System Identification Assistant w/o NI Signal Generator

Hello,
I am using a GW Instek power source to heat a graphite rod within a vacuum chamber. I am detecting the temperature with a K type thermocouple connected to a thermocouple input module. I have written a labview program with a PID and have everything running, yet i force tuned the PID. I would like to use the signal identification tools labview provides to identify the transfer function and model the process. I have used the system identification assitant in attempting to send a step signal and acquire a response, yet I have been running into difficulties. The only way I can perform a step function is to manually generate an output of a specified power and then measure the response, as the signal generator within the system identification software is not identifying the GW Instek PSW 30-108 power source. With manual input and importing both input and output data i am able to get a parametric model, yet the transfer function provide me PID values which are 5 orders of magnitude greater then the ones i am currently using. Ideally i would like to use the software to generate the signal and measure the response continuously rather then using data i collect through my program. If possible, I would also be interested in perhaps directly integrating VI's to perform signal analysis directly into my process program.
Problems and what I have done:
I have the drivers for the power source and my process program recognizes the device yet system ident assist cannot find the hardware. I have attempted to creat a task in NI-MAX yet the hardware is also non-identifiable.
Port module input works with VISA and this is how my VI is communicating with the power source.
Goals:
I would like to use the system ident assist to generate power ouput and collect temperature input, and generate a process model, so that I may tune my PID more accuratly.
Also, I may be interested in integrating VI's directly into my process program, yet I am new to the LV language...
I have attached my Labview program below. I would like to thank you in advance for your time and look forward to responses.
Cheers
Attachments:
Test1_RT.vi ‏186 KB

Using cDAQ 9171 interface to accquire thermocouple data. My Device does appear in MAX under devices and Interfaces, and i set up the Port/Visa for my LV program. So LV program recognizes the power device, although System Identification does not give me the option to access the device for signal generation. I have tried to set up a task under device neighborhood, and have alse attempted and IVI device session setup. Both unfortunately did not get me any farther. I am thinking i may have to right a program with VI's and integrate it into my current LV program. Although I dont want to attempt to do this until I am certain that I can get the System Identification VI's to recognize the Power Supply. Ideally I would like to avoid contructing a program and simply use the system ident assisten and parametric modeling to provide me the T.F.

Similar Messages

System Identification Assistant Signal Generator

Hello,
I am using a GW Instek power source to heat a graphite rod within a vacuum chamber. I am detecting the temperature with a K type thermocouple connected to a thermocouple input module. I have written a labview program with a PID and have everything running, yet i force tuned the PID. I would like to use the signal identification tools labview provides to identify the transfer function and model the process. I have used the system identification assitant in attempting to send a step signal and acquire a response, yet I have been running into difficulties. The only way I can perform a step function is to manually generate an output of a specified power and then measure the response, as the signal generator within the system identification software is not identifying the GW Instek PSW 30-108 power source. With manual input and importing both input and output data i am able to get a parametric model, yet the transfer function provide me PID values which are 5 orders of magnitude greater then the ones i am currently using. Ideally i would like to use the software to generate the signal and measure the response continuously rather then using data i collect through my program. If possible, I would also be interested in perhaps directly integrating VI's to perform signal analysis directly into my process program.
Problems and what I have done:
I have the drivers for the power source and my process program recognizes the device yet system ident assist cannot find the hardware. I have attempted to creat a task in NI-MAX yet the hardware is also non-identifiable.
Port module input works with VISA and this is how my VI is communicating with the power source.
Goals:
I would like to use the system ident assist to generate power ouput and collect temperature input, and generate a process model, so that I may tune my PID more accuratly.
Also, I may be interested in integrating VI's directly into my process program, yet I am new to the LV language...
I have attached my Labview program below. I would like to thank you in advance for your time and look forward to responses.
Cheers
Attachments:
Test1_RT.vi ‏186 KB

Double post, for further Information see http://forums.ni.com/t5/LabVIEW/System-Identification-Assistant-w-o-NI-Signal-Generator/m-p/3014731#...

Need help with control system that reduces a flat output signal every time a certain input exceeds given value

I'm having difficulty setting up a closed loop control system that reduces one of my voltage outputs (connected to a high voltage system) by 30% every time a measured voltage exceeds a certain threshold value. I'm using a USB 6229 DAQ. I've been trying to create a waveform that looks like a DC signal, but the only waveforms that I can seem to manipulate while my VI is running are the stock waveform types. Also, I've tried to use a formula node or conditional structure to update the output value every time the measured voltage exceeds a given value, but everything I do reinitializes the output value every time it runs or won't store the previous signal value. I'm using LabVIEW 8.6 and don't have the PID or similar express VI's. I've attached the mess I've got working right now. Can anyone help? I'm really stuck!
Thanks!
Attachments:
HiV step down.vi ‏40 KB
output control.vi ‏100 KB

I'm sorry it's such a mess; I'm still pretty new at this. These are both little driver programs for a larger overall control program.
Output control is meant to send a flat signal to the DAQ whose value can be manipulated while the VI is running. I have the second activated segment merely to check the values being output. I didn't realize I attached a version with a meaningless control...I had a control where the user would put in the stating voltage (the high voltage source has a 1V-100V setting for external control). I've attached this slightly different but equally dysfunctional version. Ideally, I would have liked something like the analog signal generator vi to come with an input wiring for offset on the DC signal. Most of the code was diabled because it is copied from an example; it is largely rubbish. I initially used the DAQ Assistant, but when things weren't working out I switched to putting in each step manually to try to troubleshoot.
As far as HiV step down is concerned, I've tried something different with a nested case structure (if that's the right terminology?), and I've attached that file. I think this problem has been solved, but you never know!
Attachments:
output control slightly different.vi ‏100 KB
HiV step down w case structures.vi ‏44 KB

Can i connect an external signal generator to the NI7344 to...

Can i connect an external signal generator to the NI7344 to use its
PID characteristics to precisely control the output
I am using the flex motion board (NI7344) to control the force output
of a linear motor. Using contouring and buffer operations i have
successfully created a system which can output a controlled force
which sinusoidal in form. I can achieve a reasonable output for
waveforms of 10Hz, the use of higher frequencies is limited by the
contouring operation ( a frequency of 10 Hz means i can only describe
one period of a sine wave with 10 points ( 10ms between each point =
10Hz). Can i therfore connect an external anologue wave generator to
the NI7344 use and use its PID characteristics to output wave
forms of
higher frequency ??? .....could i output an anolgue wave form from an
E-series DAQ via the RTSI cable to the NI7344 and control this ???.any
ideas or advice would be much appreciated.

Duncan,
You can use a DAQ card to output an analog waveform, but it will be a software call not part of an onboard program. RTSI can be used to pass clocks and trigger signals, so if you want to route a clock signal to do the control you could.
A. Talley

System Identification with Digital System

Hey,
So when using the system identification toolkit, the user excites the system with a analog signal. After they're finished with the entire process they're able to get a plant model of their system. So what if they're system will be using digital inputs/outputs (e.g. a digital amplifier on their proportional valve), can their system be excited with digital outputs and then achieve a digital plant model? Or must their system be an analog system to use the toolkit?
Thanks

If your search didn't turn them up, then you probably have the base package of LabVIEW and the functions are not included. The search function is at the top of the functions palette.
You can use either function provide data to a DAQ output. If you want to use an analog output, you just have to wire the waveform to a DAQmx Write. Look at any of the shipping examples for DAQ output. Most of them use waveforms such as a sine wave but it doesn't matter. Waveform data is waveform data.

LabVIEW drivers for Agilent Noise Source 346B and Signal Generator E8257C-520

Could anyone please tell me where to find LabVIEW drivers for Agilent Noise Source 346B and Agilent Signal Generator E8257C-520. I did not find them on NI's web site. Thank you!

To my knowledge, the Agilent 346B Noise Source is not a programmatically controllable instrument and therefore we can't create an instrument driver. I suppose it is possible to be controlled through an instrument (like the PSG) but I don't see any documentation on this.
As for the E8257C, we are insterested in providing a LabVIEW driver for this instrument series. Let me know if you are interested in assisting our development effort by loaning us the instrument.
Jason Hobbs
Instrument Drivers

Signal generator fo usb-6211

Hallo, I'm in the process of generating square wave with adjustable duty cycle for my usb-6211. After searching, I find two generators available: IVI FGEN, and DAQ Assistant. The latter seems suitable to my device, but without capability of changing duty cycle. Consequently, I'd love to know whether there exists any kind of signal generator which yields up square wave with adjustable duty cycle and whether it is feasible to connect it to DAQmx Write to feed to the signal to AO0/1 of my usb-6211.
thanks in advance,
win2

Hi win2,
you are right, the DAQmx functions are what you need. The FGEN drivers are only for the hardware based function generators.
As you mentioned that you use DAQ Assistant, I guess you use LAbVIEW (which version?) to try to produce the rectangel with adjustable duty size.
Right? Please let me know, which version of DAQmx you have installed on your PC, too.
Here you have two links, where you can find an example how to generate a squares with adjustable duty cycle using the analog output.
This example, i guess, is what you want to achieve:
http://zone.ni.com/devzone/cda/epd/p/id/5235
It shows, how to use software timing to adjust the duty cycle.
The second example shows, how to create a "selfmade" signal:
http://zone.ni.com/devzone/cda/epd/p/id/1621
If you want to send TTL signals, please keep in mind that you can use one of the four digital outputs.
Creating a digital pulstrain allows to set the duty cycle directly.
I hope, this helps
regards
Kilian

Configuring and Controlling Agilent 332220A signal generator...

Hello,
I am trying to configure and finally control Agilent 33220A signal
generator through my Labview VI. Signal Generator has USB, LAN and GPIB
interface. Measurment studio recognises it, however I need assistance
to proceed from that point. I would be happy, if some body can guide me
through this process.
Any online manual or user guide would be great.
Thanks in advance...
Shivaram

Hi Sine,
Just to recall what all I did,
* Downloaded agilent signal generator instrument drivers from the link given below.
       http://sine.ni.com/apps/we/niid_web_display.download_page?p_id_guid=E3B19B3E9066659CE034080020E74861
* Extracted the downloaded zip file to get a folder by name "ag33xxx".
*   Then copy paste this folder in the location given below.
       C:/Program Files/National Instruments/LabVIEW 7.1/instr.lib
*   That's it. You are done. Connect the signal generator either through USB cable or RS232 or via LAN.
*   Now you can communicate and control the signal generator
through the labview VIs. You can do so by right clicking in the block
diagram then, point to "Input", "Instr Drivers". I have attached a
screen shot of it.
* I have also attached a VI, which I have developed with the help of this form.
Hope this information helps...
-Shivu
Attachments:
agilent_signal-gen.jpg ‏78 KB

Question about the customized FPGA signal generator.

I connected the AO0 and AO1 ports to the oscilloscope. But I got nothing. What should I do?
Attachments:
Customized FPGA Signal Generator.lvproj ‏2159 KB

Hi CZ_Kevin,
When attaching a project, it might be best to zip the project folder, or attach your VIs, so that we can look at your code. As for the screenshot, it looks like you might be using too many resources on the FPGA but again it is hard to determine without looking at your code.
Since you are using a myRIO, you might get better responses by posting to the Academic Hardware Products forum as this handles many myRIO questions.
Also, there are many pre-built project templates and examples within LabVIEW that might be worth exploring as well as a project guide that includes many tuturials. You can find the latter here.
David C

How do I read in a 1 Hz pwr level file and send it out at 1Hz to the signal generator?

I would like to be able to read in a 1 Hz file and use the format into string and send it out at 1 Hz to a signal generator to vary the levels to match a timestamp. I was trying to use the format into string but I can't figure out how I could read in this file.
00:00.0
-113.586
00:01.0
-113.598
00:02.0
-113.61
00:03.0
-113.622

If the file is a .csv file as you said in your other post, then you should just be able to use Read From Spreadsheet File, making sure to set the delimiter to comma rather than tab. If it's a small file, you can just read in the whole thing, then use a loop with a Wait For Millisecond Multiple node (the metronome) to send the data once every second.
If the file is very large, and you don't want to read it all at once, you can tell the Read From Spreadsheet File node to read only one line at a time. Put the read node and the data sending node in the same While loop, and use a shift register to carry the Mark After Read value from one iteration into the Offset or Mark At Start terminal in the next iteration. That way, you start reading each line at the end of the previous one. Use some form of flow control (such as a Stacked Sequence Structure) to make sure things happen in the right order - read data, wait for the right time, send data.

System Migration Assistent - Migrating Vista-- Windows 7

T61 + Vista
When I receive Windows 7, can the ThinkVantage System Migration Assistant move current Vista settings to Windows 7 or does the utility only work within the same OS?
Thanks,
Mark
Moderator Note; edited subject for relevancy
Message Edited by andyP on 07-15-2009 09:45 PM

Yes Mark, It should be able to. I see why no reason why it shouldn't work.
Moderator Note; edited subject for relevancy
Message Edited by andyP on 07-15-2009 09:46 PM
Do NOT PM me with technical issues. Post in the forum for assistance. Thanks

System Identification and Transfer Function of the LEGO MINDSTORM NXT Robot

Can anybody please help with the below question.
Using your LabView interface, input different values of power and record the output value of the number of wheel rotations. You can convert the latter into speed by measuring the diameter of the wheel. Then, type ‘ident’ in the command line of Matlab to launch a graphical user interface for system identification. Using the data collected for input power and recorded speed, you can derive the transfer function for your robot in the Laplace domain.
You will notice that it is possible to approximate the transfer function to a first order system.
Add disturbance to your system such as wind drag, road profile or friction. You might want to model the disturbance as a sinusoidal waveform.
Analyse the system response in LabView in order to tune the response.
Finally, write a LabView program to test your controller.
Set both Integral and Derivative to 0
Increase the value for Proportional controller to 0.5, 0.8, 1, 1.1, 1.3, and 1.5
Select a suitable simulation stop time.
Compare each simulation results and draw some conclusions.
Record the steady-state error. Has it dropped to near zero?
Record the rise time. Has it decreased to less than 0.5 second? And for what values of Kp?
Check whether this response is realistic i.e. a real cruise control system generally cannot change the speed of the vehicle from 0 to 10m/s in less than 0.5 second.
Adjust the gain (Kp) to give a reasonable rise time and add an integral controller to eliminate the steady-state error.
Change both Kp and Ki and see what happens to the response. When you adjust the integral gain Ki, start with a small value since a large Ki can destabilise the response. (Ki =0.001, 0.002, 0.003, 0.004).
Then you need to adjust both the proportional gain Kp and the integral gain Ki to obtain the desired response. Record the values of Kp and Ki that can meet all the design criteria.
Write the PID-feedback control LabVIEW program as described above.
Does it work? Quantify! Show us it is working
Hand in a short report on the PID project on the cruise control of the LEGO MINDSTORM NXT Robot. Your report should contain an introduction to cruise control and uses of PID controllers, a brief explanation of how PID feedback control works. The printout of the Block Diagram and Front Panel of your LabVIEW program should be attached at the end of your report.
Put it all together. There are many questions that can be explored and written up in the result section. Be creative.
Here are some things that may be addressed: Check whether your system can stabilise speed to within 1%. What are the optimal PID parameters that you have found? Can you choose PID parameters to both reach the set speed quickly and also maintain the speed within good accuracy once the system has reached the set speed? Can you control the speed of small steps? Explain your results?

Thanks for that.
DanHarryman wrote:
HI ToolMonkey
You should be able to build control system to do this using PID control VIs. The following paper is a good place to start when working with PID systems.
http://www.ni.com/white-paper/6440/en
Let me know how you get on using some of the functions in this.
Thanks
Dan.H
UKAE

System identification of a "complex" system

I would like to use labview to extract the transfer function of a closed loop control system. This system uses a PID loop to control the amplitude and phase of a radio frequency cavity.
I can easily excite the real world system with a step response (or any arbitary excitation).
The step response from the system has both amplitude and phase, and in labview is an array of type "extended complex".
Is the NI system identification toolkit capable of extracting the transfer function in both amplitude and phase? I have an evaluation version and have been unable to get this working.
Pete.

System Identification uses frequency response based on "bode" graphs. This means that it has two graphs: one representing the magnitude over the frequency range and the second is the phase against frequency (http://en.wikipedia.org/wiki/Bode_plot)
If you see the literature, on complex numbers (http://en.wikipedia.org/wiki/Complex_number), the polar form describes how you can convert Real +/- imaginary to magnitude and phase. Notice that, in general, the magnitude is expressed in log scale and special care is necessary to allow you to use the functions. Fortunately for you, System Identification allow you to use "linear" scale in the conversion. You define this on the "FRF format".
Also, notice that the SI Estimate FRF function is only used when you have the time-domain data (input and output over time) and the other functions in the frequency domain Model Estimation palette are used to convert bode responses into a polynomial in the S-domain or Z-domain.
Please let me know if you still can't configure the functions.
Barp - Control and Simulation Group - LabVIEW R&D - National Instruments

Calendar Application System Configuration Assistant failed

Hi
I'm a newbit to OCS and have been trying to installl OCS 10.1.2 on Red Hat ES4 on a HP DL385 box - 6 GB and got stuck at the Calendar Application System Configuration Assistant part.
Retried it several times, both in Basic or Advanced installations and also, checked the possibility of NO EXEC issue for AMD64 box. The logs are:
Starting to execute configuration assistants
Launched configuration assistant 'Calendar Application System Configuration Assistant'
Tool type is: Recommended.
The command being spawned is: '/mnt/ocs_home/10.1.2/ocs_1/apps/jdk/bin/java -classpath /mnt/ocs_home/10.1.2/ocs_1/apps/jlib/ldapjclnt10.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/jlib/ojmisc.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/lib/xmlparserv2.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/lib/emSDK.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/lib/emOCS.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/jlib/emOCSSDK.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/ocas/oem/log4j.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/jlib/emConfigInstall.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/ocal/jlib/ocal_clnt.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/lib/servlet.jar:/mnt/ocs_home/10.1.2/ocs_1/apps/ocas/ca/ocasca.jar oracle.calendar.ocas.config.OCASCAConfigDriver enable oraclehome=/mnt/ocs_home/10.1.2/ocs_1/apps oidhost=ocs.domain.com oidport=389 oiddn=cn=orcladmin oiddnepwd=055003734da9fdcea5fee58831090ab8570e7fca930ba4907b ocasport=8010 ocheckletport=8011'
Start output from spawned process:
**WARNING** ocal.conf is already included in oracle_apache.conf.
opmnctl: stopping opmn managed processes...
opmnctl: starting opmn managed processes...
================================================================================
opmn id=ocs.domain.com:6201
0 of 1 processes started.
ias-instance id=ocsapps.ocs.domain.com
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ias-component/process-type/process-set:
HTTP_Server/HTTP_Server/HTTP_Server
Error
--> Process (pid=30582)
failed to start a managed process after the maximum retry limit
Log:
/mnt/ocs_home/10.1.2/ocs_1/apps/opmn/logs/HTTP_Server~1
There was a problem starting Oracle HTTP Server.
**ERROR** java.io.IOException: /mnt/ocs_home/10.1.2/ocs_1/apps/opmn/bin/opmnctl: returned -52
oracle.calendar.ocas.config.OCASCAException: java.io.IOException: /mnt/ocs_home/10.1.2/ocs_1/apps/opmn/bin/opmnctl: returned -52
     at oracle.calendar.ocas.config.OCASCAUtil.restartOHS(OCASCAUtil.java:347)
     at oracle.calendar.ocas.config.OCASCAConfigDriver.run(OCASCAConfigDriver.java:150)
     at oracle.calendar.ocas.config.OCASCAConfigDriver.main(OCASCAConfigDriver.java:18)
Caused by: java.io.IOException: /mnt/ocs_home/10.1.2/ocs_1/apps/opmn/bin/opmnctl: returned -52
     at oracle.calendar.ocas.config.OCASCAUtil.runExternalProgram(OCASCAUtil.java:377)
     at oracle.calendar.ocas.config.OCASCAUtil.restartOHS(OCASCAUtil.java:342)
     ... 2 more
usage: OCASCAConfig
[{-s,--standalone}]
[{-w,--oiddnpwd} oid_dn_password]
[{-e,--oiddnepwd} oid_dn_encrypted_password]
[{-d,--oiddn} oid_dn]
[{-h,--oidhost} oid_host_name]
[{-p,--oidport} oid_port_number]
[{-o,--oraclehome} oracle_home]
[{-i,--enable}]
[{-m,--oem}]
[{-z,--reset}]
[{-r,--ocasport} ocas_port_number]
[{-t,--ocheckletport} ochecklet_port_number]
[{-c,--calservhost} calendar_server_host_name]
[{-g,--calservport} calendar_server_engine_port_number]
[{-n,--calservnode} calendar_server_master_nodeid]
End output from spawned process.
From oraInstall xxx.err log, we can see the last lines:
PassEnv ORACLE_HOME
PassEnv LD_LIBRARY_PATH
PassEnv NLS_LANG
PassEnv TNS_ADMIN
include "/mnt/ocs_home/10.1.2/ocs_1/infra/Apache/Apache/conf/mod_oc4j.conf"
include "/mnt/ocs_home/10.1.2/ocs_1/infra/Apache/Apache/conf/dms.conf"
LoadModule rewrite_module libexec/mod_rewrite.so
include "/mnt/ocs_home/10.1.2/ocs_1/infra/Apache/Apache/conf/ssl.conf"
include "/mnt/ocs_home/10.1.2/ocs_1/infra/Apache/Apache/conf/mod_osso.conf"
include "/mnt/ocs_home/10.1.2/ocs_1/infra/Apache/Apache/conf/oracle_apache.conf"
Error in copying file : META-INF/
Error in copying file : META-INF/MANIFEST.MF
Any idea of what we can do for this?
Thanks for your help.
Rgds
Vicky

Hi all,
I've found a solution to this problem. So far I've been trying the installation through MSTSC by taking administrative control (through /console option). Later, I tried my luck by installing it through Net Meeting which proved to be successful.
Hope you can try the same and ged rid of the installation issues.

Technical System Identification

Guys ,
I need to add JRUN into my system lanscape , What I want to know is What will be the <i><b>Technical System Identification</b></i>, while adding the technical system using technical system wizard.
Thanks
Manish

Hi Manish,
You can give any value to identify the JRUN on the host it is running.
Thanks
Prasad

System Identification Assistant w/o NI Signal Generator

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