F28CD862569AE00574AC1?OpenDocument&node=1065_US
NI-DAQ Function Reference Manual for PC Compatibles
http://digi
tal.ni.com/manuals.nsf/websearch/1630A0B68738B269862567C1007A2912?OpenDocument&node=132100_US
Regards,
Justin Britten
Applications Engineer
National Instruments

Newbie, Would like to use analog input and graph

I was using the "Real Time Chart.vi" example in Labview 2011 and got it all set up using the random input it comes with. I have a USB-6008 that is set up and I can see the signal in MAX. The big question is how the heck do I get the vi to work with the analog input? If someone could modify the vi and add the AI0 as the input I would really appricate it!!
Thanks
Attachments:
Soil Moisture.vi ‏15 KB

trimixdiver1 wrote:
Aside from me adding the gage and bar graph, its the same as the example. Ive added the AI (purple) channel but I guess I need to add some Daqmx stuff to allow it to connect to the strip chart.
Wheres the analog in channel? Is this something you haven't posted yet? Make your changes, then post when you are ready.
Reese, (former CLAD, future CLD)
Some people call me the Space Cowboy!
Some call me the gangster of love.
Some people call me MoReese!
...I'm right here baby, right here, right here, right here at home

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

Connect a analog input in differential connection

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