Control & Simulation Loop failed to compile

Dear Forum Members,
I have a problem with a Control & Simulation Loop program (attached) that just doesn't compile & run. I believe that the problem is associated with the 'Feedback Node' at the bottom of this Control & Simulation Frame since if this is taken out the program will run ok.
Can anyone please advise me if this 'Feedback Node' is incorrectly used or in violation of anything. I have tried various ways to overcome the problem i.e. initialising it at the start but nothing works. The error message that I received just says "VI failed to compile".
Appreciate any help with this.

Hello bunnykins,
The Feedback node really isn't a supported function in control design and simulation. The behavior you're reporting, and the work around are both documented in the know issues of the module here:
201449
Return
A Feedback Node on a Simulation Diagram causes the VI to fail to compile
The Feedback Node does not make sense semantically within a Simulation Diagram, due to the fact that most ODE Solvers will execute the diagram multiple times per iteration and may need to reject steps and try again, filling the Feedback Node with bad data.
Workaround: Use the Memory block from the Simulation Utility palette. If a delay of greater than 1 is desired you can chain multiple memory blocks in sequence.
Reported Version: 8.5
Resolved Version: N/A
Added: 07/31/2010
Applications Engineer
National Instruments
CLD Certified

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Attachments:
Control_n_Sim_Test.PNG ‏9 KB

Hi Siamak,
Thanks for your reply mate.
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Attachments:
tone info extraction.png ‏134 KB

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hi!
I want to simulate asynchronous generater. but I cant run my VI. It failed to compile. I have read some reason in this forum but I cant fix It. who can help me!
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MPDB_2.zip ‏1951 KB

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Hi Willy,
I am sorry, I can not upload the VI some of the content is confidential. I have attached a larger picture of the section were the change in volume and time is calculated, dV and dt. Also I have marked the two memory functions used. Hopefully this can help.
My parameters:
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- Relative tolerance      1e-8
- Absolute tolerance     1e-7
- Minimum step size 0,0005
- Maximum step size 0,01
- Initial step size         0,01
- Auto discrete time      On
- Decimation                 0
- Synz loop to timing source off
Attachments:
06-05-2014 21-20-00.png ‏52 KB

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Hi, another LabView newbie here.
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fuzzy in simulation loop.JPG ‏52 KB

Hi Sankhadip,
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How to control DC motor in a simulation loop??

Hi,
I am Xiaofei, a beginner of LV. We plan to use feedback control on 2 DC motors using Simulation loop. Now the question is: i am not quite sure if the simulation loop is only a virtual simulation of the system, or it can be used to control the real system. We will use 2 encoders to detect the actual postion of the motor shafts, and the decoding code works well in a while loop, as the attached VI. But we don't know how to make it work in a simulation loop. Whenever we put it in a simulation loop and click "run", there's no response no matter what we do on the system. So if you know, could you tell me if the simulation loop is suitable for our application and what we can do to run the encoders in it? Thanks a million!!
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Hi Xiaofei,
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Hello,
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Resetting Integrator in Control and Simulation Loop

Hello,
I am trying to run a real-time simulation in Labview 14. I have prepared front panel controls and data flow such that I can reset the simulation to some preset initialization values upon clicking a button. However, I am not able to figure out how to reset the integrator in the control and simulation loop. Even after reinitialization of all the values, the integrators will overwrite the initialization values with whatever they were holding. Please help me find a way out.
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Please share what code you have so that we can see what you've tried and understand exactly what you're trying to do.

How to reset indicators in a control design and simulation loop before each run?

Hi,
I am new to Labview. I have tried using property node to reset indicators before each run. But since it is in a simulation loop, it gets resetted many times. I am primarily interested in resetting only before each run.
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Hi Divya,
This KnowledgeBase article describes 2 methods for resetting your Front Panel programmatically:
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ERROR:Simulator:861 - Failed to link the design

hi
i'm a very new student user of xilinx 14.2 design tool who just used it 2 weeks.
this week i should do "Simulate Behavioral Model" but i can't....
just i saw below messages.. and i don't know what is the matter.
Started : "Simulate Behavioral Model".
Determining files marked for global include in the design... Running fuse... Command Line: fuse -intstyle ise -incremental -lib unisims_ver -lib unimacro_ver -lib xilinxcorelib_ver -o {E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/full_adder1_TB_isim_beh.exe} -prj {E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/full_adder1_TB_beh.prj} work.full_adder1_TB work.glbl {} Running: C:\Xilinx\14.2\ISE_DS\ISE\bin\nt\unwrapped\fuse.exe -intstyle ise -incremental -lib unisims_ver -lib unimacro_ver -lib xilinxcorelib_ver -o E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/full_adder1_TB_isim_beh.exe -prj E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/full_adder1_TB_beh.prj work.full_adder1_TB work.glbl ISim P.28xd (signature 0x1048c146) Number of CPUs detected in this system: 2 Turning on mult-threading, number of parallel sub-compilation jobs: 4 Determining compilation order of HDL files Analyzing Verilog file "E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/half_adder1.v" into library work Analyzing Verilog file "E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/full_adder1.v" into library work Analyzing Verilog file "E:/2012_fall_ISE Project/3rd week/1bit full adder/full_adder1/full_adder1_TB.v" into library work Analyzing Verilog file "C:/Xilinx/14.2/ISE_DS/ISE//verilog/src/glbl.v" into library work Starting static elaboration Completed static elaboration Fuse Memory Usage: 104956 KB Fuse CPU Usage: 327 ms Compiling module half_adder Compiling module full_adder Compiling module full_adder1_TB Compiling module glbl Time Resolution for simulation is 1ps. Waiting for 3 sub-compilation(s) to finish...
ERROR:Simulator:861 - Failed to link the design
Process "Simulate Behavioral Model" failed
i've obeied the procedure in my reference but not working.
so i re thought and re did but don't know why..
in my friend's computer with OS windows 7, that works well with same source but not mine..
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my OS is windows 8 32bit enterprise k RTM ver.
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i want to know if there is anyone whose OS is windows 8 and Isim works well!!!
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please tell me :)
P.S. sorry for my poor English, i don't know english well 'cause i'm Korean,
if i could use Korean, I would say what i think and want more concretely..ㅠㅠ
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This may be the same fix that ningunos2010 provided but I got this idea from anthbs's post. I looked up what .exe files the ISim tool used, and then simply took the nt64 files and copied them over to the nt folder so that it wouldn't run the 32 bit ISim but the 64 bit one that anthbs claimed would work. At first it didn't come up with any errors it says the simulation ran successfully but it wouldn't open the actual ISim gui. In order to fix this I went to the ISimgui.exe file and unclicked run as administrator. I'm not sure if that's clicked by default or if I had changed it at some point trying to fix the issue.
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For example, I want to use Labview Control and Simulation to simulate a simple integrator (1/s). The input for the integrator is an external analog voltage (from separate electronics) coming in through the DAQmx setup and the output of the integrator is also and external analog voltage going back to the external electronics. In essence, a very simple control loop.
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Hey Cabala,
Based on your description this would be a great starting example.
https://decibel.ni.com/content/docs/DOC-11521
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Kyle Hartley
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Stopping the VI when running a infinite simulation loop

Hi,
This is my first time on this forum and for that matter, I started with Labview a few months back. I am developing a standalone application for servo motor control through USB 6211. The motor control was completed and I created a DLL which I could run through VC++. My application requires me to call this DLL or an EXE based on this VI repeatedly with direction, velocity and angle parameters and the remainder of the program depends on the finishing of this executable.
The issue was that the VI did not stop execution after the motor was turned off, I suppose due to the simulation loop. I tried using the abort execution block but was advised to avoid doing so. My next step was to move all the DAQ assistant blocks into a while loop and couple the motor ON/OFF control with the stop button. But this hasn't helped either. I am attaching the VI and the SubVI here. I went through the board but did not come across a query involving a simulation loop. Any suggestions?
Attachments:
rotate.vi ‏551 KB
Velocity_Con.vi ‏430 KB

Hi Vivek!
Thank you for contacting National Instruments. From the information you have provided here, along with the attached VIs, I would agree that it is the simulation loop that is causing the problems when stopping the VI. It looks like you are using the LabVIEW Simulation Module.
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Toolkit for feedback system? Motion; PID; Control/Simulation???

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Attachments:
feedback design1.JPG ‏25 KB
feedback system1.JPG ‏42 KB

Dear Garry,
Do you have a motion controller to interface the MID-7654 to your
computer and LabVIEW? This would be the PCI-734x or PCI-735x. If you
do, I believe that you could implement your application with LabVIEW
and NI-Motion. You could do so by using the analog feedback feature for
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Please see Chapter 13 here for more details:
NI-Motion User Manual
http://www.ni.com/pdf/manuals/371242c.pdf
Here is also a good discussion forum post on Analog feedback:
Can i use NI-7358 to implement a hybrid position force/torque control system?
http://forums.ni.com/ni/board/message?board.id=240&thread.id=2976&view=by_date_ascending&page=1
I believe that the above option would work for you, and you would not
have to use the Control Design and Simulation Module or the PID
Toolkit. Please let me know if you have any additional questions. I
haven't actually set up a system with analog feedback from a pressure
transducer before, but I believe that the above would be a very viable
option.
Best Regards,
~Nate

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