Encoder edge counter using analog input

I have using an 9215A USB (4AI).
2 AI are logging data in to a txt-file and the other 2AI will be used for counting the edges from a quadrature encoder (A and B pulse train).
Every edge falling or rising I will write a line in the txt-file also show a egde counter in the VI (total edges read).
I'm a beginner so I need some help to find out how to do.
BR
Johan

the 9215A do 20kSam/s , that not too much, so .... your encoder should change state 10k/s max.
first approach: continious read (with max speed) with two buffers, while one buffer is filled by the DAQ, analyse the data of the other. Three independend loops : first wait for and read buffer-> send data via queue to second analyse loop -> send data via second queue to third loop that does the file handling.
second approach: create a trigger so the second loop can be avoided. The DAQmx/Hardware does might not support the trigger on both edges on two channels, but additional hardware like LS7084 o. HCTL2022 can help you to create the trigger signal. These little bugs are designed for incremental encoders and create a pulse for every change in the A B lines
Greetings from Germany
Henrik
LV since v3.1
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Have you looked at the specs for the device? The max sample rate and the max counter input will be listed there. The max frequency for an analog input is based on nyquist sampling theory. Are you at all familiar with? It states your sampling frequency has to be at least twice the frequency you are measuring.
Since each device might have a different max sample rate, your last question is answered.

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Alan;
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In our lab, we have a DAQ 6259 card. previously someone made a c++ programme. Now , i want to use labview to counter . but even i use the example(count digital edge), i cannot get the counts . So i tred it on test panels. only if the edge source is gate input(PFI9), it works. I am wondering what is the problem. could you give me some suggestion?

hi, yao yong, you should read about the configuration you are choosing, the only situation i have seen about using a gate terminal as a input pin is when you signal is too slow and you're measuring frequency, you should try what Kwok How says about try counter input 0 or try daq assistant.vi
Kwok How, i want to ask you or someone else if edge count or frequency measurement recognize every edge ( like noise-generated edges ) or just edges between 0 and 5 volts
best regards
.:. Pedro Rivera .:.
i love to work and develop on labview, this is real fun!!!

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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

Error -200072 using analog input with 3 PXI 6120 cards on realtime mx system

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Is there and easy way for Position control using analog input?

Hi Everyone,
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Hello Andras,
please use the link below to get the motion example.
http://zone.ni.com/devzone/cda/epd/p/id/353
Kind regards,
Elmar

Use analog input as sample clock

Hi,
I have a PCI 6115 DAQ card. I currently perform an
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sometimes, my clock signal is not high enough and the acquisition does
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plug the clock on analog input (say ai1), the clock signal gets
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Attachments:
AI - External Clock Using Analog Trigger Circuit.vi ‏81 KB
AI - External Clock Using Analog Trigger Circuit.JPG ‏60 KB

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Hi labview1958,
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How do i develop code in LabVIEW 7.1 for configuring and performing gated edge counting using NI-DAQmx

Hi,
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Thanks,
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There is an example that demontrates how to do this in DAQmx called "Count Digital Events-Pause Trig.vi".
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Attachments:
Controlled_valves.vi ‏192 KB

Here's a version in LV 8.0 and an image of the block diagram, for those running older versions of LabView.
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Attachments:
Controlled_valves.vi ‏207 KB
Block diagram.JPG ‏177 KB

How to use both digital and analog input modules in the same worksheet - MCC USB1208LS

Dear all,
Hi, I am Imran. I am using MCC USB1208LS. I have created the worksheet using digital input module as below and able to execute (run).
But when i add another analog input module in the same worksheet and executes, An error Message pops-up as in the below image
I have connected temperature sensor sognal to the analog input of USB1208LS. When using analog input alone in the worksheet, it indiates the actual values.
is any black box solve? please guide me. I am attaching in images
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Thanking you,
Imran Mohamed.
Attachments:
present worksheet digital input only.JPG ‏67 KB
with analog input module.JPG ‏81 KB
error menu.JPG ‏77 KB

Hello Imran,
the USB-1208LS is not capable of running concurrent operations such as an analog input scan and ANY digital Ins, Outs, counter reads, or analog outs. In Dasylab, the 1208LS is scanning, and nothing else from that particular device can be requested of it while that is happening.
Yes, using the 1208FS will resolve some of these issues.
Please refer to the ULHELP.CHM file installed on your computer in c:\program files\measurement computing\daq for details on this issue, et al.
also I recommend you send your MCC/DASYLab requests for support to [email protected] as MCC staff (that includes me) does not normally monitor NI's Developer Zone.

Event counter using USB-6210 analog

Hi,
Any suggestions or directions where to look to generate a VI that would record event from a magnetic counter of a mouse wheel. I would like to record up to 16 wheels using the USB-6210 device. Thanks!
VO2max

Thanks for the extra information.
The 6210 actually has two counters, so you could count the edges (on two of the wheels) if the signals are TTL compatible. You can use the Count Digital Events.vi example to help you get started. From LabVIEW, it can be found at:
Help » Find Examples... » Hardware Input and Output » DAQmx » Counter Measurements » Count Digital Events
If your signals are TTL compatible, I would highly recommend purchasing a PCI-6602 and using this method for all 8 channels. You could modify the example code by increasing the delay (software-timed sample rate) to a larger value (say 1 minute), and logging the results to a file as you run. Doing this would log the value of the event counter every minute, and would keep the file size relatively small (about 15kB if you run for 8 hours).
If you must use a single 6210 and require all 8 channels, the only option would be to use continuous analog inputs. You would have to sample at a high enough rate to not skip the pulses (I am not sure what that is without knowing more about the signal), and then process the digitized signal in software to determine the information that you need. I would use the Producer/Consumer design template in conjunction with a continuous analog input example to get started. In the consumer loop, you would have to implement the functionality of the counter in software.
Using a hardware counter would be preferrable to using analog inputs. The counter is made for exactly this type of task, and implementing it in software can be complicated as well as processor intensive. If you have any questions let me know, I'm happy to help you out. You can always try out the counter task on the 6210 for two wheels to see how it will work before deciding whether or not to purchase a new board.
-John
P.S. After your first post I had assumed that you were testing computer peripherals, but it looks like you actually have eight rodents. We had a good laugh over here over my confusion.
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How to use counter using PCI 6259

Hello, users,
I have a PCI 6259 board and use Labview 7.1.
I'd like to repetitively count the photon signals at 10ms integration time. I want cumulative counts in every 1 sec (1000ms) (or 1 min (60000ms)) And I want to save counts into txt.file which is open in excel program.
I am a beginner to use counter using PCI 6259 board.
1. Could you explain default NI-DAQmx counter terminals, i.e., CTR 0 SRC, CTR 0 GATE, CTR 0 AUX, and CTR 0 OUT?
2. How do I use them or how can I connect to count TTL pulse using PCI 6259?
3. As I mention my purpose above, which example is the first step to start working my purpose?
4. If you know good example, could you tell me about that?
5. If anyone has labview example which is similar to my aim, could you give me some tips or your examples?
Any hint, comment or advice would be appreciated.
Thank you so much for your response.
Leek2

I have never used the PCI 6259 but have used counters many times with labview, the coding should be the same independent of the board. What you want to do is finite buffered edge counting using a internal clock. The best way to do this is to look at the examples programs and use the express vi to get started, then you can use this code to customize your program exactly as you need.
To address your questions:
1. CTR0 means "counter 0" the name of the physical resource sometimes listed at GPCTR0. Each counter has 4 connections to the outside world:
source "src"(for counting input TTL signals),
gate (for synchronizing to external clocks and edges),
out (for pulse-train out operations)
and aux (specialty operations such as up/down counting and encoding)
2.For event counting with internal clocking you will only use the src this is the input from the signal you wish to count (ie PMT discriminator for photon counting).
3,4,5. Look at the count edge examples, there isn't one that does exactly what you want but I have done this with a 6602 (it has e counters) where I use one set of counters to set up a finite pulse train in your case 1000Hz with 1000 pulses, and another counter to edge count on an external pulse, with the source of this pulse routed from the out of the other counter. Then you can start the task and read when 1000 samples are in the buffer (about 1 second later).
Hope this helps,
Paul
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA

Triggered and continuous analog input togeather?

Hi,
I have a program set up based off a shipped LV example involving digital triggering of the analog inputs. It looks at a pulse and reads in ten points from the rising edge continuously. It appears that we are missing some pulse triggers and only reading in 126 triggers/sec instead of 128. We double checked the pulse and the frequency is correct (128Hz) so it seems as if the LV program is missing some of the pulses. Therefore, I want to use another analog input channel on the same 6062E daq card to continuously read in the waveform and see which pulses are being skipped. Is this possible?

Lisa,
I don't believe the E-series architecture will allow triggered and continuous analog input operations to occur in parallel. It is possible to set up different gains/input ranges but I'm 95% sure that the functionality that you are after isn't there.
If you are looking to keep track of the number of pulse seen by your application you could consider the use of a counter to count the number of rising edges seen by the NI 6062E - basically daisy chain the pulse train to the trigger input and the GP_CTR Source pin of the counter you wish to use. There are a number of examples around that should help with this. Running the counter and analog input operations in parallel shouldn't be a big problem - it might be that you would want to set up a buffered event co
unt operation for the counter as this will allow you to track and monitor every single trigger event seen by the counter while your analog input operations continue in parallel.
The other aspect to consider is benchmarking your application with the Profiler. If the problem is that you consistently only see 126 triggers/second, perhaps your acquisition loop is not running fast enough to cope with the data. This can be especially true if any data processing or file storage is taking place inside the acquisition loop. The Profiler will allow you spot bottlenecks and get a better understanding as to the performance of your application.
I appreciate this is perhaps not a direct answer but hope that it gives some ideas as to how to track down the cause of the problems you are experiencing.
Jeremy

Encoder edge counter using analog input

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