PWM with a SCXI-1200

I need to generate a PWM signal with a SCXI-1200 connected to a SCXI-1000 chassis. Any ideas of how to do it? I have a routine to generate a PWM to the PCI-6035E, but not for the SCXI.
Thank you,
Guilherme

Guilherme;
You can't do PWM with the counter that is on that module. There is only one register on the SCXI-1200 counter. Everything would be very glitchy and ill-timed.
In case you need to do that on SCXI, you will need a SCXI-1180 feedthrough module. That module allows one to access the unused counters of the DAQ device that controls the SCXI chassis.
Regards
Filipe A.
Applications Engineer
National Instruments

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Inability to install SCXI 1200 in Windows XP

I am trying to use some older NI hardware (SCXI 1000 chassis with SCXI 1200 connected to a parrallel port), and windows XP is unable to detect the hardware. I tried following the SCXI 1200 support pages, but when I enter the add new hardware wizard the 1200 module does not show up. There is a header titled Data Acquisition Devices, but I cannot find any SCXI modules. Are there additional drivers that I have to install for XP? I realize that the equipment is quite old, but I am trying to make everything work without breaking my budget buying new stuff.

Hi,
Unfortunately, the SCXI 1200 will not work with Windows XP. The data acquisition drivers that are required to use this legacy device are not updated for the Windows XP Operating System. I highly recommend upgrading to newer hardware which will allow you to use the newer DAQmx driver and the Windows XP operating system.
Regards,
Hal L.

SCXI-1200 ... Win2000 ... LabView 5.1 ... which NI-DAQ driver

Hello
we have a good running LabView program working on an old PC-system (Win-NT,
LabView 5.1 with NI-DAQ 6.1) together with or hardware,
a SXCI-2000 chassis with SCXI-1200 DAQ, and two multiplexers SCXI-1122 and
SCXI-1100.
Now we need a backup of our computer, but who will install Win-NT
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Hi Wolfgang,
Actually, the SCXI-1200 is not supported in Windows XP or 2000 by any of our drivers. As one of our legacy boards, it is only supported under previous versions of Windows, such as the NT version used on your old system. If you cannot use an older version of Windows, your best option will be to upgrade to hardware that works with Windows 2000. See NI-DAQ Driver Support for more information.
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Need to be Able to use a TB-1328 with an SCXI-1125

I need some labview code to show me how to read temp from a SCXI-1125 with a TB-1328 thermocouple on it. I have a K type thermocouple wire, I have to stick with Labview V7.0, NI-DAQ 6.9.3f5, and this is running on an RT machine using a PXI-1010 split PXI/SCXI chassis, with a PXI-6040E running the SCXI bus. Please if you could, tell me how to remote DAQ configure this. Thank you.

Hello,
If you have NI-DAQ 6.9.3 support installed for LabVIEW 7.0, then you should have an example which will show you how to acquire a thermocouple reading from a SCXI-1125. The example which I am referring to is called "SCXI-1125 Thermocouple.vi". Regardless of what terminal block you are using with the SCXI-1125, you need to make sure that you configure it accordingly in Measurement and Automation Explorer.
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Jared A

Generate two alternating PWMs with one counter of 6025E

I am using LabView 6.0.2 with a PCI-6025E card. My requirement are to put out a pwm signal with 250Hz. The problem is, that for example, first a PWM with exact 100 pulses of duty cycle 1% is needed, after that exact 5 pulses of 10% duty cycle. These two PWMs are repetetive without any big pauses between. I tried this with Pulse Train Generation with "Changing Pulse Specs.llb" from the ni libraries, but the PC based on windows is not able, to do the PWM changes in these exact time slots. Note: The second timer of the card is used for another item.

Unfortunately, you won't be able to do exactly what you want with a single counter. You'll need to use additional hardware. Here are some possibilities:
1. Analog Output:
A 1% duty cycle at 250 Hz requires a minimum of 25 kHz update rate, but your 6025E only goes up to 10 kHz. Your board is also limited by having only 1 DMA channel for Data acq buffered operations, and it may already by used by your other counter's operation.
If you had an analog board with faster output, you could try to create a buffer with 0 V and 5 V values representing the desired finite pulse train. However, if the device you're controlling with PWM requires TTL edges, the rise and fall times of your DAC output may still not be fast enough to fool it.
2.
PCI-6601/6602 Counter/Timer:
You could use two counters from a 6601 to generate the finite pulse trains you describe, but there would need to be a pause between the the two duty cycles. The pause is where your software detects the end of one finite pulse train and reprograms the counters to generate the other one. The pause might likely vary from 10 to 100 or more msec.
If that variable dead time between pause trains is acceptable, the 6601 is the cheapest solution I know of for today's application. If you need reuse for future apps, you might want to consider the 6602 for double the price, but a bit more than double the capability.
3. PCI-6533/6534:
NI's timed digital boards would allow you to define the pulse trains as a one-bit digital pattern that you could generate continuously. I suspect the 6533 would suffice for the app you describe.
Please double-check these hw suggestions with your local rep before ordering. (S)he'll know more than me about
your present-day app and potential future needs. Good luck!
-Kevin P.

PWM with CompactDAQ 9174 on a DO-Module

Hi all
We did a regulation of peltier elements with PWM with a cRio over FPGA on a DO-Module 9477.
We have now a small project with a CompactDAQ 9174 where we would like to regulate such peltier elements. The Frequenze should be at least 5 kHz.
As I found in the forum and the examples, with the intern counter/timer of the cDAQ9174, it is possible to generate a digital pulse train and with the duty cycle also a PWM.
e.g.:
http://forums.ni.com/t5/Counter-Timer/Counter-Output-with-NI-cDAQ-9188/m-p/2218208#M10898
http://digital.ni.com/public.nsf/allkb/ADFC4DD8C9690232862575B70079FBD4
What I could not found, is a way to get a generatet PWM-signal out of the intern cDAQ to a DO-Module (S-Serie) such as NI7477. And I do not see the way to do it.
I have to mention, that I'm not a top-programmer, and I'm sure, that there is somone out there, who already has done this.
Thanks in advance for help
Hannes Wydler

Hi Abduelkerim
Thanks for replaying
As far as I see, the forum discussion you mention, talks about measure PWM (Digital IN).
I found an other forum input (how to pwm out on NI-9477):
http://forums.ni.com/t5/Digital-I-O/how-to-pwm-out-on-NI-9477/td-p/624448
There Application engineer Samantha says, the NI9477 is not a "corelated" digital module and therefor it cannot link to the backplane counter of the cDaq. Others DO-modules could do that (like 9401).
But what we need is the high power of the 9477 (1 Amp per channel - I would connect 3 outputs together for my need of 2.5 Amps).
I don't find in the specifications of the different DO-modules if they are "corelated" modules.
It seems, it's not possible what I want to do - a simple direct mode with the cDAQ to supply and regulate peltier elements.
Hannes

Will Analog Instruments ADXL330 triaxial accelerometer work with the SCXI-1531 input module?

I have an SCXI-1001 chassis and will soon be purchasing an accelerometer input module (SCXI-1531). I'm also investigating possible accelerometers to buy. Does anyone know if the the Analog Instruments ADXL330 accelerometer can be made to work with the SCXI-1531? Here is a link to the Analog Instrument's page about the device:
http://www.analog.com/en/sensors/inertial-sensors/adxl330/products/product.html
Thanks!

Hello,
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High Speed Digital I/O Product Support Engineer - R&D

Measure PWM with CRIO Module 9403

Hi,
I'm trying to measure a PWM signal generated by an absolute encoder. The encoder outputs a PWM with a period of approximately 1000 microseconds. This correlates to about 0.4 deg/microsecond.
When I run an FPGA code that has a counter that counts ticks while the PWM is high, the counter takes approximately 265 ticks per loop (and increases when other I/O readings are made) - according to the benchmark timer I've incorporated into the code. This means that the loop requires about 6-7 microseconds to take a reading from the DIO. This correlates to a couple of degrees in resolution which is not a good enough for our application to read from the encoder.
Is there any way to increase the speed of the FPGA? I've included a screenshot of the FPGA code as well as the project containing the test VI.
Attachments:
fpgaproblem.jpg ‏65 KB
testfpga.zip ‏21 KB

Hello NIo33,
Have you benchmark the rate at which the PWM signal is coming in from the NI 9403 module? What type resolution are you trying to achieve? I do not see to many ways to pipeline your FPGA code.
Paul-B
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National Instruments

Does the "get SCXI information.vi" supports comunication thru SCXI-1200?

I'm trying to get the chassi modules and configuration information thru this VI using a SCXI-1200, but it returns the status -10240 and no information.
Please send any answer to: [email protected]
Thanks in advance,
Leandro Fonseca
FSE - NI Brazil

The Get SCXI Information.vi will return a 51 for the module type. Note that I do find it odd that the help for the VI states that anything not on the (limited) list of SCXI modules is not supported by that version of LabVIEW. I'm using 6.1!
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Cheers,
Daniel L. Press
PrimeTest Corp.
www.primetest.com

Read duty cycle of a PWM with DAQ

Hi,
I am doing a test system and I have several signals that control motors. They use PWM with a max frequency of 5 kHz.
I would like to know if with a USB DAQ or a PCI DAQ for example PCI-DIO96 could I meassure the duty cycle of these PWM signals. I mean I need to meassure with 10kHz at least.
Which are the read frequency of these systems?
Due to the high number of I/O to test I am also thinking of using Compact-RIO with different I/O modules. What do you think?
Thanks in advance

If your PWM frequency is 5 kHz and you want to measure duty cycle to 1%, then you need timing resolution of 2 microseconds or faster.
The USB-6343 has hardware timed DIO at up to 1MHz, so it might be suitable. There are other devices with hardware timed DIO at rates of 10 MHz or faster as well.
Before you buy, determine how often you need to measure the duty cycle to make sure the data transfer can keep up. USB can sometimes be a bottleneck.
Lynn

Connecting a BNC-2081 to an SCXI 1200

I have a strain gauge connected to a SCXI 1321 block, connected to a SCXI 1121 Module, connected to a SCXI 1200 Data Acquisition board and SCXI 1000 Mainframe. I am trying to connect a BNC 2081 to the SCXI 1200 to be able to acquire the data over a standard BNC connector. However, I connect everything, verify the BNC 2081 has power, but still get no signal out of any of the 4 channels acquired by the SCXI 1321. Does anyone have any solutions?
Thanks

Hi rsmcculloch,
Lets first start by verifying you can get a signal into the
computer. Please check the test panels in Measurement and Automation Explorer
for the 1200. Do you get any errors? Was this card working before? This
knowledgebase :Testing Your SCXI-1200 System
will also help you out.
David L.
Systems Engineering
National Instruments

Can I install SCXI-1200 and other NI-DAQ devices on the same computer?

I have the following three devices connected to my computer right now: PCI-MIO-16E-1, AT-MIO-16E-2, SCXI-1200(connected to SCXI-1001 chasis).
For some reason, the 2 E-Series devices (PCI-MIO-16E-1 and AT-MIO-16-E-2) function properly, while the SCXI-1200 always times out when I try to test it. (a base address error is returned). I tried all the trouble shooting procedures listed in this website but didn't succeed.
Is there a compatibility problem between the devices?

Hello;
The main question is; did you try the scxi-1200 by itself on the machine (without having the other devices hooked up to the machine)?
It's important to narrow down the problem to a multidevice compatibility problem or a SCXI-1200 problem.
Regards
Filipe A.
Applications Engineer
National Instruments

PWM with Duty Ration on three LED's - driven in sequence

Hello
I write an example of fade-out and fade-in for single LED. A hardware clock which is routed to DO is used. The Diode will constantly fade-out and fade–in where steps and times can be adjusted. For single LED this works perfect. An M or X series DAQ is predicted (USB M 6251 or USB X 6351)
The problem is that in real application (User Interface (UI) with LCD) a three LED’s will be used, which are connected on three lines and only one LED is active at a time (to reduce the cables two LED’s are connected in opposite direction). PWM frequency will be 1 kHz and each 10 ms next LED is active (cyclic trough LED each 10 ms: LED1, LED2, LED3, LED1, LED2, …………. ……). Schematic is attached and is fixed (also some pushbuttons are connected but they are not relevant at the moment).
Could you give me some hint or similar example how to transform/multiply this functionality (PWM with Duty ration) to three LED’s (which are works in sequence) with hardware clock of 1 kHz. Timing must be precise, since user should not detect any flickering on UI.
Attachments:
3x_PWM_cyclic_V1.vi ‏40 KB
Schematics_3xLED.PNG ‏26 KB

Dear RomanP,
I'd recomend using the X series device for this application, since the STC-3 timing chip enables you to use buffered pulse trains. The idea is that you can use a FIFOto store duty cycle information for every single PWM pulse. The device will use one sample to generate one pulse, then continue on to the next one. This allows you to have three counters working at the sae time with the same clock source, but with a different pwm data (one will always do the fade-in, fade-out routine, the other two can generate a 0 duty cycle signal).
Here's a community example you can start to work with. Let me know if you have something else in mind.
Kind regards:
Andrew Valko
National Instruments Hungary

Scxi 1200 AOs togheter with other AI modules

Is it possible to use the analog output and the trigger of the 1200
module simultaneously with the analog inputs of the 1125 amplifiers (or
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Thanks.
Marcos

Hi Bipin,
Looking at your code, I see that you are still using Traditional DAQ. Since you have LV 7.1, you can take advantage of the new features of DAQmx.
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To do this, open up the Measurement and Automation Exlporer (MAX). Select "Data Neighborhood" from the tree on the left. Then click the button labeled "Create New." Create a DAQmx Virtual Channel. Follow the series of menus to set up your first type of acquisition (1126 frequency measurement). When you are
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Once they are set up, save the task and open LabVIEW. Place the DAQmx Task Name constant on your block diagram found in All Functions >> Data Acquisition >> DAQmx... the task name constant is a purple colored box. Clicking on the box once its on the block diagram will expand a menu that will let you choose your task. Once selected, right click on the task name and choose Generate Code >> Example. This will automatically generate the code necessary to run the tasks. Simply hit the run button and enjoy!
Thanks,
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Pulse width modulation with a PCI 1200 board

Hello,
I Have a PCI 1200 board and I try to generate a pulse train with a period
of 500 ms and a variable duty cycle between 10% and 100% by step of 10%.
Does anyone know how to do this.
Thanks in advance
Michel Kocher

Does this help?
Attachments:
PWM-Counter_Output_Folder.zip ‏63 KB

PWM with a SCXI-1200

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