System Identification Assistant w/o NI Signal Generator

[SPV1955]

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

[JuliaO]

Hello SPV1995,

which Hardware do have exactly? Just third-party or also NI-Hardware?

Let me summarize your problem:
You have GW Instek PSW 30-108 power source and it doesn't appear in MAX, but your program is able to communicate with it.
Is this right?

Kind Regards,

Julia

[SPV1955]

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. 

[JuliaO]

Hello SPV1995,

I am not sure it the System Identification Toolkit supports Hardware that is not from NI, such as GW Instek power source. I will investigate and let you know if i find out something.

Kind Regards,

Julia

[JuliaO]

Hello SPV1995,

Which GW Instek power source do you have exactly?

Kind Regards,

Julia

[SPV1955]

Hello JuliaO

I have the PSW 30-108 Type III 0~30V 0~108A 1080W.

Regards, SPV1955

[JuliaO]

Hello SPV1955,

The System Identification Assistant uses LabVIEW SignalExpress, and SignalExpress only works with the following Hardware:

What Hardware is Supported in LabVIEW SignalExpress?
http://digital.ni.com/public.nsf/allkb/BECA073FB999797686256F340074C442

3rd Party IVI instruments are supported by SignalExpress, but yet I am not sure if the System Identification Assistant can also work with IVI or just DAQmx. If it only works with DAQmx, you can not use your Signal Generator. If it works with IVI too and you have IVI-Drivers for your device, you can use the Assistant.

I will let you know if I find out if the Assistant can also work with IVI.

Regards,
Julia

[JuliaO]

Hello SPV1955,

do you have IVI-Drivres for your power supply? If not, using it with the Assistant is no option.
As I see it at the moment, in SignalExpress IVI-Sessions you can only choose the NI-DCPower-Driver. This would mean you can't use the System Identification Assistant for your GW Instek power source.

Regards,
Julia

[SPV1955]

I have a driver for my GWInstek Device which i downloaded from the website via this link: http://www.gwinstek.com/en/product/productdetail.aspx?pid=38&mid=75&id=1294.  The problem is trying to figure out how to get labview to allow use of the driver in an IVI session.  I am going to attempt a few more things with the IVI setting to see if I can get it to work, but I believe you are correct.  Essentially the System Identification Software can be used to generate signals only with National Instruments Hardware.

[SPV1955]

I have a driver for my GWInstek Device which i downloaded from the website via this link: http://www.gwinstek.com/en/product/productdetail.aspx?pid=38&mid=75&id=1294.  The problem is trying to figure out how to get labview to allow use of the driver in an IVI session.  I am going to attempt a few more things with the IVI setting to see if I can get it to work, but I believe you are correct.  Essentially the System Identification Software can be used to generate signals only with National Instruments Hardware.