Analog Input (AI 112) con Filed point

Salve,
non riesco ad acquisire per mezzo del modulo di input AI 112 un segnale prodotto da un generatore di funzioni. I valori letti dal filed point sono diversi da quelli che mi aspetto. Se fornisco una sinusoide a 1Hz con ampiezza picco-picco 2 Volt, acquisisco un segnale tipo onda quadra ma con valori di ampiezza diversi (più piccoli). Dove sbaglio?
Raffaele P.
Research and Development Engineer

Salve,
Grazie per il post. Hai verificato il problema usando Measurement and Automation Explorer (MAX) o LabVIEW? Hai modo di allegare una schermata di questo comportamento? Vorrei anche raccomandarti di utilizzare un DMM esterno per verificare se il segnale di ingresso è effettivamente di 2 Vpp.
Spero questi consigli possano aiutarti.
Jordan Randall
National Instruments Italy

Similar Messages

Can you have set points for analog inputs

if you install an analog input can you get set points that trigger either an alarm or a motor to turn on or off
Solved!
Go to Solution.

In SignalExpress you can use alarms for triggering logging on and off:
Alarms Page - LabVIEW SignalExpress Help
As for turning motors on and off, SignalExpress is not meant for control applications. For controls, you should use LabVIEW either entirely or use a LabVIEW VI from SignalExpress. To do the latter, you could use a LabVIEW VI step in SignalExpress that will execute a LabVIEW VI that does the control processing and outputting that you want. That way you could work in the SignalExpress environment for all the data acquisition, and you would only have to use LabVIEW to program the control VI (or VIs).
Mark E.
National Instruments
Schedule a Free 1-Hour online LabVIEW Tutorial with an NI Applications Engineer

Usb 6009 multiple analog inputs

I am currently attempting to sample two different analog inputs at different sampling rates using a USB 6009. I keep getting the 'resource reserved' error and am wondering if this is not possible using this DAQ. Questions:
1. Does creating two analog input channels on the device cause this error?
2. Is it possible to sample at different rates on channels created in the same task? (i am trying to 'slow down' the second analog input to display switch points to a customer)
3. Running multiple analog inputs using independent timing would be better achieved by switching to a higher end DAQ? If so which would you recommend?
I have attached my vi. Thank you in advance for your help.
I surf therefore I am....
Attachments:
demo_nolvl.vi ‏27 KB

The DAQ boards only have 1 timing clock for the analog inputs/outputs. So you can only have 1 sample rate on a given card. I would recommend just sampling at the highest of the desired rates in a single task.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
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Synchronizing two counter frequency inputs with multiple analog inputs

Hello all,
I'm fairly new to LabVIEW and I'm trying to collect data from multiple sources with synchronized timing on the acquisition but I'm having trouble figuring it out. My problem is that I've got two counter frequency inputs, one optical tachometer reading one pulse per revolution, and a max machinery flow meter with a k factor of 12000. I can't seem to figure out how to sync the timing with my multiple analog inputs. I've been attempting to get the tachometer to sync with the analog inputs first by following the example linked here. (https://decibel.ni.com/content/docs/DOC-10785) So far each time I run it I either get a timeout error on the DAQmx read or a "Multiple sample clock pulses were detected" error (see attached image). It seems if I slow the sampling rate way down to say 10 hz and ensure that the tachometer signal is over 800-1000 RPM (13-17 Hz) before starting the VI then the program will run without errors until the RPM drops below that threshold then the "Multiple sample clock pulses" error occurs. The code is attached below.
Does anyone know of a more effective way of syncing counter frequency inputs with analog inputs? I'd like to have a VI that can show 0 RPM (and eventually 0 flow as well, but I think I need to figure out the timing of one counter before I add another as it seems I can't have two counters in the same task). Any help on this would be greatly appreciated.
LabVIEW version 13.0
cDAQ-9178 Chassis with NI 9401 for the two counter inputs and NI 9205 for the analog inputs.
Thanks!
Richard
Solved!
Go to Solution.
Attachments:
SimpleDAQ.vi ‏44 KB
LV_Error.JPG ‏31 KB

Maybe third times the charm?
So I've finally got a good handle on why the VI is having problems at low RPM though I'm somewhat embarassed how long it took me to do that
Because I have the counter time synced to my Analog input task if it doesn't see at least two pulses between the two clock pulses set by the analog input task I get the -201314 "Multiple sample clock pulses" error. This seems fine at first as it just sets a minimum RPM that I can measure and it's well below the area I'm interested in so no problems there. I tried a simple error handler that would clear the error when it happend assuming the loop would keep iterating until the RPM went above that minimum at which point I would get a signal again. This is not the case, the read function just continues to spit out the -201314 error even after the RPM is back in the readable range. So then I tried adding two case structures so that when the error occured it would stop the task, clear the error, and then start the task again on the next loop iteration (Code Attached). This also doesn't work as the error shows up again on the stop task and then AGAIN on the start task on the next loop iteration. It seems this error is not actually being cleared and once it happens it stays with the task regardless of what the error cluster is carrying.
Anyone have any ideas? The only solution I can think of is to just clear all tasks and recreate them each loop iteration until the RPM is readable again but that strikes me as a horribly clunky solution.
Richard
Attachments:
SimpleDAQ_1_Start Stop.vi ‏48 KB

Analog Input and Output in One Single VI

I need help in setting both analog input and output in one single VI. How do I assign channels to be either input or output? How do I simultaneously uses both in one single VI with a while loop structure?? Which AO am I suppose to use to obtain signal from the function generator I have built to feed into the DAQCard-1200?? Help!!
Attachments:
Test1.vi ‏48 KB

One thing you'll need to be aware of is that you will need to DMA lines: one for AI and one for AO. If you don't, then you can configure the DAQCard to do without DMA using the Config VI. But you certainly can do this.
As far as your function generator, you will want to do a buffered analog output. You will write your buffer of points to the buffer, and then tell NI-DAQ how fast to update your analog output channel with these values.
So, you can be reading from AI and checking the AO process in the same while loop. Just make sure you handle the while loop execution (the wait it exits) correctly. This can get tricky when you're doing two types of measurements.
J.R. Allen

How to use Digital output to turn on sensor for Analog Input?

I am trying to use a digital output to turn on an array of sensors that I then wish to read on 16 analog input lines. I have a 6024E DAQ card. I am planning to take data at 10-20 hz, so not terribly fast, but I will be acquiring for long periods of time (days) so I will be streaming data to disk.
I have a fair bit of experience in Labview basics, but can quickly get out of my depth when I try something new (like this). I have V6.01.
It looks as though the best way might be to do the DO and then a single AI as individual events, then write to disk and continue through the loop. I am puzzled, however, how to keep this cycle on schedule given that I don't know how long it will take to sample 16 channels
, write the data to disk and get back to the starting point... perhaps this is so fast that I don't need to worry about it? The actual timing of the samples (be it 10 or 20 hz) isn't too critical, as long as I can record at what time they were taken... it would be frustrating to find that I was several seconds off after days of data.

Hello,
Thank you for contacting National Instruments.
If you are worried about the time of your acquisition being off, then you should associate each voltage measurement with a timestamp. This will allow you to know the exact time at which the sample was taken and you will never be off. You can use the Get Date/Time in Seconds.vi in our while loop with your AI code so that you can read a sample and read the time. You can than log the voltage value and the timestamp to your file.
Regards,
Bill B
Applications Engineer
National Instruments

Can I read more than 2 analog inputs from myDAQ?

Hello,
I am trying to read 3 voltage values. However, the myDAQ only has 2 analog inputs.
There are multi-meter ports in the myDAQ as well. Could I read the 3rd value via this port?
How would I read these values via the DAQ assit on labVIEW?
Thanks in advance.
Yzhi

Hello Yzhi,
You can acquire from the DMM and the analog inputs using two parallel tasks. The simplest way is to configure one DAQ Assistant for the AI channels, and another DAQ Assistant for the DMM channel. Be aware that the DMM is a software-timed single-point measurement (no hardware waveform acquisition), so you can't tightly synchronize the DMM with the Analog Inputs.
Here is a screenshot demonstrating how to acquire from all three channels. You could also run the DMM in a separate loop so it doesn't slow down AI.
Good luck and let us know if you have any other questions.
Charles Y.
National Instruments
Attachments:
myDAQ acquire two AI and DMM.jpg ‏196 KB

PXI-6230 analog input trigger setup

Hi,
Can anyone point me in the right direction of how to configure the PXI-6230 card to implement 3 of the analog input channels as a digital input trigger? The input to each channel is TTL pulses. I want to have a trigger event on every pulse from any of the three inputs. I'm using LabVIEW 8.5. Any help is appreciated. Thanks.

Hey HarveryL,
I'm not sure it is possible to do this. Can you give me some more details on your application, and why you want to use the analog inputs as a digital trigger? Here is an article on how to use PXI triggers with the analog input and output, perhaps you can adapt that code to your purposes. I'll continue to look into this for you, but any more information you can provide would be appreciated. Have a great week!
John B.
Embedded Networks R&D
National Instruments
Certified LabVIEW Developer

I'm not able to set Analog Input voltages, etc

ok,
so i have an NI DAQ I/O card (NI PCI 6723, or something to that effect) and i'm trying to configure the channels for Analog Input signals.
when i try to choose any kind of setting for Anolog signal by:
>>drop DAQ Assistant vi onto the block diagram
>>>>choose Analog Input
>>>>>>>Voltage
i get this message "No supported devices found"
i thought since I have the I/O card, i should be able to configure channels for both input/output.
i also have ADAC card (from IOTECH) installed but when i look at MAX, i only see the DAQ card.
i'm really confused at this point. can anyone break things down for me ... what i'm doing wrong?
-r

stuartG,
you were right. so what i'm using for the input is a ADAC 5501MF from IOTECH
following their manual (http://www.iotech.com/productmanuals/adac_lvi.pdf) it says that the ADAC-LVi libraries can be located at "Functions->User Libraries" palette of labview.
does this mean that i have to install the ADAC-LVi driver in LabView->User Libraries directory?
if that's not the case then i don't see why the ADAC-LVi is not showing up in the LabView User Libraries since i've installed the driver correctly (in C\Program File\ADAC )
do you have any idea why?
thanks
-r

Programming Analog Input Registers for MSeries NI-6221

I am trying to understand the Preliminary M Series Register Map in order to correctly setup and acquire data from the Analog Input channels of my PCX-6221 card. I have been able to figure out the DIO locations and use them but I am having trouble understanding what I have to do to configure and acquire data using the Analog Input registers of the card. I need to program at this level for an RTX application using Microsoft Visual Studio Net 2003 and have had great success doing so with other NI Cards. I have tried looking at the examples provided by the MDDK but I haven't been able to create a environment that allows me to compile them with Chipobjects and it appears like alot of the work is hidden by the subroutines.
I wonder if someone had a high level algorithum using the Register Map it would help out alot.
Questions:
How would I create a multiple channel Scan List and load it into the card setting gain etc...
How would I configure the card to acquire continously at a specified freq (ex 1000 samples a sec)
How would I start/stop acquisition
I would guess getting the status of the FIFO and accessing the FIFO is a matter of reading the AI_STATUS_1 and AI_FIFO_DATA locations
Would looking at the Register Programming Manual for the "E" Series help me or just get me more confused?
Thanks in advance for any light you can shed on the subject.
Floyd

Hi Floyd-
Let me address your questions individually:
How would I create a multiple channel Scan List and load it into the card setting gain etc...
A multi-channel scanlist can be created as shown in the method aiConfigureChannel() from ai.cpp in the M Series MHDDK \Examples folder. Note that the other operations leading up that point (notably, aiClearConfigurationMemory() must be performed in the order shown in the various AI examples. aiex3.cpp is the most useful starting point for investigation, in my opinion.
How would I configure the card to acquire continously at a specified freq (ex 1000 samples a sec)
aiex3.cpp shows how to setup the device and its DMA controller (aka the "MITE") for DMA operation. In order to configure for continuous operation you set the "continous" flag in that example to kTrue. The effect of that setting is to program the STC-II to generate either a finite or continuous AI sample clock. This programming is performed in the function aiNumberOfSamples() from ai.cpp and has the effect of setting the appropriate bitfield for continuous operation in the AI_Mode_1 register.
Earlier in your post you asked if the STC Technical Reference Manual ( http://digital.ni.com/manuals.nsf/websearch/E929838D7D0EE50986256728007FEADF ) would be a good reference. In fact, it's a great reference from the perspective of understanding the bitfield/register names and understanding the basics of how the timing hardware works (for example BC, UC and other sample counters are all functionally equivalent in the STC and STC-II). From the perspective of actual register writes and reads, the functionality is different between E Series and M Series. The biggest difference, as another forum user alluded, is that we map and write directly to the registers on M Series so Windowed_Mode reads and writes are no longer necessary.
Another difference between STC and STC-II is that the STC-II uses NI TIO-style counter/timers. For that reason, the NI 660x RLP manual ( http://digital.ni.com/manuals.nsf/websearch/4CE1C778F442B01386256C870060F9F3 ) would be a good reference for M Series counter/timer operations.
How would I start/stop acquisition
Assuming you don't need an external start trigger, you only need to write to the strobe bit AI_Command_2->AI_START1_Pulse. This will create a single start trigger pulse internally. The differences between AI_START1 and AI_START are described in the STC Technical Reference Manual.
A finite acquisition would be stopped automatically by the AI timing engine based on the number of samples you program via the method shown in aiNumberOfSamples(). Continuous AI would be stopped by first stopping the DMA operation and then calling aiReset().
I would guess getting the status of the FIFO and accessing the FIFO is a matter of reading the AI_STATUS_1 and AI_FIFO_DATA locations
Yes, this would work but I would strongly suggest using DMA as shown in aiex3.cpp. If you want to use "programmed I/O" to read the FIFO data directly, that method is shown in aiex2.cpp
Would looking at the Register Programming Manual for the "E" Series help me or just get me more confused?
In many cases it would be very helpful. See my comments, above.
I have inherited code that works on 65xx cards which I am pretty sure uses windowed mode that I am using in this 6221 driver. I have found that I can set the PLL registers to act as DIO and I can read the Discrete inputs just fine. Makes me curious, if Windowed mode is not used doesn't that mean the addresses are relative to the BAR1 address? Why then am I able to read the DIO?
I'm not sure why this would work- it's possible that some legacy functionality is still working due to the way you access the hardware in your code. For full functionality with M Series you must use mapped memory I/O to write and read from the device's registers.
Also starting with Clock_and_FOUT according to the example I set it for Slow_Internal_Timebase. But when I read back that Address it is always zero. According to the register map it is a "write". Does that mean I can't read it's contents? Or do I seem to have a problem because I am trying to use windowed mode with this card.
Yes, the "write" registers are write-only and the "read" registers are read-only. The effect of data read from or written to "write" or "read" registers, respectively, is undefined.
Hopefully this helps-
Tom W
National Instruments

How can I syncronize the analog input?

The signal coming from the microphone input of the DSP module, displayed on Waveform Graph, is "slipping".
How can I syncronize the analog input?
Thank you!

Ahh! You are doing this on the DSP itself. That would explain the Express VI problem, since you probably do not have floating point available. A simple level trigger is not hard to code using integer math. You can use the VIs I mentioned above as a guide (the algorithms should work well with integers as well as floating point) or just do it yourself. A possible algorithm for a positive going edge trigger is the following:
Search array until first point is less than level and second is greater than or equal to level (use In Range and Coerce to search).
Extract array subset from your data starting at the point you just found.
If you need a particular length of data and are continously acquiring, append data from the next scan onto your data until required length is met.
If you run into issues, let us know. Remember that shift registers are your friend.
This account is no longer active. Contact ShadesOfGray for current posts and information.

Getting an error 33162 when trying to read analog input on FP

I am getting a error when trying to do a simple analog input read using Field Point. I have a FP-2000 network module and am trying to read channel 0 at FP-TB-10 @3 which has an AI-C420 analog input module in place. There is no definition for the error and I can read the signal from Field Point Explorer just fine.
I have downloaded the example continuous read vi from the web site and it does not work either. It seems that this should not be complicated but this is not the 1st problem I have had. I will take any suggestions. Thank you.

Mike,
Error code 33162, "Can not connect to item on module," generally is the result of attempting to connect to an item that is not available at the first connection attempt. This is frequently the result of an ethernet network module being offline when you attempt to connect to it. Since you are able to connect from FieldPoint Explorer, I suspect something else is going on. The likeliest possibilities that I can think of are:
1) You have more than one ethernet Comm Resource in your IAK file and you have provided the name for the wrong resource (e.g. you may have had a different IP address and created a new Comm Resourcefor the new IP address, but left the old one in place and are using the wrong one).
2) Similar to #1 above, you changed the IP address in
the Comm Resource but did not save the change so there is no module at the IP address it is attempting to communicate with.
3) There is a misconfiguration in the IAK file and the FP-TB-10 shows a listing for a digital module at address 0 rather than an analog module.
4) The module is misaddressed. I have occasionally seen instances where the protective end cover was not installed on the last terminal base and a piece of metal shorted some of the pins causing the addressing to be incorrect. Since this method of failure would also show up in FieldPoint Explorer, I do not think it is likely the root cause of your problem.
5) You have booted the FP-20xx in Safe Mode (although FieldPoint Explorer will not work in this case so I do not think it is likely).
Note: If you had successfully connected and then lost the connection, the error code is 33163, "The connection to the module has been broken."
Regards,
Aaron

2 analog input and 1 digital

hi,
i attach the vi..
in the following vi i have a problem with the analogs..
when i'm running the vi.. At the results.. olly one of the analog will show me the measuerements..
at the one time maybe the clock analog will give me the results..
and the other analog nothing.. and opposites..
why they don't work together? and and the 2 analog give measurements at the same time..
andrikos
Attachments:
2_analog_and_digital_inputs.vi ‏190 KB

Hello Andrikoscy,
For most multi-function DAQ boards what you're trying to do is not possible. If you want each analog input to run on a different sample clock then you'll need to look into a NI R Series Intelligent Data Acquisition Device. These DAQ boards have a built in FPGA and allow for more customization than M Series boards, including independent sample clocks.
To address your questions:
1. On a non-intelligent DAQ board all analog input channels must share the same sample clock--if you need two different rates I would suggest sampling both channels at the faster of the two frequencies and then just ignore some of the data points on the slower channel.
2. In order to find out the exact time between samples from an external trigger (instead of the constant dt inserted by the waveform acquisition), you will need to take a period or frequency measurement of your signal using a counter on your card. By taking a buffered period measurement you will get an array of the times between samples and with that you can graph your samples on a precise x-axis. Normal analog input tasks that use an external clock do not associate any exact timing information with when a trigger was received.
I hope this helps, and if you'd like more information on the R Series Intelligent Data Acquisition Devices please feel free to contact National Instruments directly at www.ni.com/contact.
Have a great day!
Brooks

Trig an analog input with NI6115 through digital data sent by NI6534

Hello,
I have 2 NI cards: NI6534 (master), NI6115 (slave)
I have succeeded to do the following point:
The slave wait a trigger given by a generated pattern data through NI6534 to start an analog acquisition
(I noted that the start of the analog acquisition is delayed by 100 ns, is that normal?)
Now I want to delay the analog acquisition (let's say by exactly 5.0 microseconds)
Any idea how to do that
Loranger

Loranger,
The delay you are seeing is expected. When using a trigger pulse to "trigger" acquisition on another card, there will be a small delay. Usually the card will actually "trigger" within 1-2 ticks of the timebase clock after the trigger pulse is received over the RTSI line. 2 ticks of the timebase on the NI6115 (timebase of 20MHz) corresponds to 100ns.
In regards to delaying the analog input aquisition; this is what I would suggest. I would have the trigger from the NI6534 go to a counter on the NI6115. You could program the counter to generate a delayed pulse (5 us) when the trigger from the 6534 is received. The output of the counter could then be used to trigger the analog input acquisition. This should work for you. I hope this helps.
Todd
D.
National Instruments
Applications Engineer

What is the Fieldpoint analog input interchannel skew time?

I need to know what the interchannel skew is on Fieldpoint analog input modules because I need to aquire samples fairly close in time to one another simily to the typical MIO PC-based card. Also, I am wondering if the aquisitions can be externally triggered.

The FieldPoint IO modules are designed to continually sample all (4/8/16) channels and write the data to shared memory. FieldPoint controllers then read the shared memory and make the data available to the user (serial/ethernet) or controlling program (RT). There are no provisions for external triggering of ADC conversions. Nor are there provisions to prevent the user from oversampling or undersampling the shared memory (e.g. the controller reads the shared memory 5 times in-between the ADC updating a channel). The interchannel skew can be determined by taking the IO Module All Channel Update Rate (e.g. 1.08 seconds for the FP-RTD-122)and dividing it by the total number of channels (e.g. 8 for the FP-RTD-122). Thus, the delay in between any two adjacent channels
is 135 ms for the FP-RTD-122.
Ultimately, FieldPoint was designed for single point measurements and not for waveform or simultaneous measurements. The capability for triggered, simultaneous or deterministically sampled readings is not currently available in the FieldPoint system.
Regards,
Aaron

Analog Input (AI 112) con Filed point

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