Dual loop operation using PCI7344 motion controller

I am using PCI7344 to control servo motor. Primary feedback to the controller comes from the motor encoder. Secondary feedback from the torque transducer is given to the ADC input. The motion controller is set to operate in absolute position mode with velocity, acceleration, Deceleration, target position values appropriately set. I expect the trajectory position to change automatically based on the torque feedback from the torque transducer. Is my assumption correct? I have referred the NI-Motion user manual, 7344 hardware manuals with out success. Any suggesions? Thanks in advance.

In order to perform torque control using the NI-Motion Controller, you need to use the torque sensor feedback as the primary feedback. So in the axis configuration, the ADC where your sensor is configured must be set to primary feedback. You can then use the encoder feedback to work as a secondary (velocity feedback) device. Because torque does not behave in a linear fashion like position does, you will need to have several tuning schemes and apply a gain scheduling algorithm in order to properly tune the motor to maintain torque at any point of the trajectory. You can then use the read encoder function to read the ecoder position at any torque during the movement. Your setpoint and target position in the 1-d interactive will now be in ADC bit values. The 7344 contr
oller has 12 bit ADC's which means that for a sensor with a +/- 10 volt range, you will have 20/2^12 = 4096 bit counts of movement range. This means that + 10 volts will be represented as ~ 2048 and -10 volts will be ~ -2048 and so on. Keep in mind that the ADC's on the 7344 are not calibrated so you might have a little bit of discrepancy with these numbers though youn will always get the full range of the ADC.

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How can I use one motion controller to control two robotic independently?

the help document says :
Note Configuring and clearing buffers is a processor-intensive operation on the motion controller that requires the allocation and deallocation of memory. You should configure and clear buffers only when motors are not moving and onboard programs are not running. For example, if you wish to execute three simultaneous contouring operations on axis 1, axis 2, and vector space 1 (with axes 3 and 4), you should first configure all three buffers before starting any of the operations. You can start the contour operations independently, and at different times, but should wait until all operations are complete before clearing any of the buffers.
and i tried to conduct two contouring operation on two vector space. and tried to clear or configuring buffer for one vector when another one is still moving. so that i can start or end the movement at any time i want,and it is ok.no error. but when i tried add a buffer breakpoint output along with each vector movement. the bp doesn't work if the other vector is running . is there anyway to solve this problem.

I think you've misunderstood what the dns attribute is for. The dns attribute returns the hostname of the client accessing your website, not the hostname of the website that linked to your website.
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Inhibit output not responding in PCI7344 motion controller.

I need to use inhibit output as a enable signal for a third party drive unit. I have configured it as active high and enabled it. Inhibit output is pulled up to 5V with 270 ohm resistor. But inhibit output is not changing its state irrespective of it is being enabled or disabled? Please suggest any corrective action? Thank you.

Hello Pras,
Are you using the UMI to connect to your drive or cabling directly to the 7344?
If you are connecting directly to the 7344, then the inhibit output should sink plenty of current to pull the output low with a 270 ohm pull up resistor. Make sure the inhibit is enabled and the polarity is set appropriately for your application. Initialize the controller and check the output state. Go to the 1D Interactive section and press the "Kill" button to disable the drive. You should see the inhibit line change state.
If you are using the UMI, then there are more settings to consider. Make sure to set the inhibit output polarity switch on the UMI appropriately. Enable the inhibit output in software, set the polarity, and intialize the controller. The in
hibit output on the UMI should be inactive. If it is active (ie. in an inhibited state), then try changing the inhibit input polarity switch on the UMI. The UMI will "OR" together the per axis inhibit from the 7344, the per axis inhibit input on the UMI, and the inhibit all input on the UMI. Once the polarities are set correctly, you should be able to see the output changing state.
Regards,
Brent R.
Applications Engineer
National Instruments

How to accomplish Torque and velocity control of an axis using NI motion controller

Used torque transducer as a primary feedback. I am able to control the torque. Used Encoder feedback as secondary feedback to control velocity. But when I run the axis at 5 rpm, I observe velocity variations of more than 200 %. What is the nessasary change Should I make to control both Torque, velocity accurately?

Hello,
Here are a couple of suggestions that might help:
- Tune the PID parameters so that step response will be overdamped
- Increase the PID loop update period
- Reduce the noise on the analog signal coming in. 7350 series controllers are going to be better for this because they have a 16-bit ADC resolution versus 12-bit on the 7340 series.
Hope this helps! Let me know if you have any questions regarding this.
Best regards,
Yusuf Cavdarli
Applications Engineer
National Instruments

7344 servo motion switching between open and closed loop operation

I have a custom end-of-line test system presently using a 4-axis 7344 servo controller to perform various functional tests on small, brushed DC motors. The system is programmed in C/C++ and uses flex motion functions to control the motor during testing. Motors are coupled to external encoder feedback and third party PWM drives running in closed-loop torque mode from an analog command signal. The system uses all four motion axis channels on the 7344 board to independently and asynchronously test up to four production motors at a time.
In closed-loop mode, the system runs without issue, satisfying the battery of testing protocols executed by this system. I now have a request to add additional test functionality to the system. This testing must be run in open loop mode. Specifically, I need to use my +/- 10v analog output command to my torque drive to send different DAC output levels to the connected motor.drive while monitoring response.
I do not believe the flex motion library or 7344 controller includes functions to easily switch between open and closed loop mode without sending a new drive configuration. I am also under the impression that I cannot reconfigure one (or more) servo controller axis channels without disabling the entire drive. As my system runs each axis channel in an asynchronous manner, any requirement to shutdown all drives each time I change modes is an unworkable solution.
I am open to all ideas that will allow asynchronous operation of my 4 motor testing stations. If the only solution is to add a second 7344 controller and mechanical relays to switch the drive and motor wiring between two separately configured servo channels, so be it. I just want to explore any available avenue before I place a price tag on this new system requirement.
Bob

Jochen,
Thank you for the quick response. The 7344 board does an excellent job running my manufacturing motor assemblies through a custom end-of-line tester in closed loop mode. A portion of the performance history and test result couples the motor through a mechanical load and external shaft. The shaft is in contact with a linear encoder that closes my servo loop.
My new manufacturing requirement is to also sample/document how the small DC motor behaves in open loop operation. Your solution is exactly what I need to perform the additional functional tests on the product I am manufacturing. I see no reason why this cannot work. I was originally concerned that I would need to reinitialize the 7344 board after changing axis configuration. Initialization is a global event and impacts all four channels on the 7344 board.
Using flex_config_axis() to change axis configuration on a single channel without disturbing other potentially running axis channels will solve my concern. It will be several weeks before I can return to the manufacturing facility where the 7344-based testing machine is located. I will update this thread once I verify a successful result.
Bob

Dual loop control for positioning system.-- motion ocntrol

I am currently doing a dual loop control for a positioning system, i use the tachometer to read the velocity and the position encoder about the position of the platform.
the problem i am currently encounter is that i am not sure weather the computer have the PID toolkit, because i can not find them under the control design and simulation module. so i did a PID use the basic labview functions, related information is in the attached documents.
i am not sure about the dt part, did the labview have this kind of function like to calculate the simpling time??
do i have to install the labview real_time potion? i am right using the labview 8.5
another question is that, how i am going to let the system remember the position instead of return to 0 every time i restarted the program? otherwise is there any other way that i can command the motor to move to the target position which is initially defined?
the last question is that that is it possible for me to generate a profile regarding the current and the desired position? to set a maximum velocity and acceleration.
i do not have a motion controller, so i did not install the motion and version module.
can some one suggest me a way to do this?
Solved!
Go to Solution.

attached is the files.
Attachments:
Integral.vi ‏8 KB
Dt.vi ‏7 KB
A CLOSED-LOOP TEMPERATURE CONTROL SYSTEM.pdf ‏886 KB

PWM PID loop on 7344 motion controller

I need to control motion by PWM, with the help of 7344 motion controller.Please verify if it possible or not, and how can I do it.Please provide me(if it possible)any example of solution of this problem.

Hello,
The onboard PID circuitry can only be utilized with servos and closed loop steppers. You can write your own PID loop in software using the PWM functions and the Read Encoder Position.flx. This should work pretty well for low loop rates (since it's implemented in sw). I don't think there are any examples of it available but it should be pretty straight forward.
Regards,
Yusuf C.
Applications Engineering
National Instruments

How to control esp 301 motion controller using labview

Hi Everybody,
I am new to Labview. I am trying to connect ESP 301 motion controller from Newport to the labview and control it. But I couldn't find the drivers for it online. How can I connct it and using.
I am planning to use it with USB connection.
Could some one please help me in this regard.
Solved!
Go to Solution.

Hello Thomas
there are existing facilities:
· Two turntables XY driven by stepper motors 10 microns
· Central ESP301 command to the decks
· Central control and data acquisition: Unit PXI
I want to do the next step
· Control of stepper motors to perform scans on a large scale wafers two or four inches with a very good resolution of up to 10 .mu.m
· Programming the ESP unit 301 microstepping mode by dividing the initial step to make scans on small areas at a resolution of up to 1 .mu.m;

I want to configure the 7330 motion controller without using MAX

I am new to labview and I have a project where I have to configure the 7330 motion controller without using MAX. What do I need to do to get started doing so?
Thanks for the help!
nw2labview

Hi,
There are several VI's that are included with the motion driver for configuring your controller. They are located on the function pallete under Vision and Motion>>Ni-Motion>>Axis Configuration. Using these VI's you will be able to configure your axis. But why don't you want to use MAX? If you are new to LabVIEW I would suggest configuring and testing your motor in MAX first before you start programing. Once you have it working there you may want to look at several of the examples such as Simple One-Axis Move.vi. I hope this helps.
GG

How to use LabVIEW FPGA on Custom FPGA board other than NI products .....Also how to develop RTx DLL for a customised motion controller hardware

I'm using RTx, LabVIEW RT and LabVIEW FPGA.
The GUI is windows based. The motion control and FPGA are RTx based.
Is there any way to develop device drivers for the custom hardware in RTx. For example motion controller hardware, FPGA hardware, PCI hardware.
Is there a possibility to use custom FPGA boards to use with LabVIEW FPGA.
Please send me some links
Thanks
Bhoopathy
Take life as it comes! you may never know what's gonna happen Tommorrow

CODE WARRIOR Hello. I believe this question was answered in a previous post. Please let us know if you have any new questioins or if you need some clarification.
You are able to develop device drivers for your custom hardware using the NI Measurement Hardware Driver Development Kit.
However, it is not possible to use custom FPGA boards with LabVIEW FPGA. The FPGA boards have to be one of our R Series boards. Here are some links that should shed some light on the Measurement Hardware DDK.
Measurement Hardware Driver Development Kit Frequently Asked Questions
NI Measurement Hardware DDK (Driver Development Kit)
Please post if you have further questios.
Efosa O.
NIAE

Gain scheduling using motion controller

I have a motor controlled by motion controller.
The control gains should be different depending on the range of operation, so I want to make a gain scheduling program. I just wonder whether there is any example or idea that I can refer to. I found PID toolset document in NI website. However, it seems like I have to buy if I want to "gain scheduling.vi" in the document. If I know how the vi created, it will help me a lot. If any other method that I can look at, please let me know. Thank you.

All you have to do to perform gain scheduling in the motion controller is to select at which position you want your gains to change, and download the new gains on the fly when tha positionn is reached.I am attaching the following example vi that should help you achieve this.
Attachments:
PID_Control_Loop_Change[1].vi ‏72 KB

Motion control using MCU 28stage controller of Zeiss

Hi,
Does any one know how to control Z axis motion using MCu 28 stage controller of Zeiss, with/without LabVIEW. I am working in the windows environment. Any suggestions will be appreciated.
Thanks
Deepak

Hello Deepak,
The MCu 28 stage controller by Zeiss should have a driver that will control it. The driver will be developed and managed by Zeiss.
- If the driver is a .dll that you can make function calls to, then LabVIEW has the ability to make calls to the .dll.
- A .dll can be accessed by most programming environments (C, C++, Visual Basic... & LabVIEW).
If you do not have access to the driver for the controller, then you will need to follow up with Zeiss.
If you are wanting a significantly easier motion controller to integrate into your application, National Instruments offers a variety of Motion Controllers (www.ni.com/motion).
- If you have any specific questions regarding upgrading or making .dll calls from LabVIEW, then please contact National Instruments
at 1800 IEEE 488.

Some question about "Dual loop feedback"

http://zone.ni.com/devzone/conceptd.nsf/webmain/E7ABA6F4D569010A86256F5A005B64F3/
Switch Feedback on the Fly
Consider a heat-sink assembly application where a position sensor is the feedback device for the initial positioning along the Z axis. However, when the heat sink is pressed on to the PCB, a force sensor must be the feedback device for precise motion control in the latter part of the process. With NI motion controllers, you can switch feedback devices on the fly without reinitializing the controller. The new feedback device might require the system to have a new set of PID gains loaded immediately after the axis is reconfigured. To minimize the delay, you can configure an additional set of PID gains with the motion controllers.
anyone can give me some detailed materials about "switch Feedback on the Fly", for example, some programme,some words to explain it.
another question is that if i don't use the torque sensor, can i directly use the DAC to control the voltage to come true the torque control?
Thanks for your answer

anyone can give me more suggestion about the Dual loop feedback?
I really know little.
Hope your suggestion.
Thanks a lot

Motion controller card need to program PWM or not?

I just want to know about motion controller card (coz may be i will use it)
First, Motion controller card need to program PWM for drive DC motor or not? (If I want to control the dc motor by PWM signals!)
Second, If my motor have encoder (increment) the motion controller card can be read the position or speed directly or not?
Third, Normally motion controller card need Labview for programming or not?
Lastly, Please, could someone give me some example programming or .vi for basic closed-loop dc servo motor ?

bkk,
here are the answers you are looking for
Motion Control boards like the PCI-7344 generate a +/-10 V signal to control DC axes. As they can't provide enough power to drive a motor directly an external power amplifier like the MID-7654 or a 3rd party drive with a +/- 10 V command input is necessary. Typically these power drives generate PWM power signals for the motors.
All NI motion control boards provide inputs for quadrature encoder feedback (position and velocity).
The NI-Motion driver provides a well documented API for LabVIEW, C and other programming languages.
After installing the NI-Motion driver you will find lots of example programs for LabVIEW and C that demonstrate every aspect of the boards' functionality. NI motion controllers run the control loop in hardware so the examples will work for both, closed loop and open loop (stepper motor) applications.
I hope that helps,
Jochen Klier
National Instruments Germany

Problems with a PCI-7344 motion controller

Hi all,
I've run into a weird problem with a NI PCI-7344 motion controller, where I
have a program that provides the motion control for my program that works
reasonably well, but when I make minor changes gets motion errors. The changes
are not specifically to the motion parts, just changing a couple of globals
that provide communication with another part of the program (and another piece
of hardware). The errors I get indicate that I am trying to enable limits
switches at the wrong time in my program. I will add that I do not get any
errors when I go through the program in debug mode
Tnx,
P.W.Monroe

The portion of my program that gets the errors uses the "Flexmotion" Find Home
and Find Index routines, which are built into the 7344 controller. In the
exampes for using these VIs, they are followed by a loop that has a VI that
monitors the status of these VIs for completion, both move complete and Home or
Index Found. The globals that I mentioned are being used to terminate the loops
if an error condition occurs elsewhere, and do not cause the program to do
anything other than terminate looking at the status and then go into a wait
loop. It crashes when it goes into the loop when I substitute a different
global, which is baffling to me, as they aren't triggering something that would
result in a race condition.

Dual loop operation using PCI7344 motion controller

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