Vi to drive R/C servo

I plan on using a high precision R/C servo to control control surface deflections for an experiment that will be run in one of our wind tunnels. I would like to drive the servo with Labview and am curious if anyone has any experience doing it. I need to generate a pulse modulated signal to control the servo.

You will probably get more responses to this question if you post it under the Motion category.
There is a motion control tutorial in Developer Zone you should check out titled "Determining the correct drive for your servo motor". http://zone.ni.com
There is also a KnowledgeBase entry titled "Specification Issues When Using the Servo NuDrive with a Specific Motor" that is worth checking out. You can search KnowledgeBase at http://www.ni.com/support

Similar Messages

Connecting Yaskawa Sigma II Servo Drive (SGDH) to PCI-7344 and UMI-7774

Hi,
I have NI PCI-7344 and UMI-7774 and i want to
Connect the UMI-7774 to Yaskawa Sigma II Servo Drive (SGDH) , the servo motor drive is connected to the servo motor with original Yaskawa cables.
1.  do you know if National instruments provide special cables to connect the UMI-7774 to the Yaskawa Sigma II Servo Drive (SGDH) ?
     i know there is special cable to connect this servo drive to the NI PCI-7390
     http://zone.ni.com/devzone/cda/tut/p/id/5908
(you can find in this link that this cable exist: 50 Pin cable for connecting MCA-7790Y to Yaskawa Sigma II Servo Amplifier)
     but this is not the case here, i need to connect the Servo Drive to the UMI-7774..
2. Where can i find a tutorial on how to configure the PCI-7344 in MAX to send simple commands to the Servo Drive
      i.e. to run the servo motor from position A to position B (10,000 encoder pulses)
i'll be gratefull for any help
Regards
Moti

Hi MotiM,
We do not have a cable that will let you directly connect the UMI-7774 to a Yaskawa Drive. We do sell cables that will have the Dsub connector to match the UMI-7774 with pigtails to wire to the drive. If you take a look at the product page for the UMI-7774 you can see the different cables listed under the accessories.
To perform a simple move in Measurement and Automation (MAX) is very simple. In MAX under NI-Motion select your PCI-7344. Under this section select the settings option (by default it will be called Default 7340 settings). Select the Servo radio button. Initialize your controller. Then you can select Interactive and 1-D Interactive and command your motor from there. I have attached an image with the important areas highlighted for you.
Message Edited by Adam_H on 09-19-2008 03:41 PM
Adam H
National Instruments
Applications Engineer
Attachments:
MAX.jpg ‏93 KB

Torque mode servo drive.

Hello I come here to verify some information.
I've an DAQ card which outputs a analog voltage +/- 10 [V]. The DAQ is connected to a servo drive. The servo generates a pulse width modulation signal and passes it to the motor. Now the voltage represents a certain torque which the motor should deliver.
The manual states that I can put the servo into current ("torque") mode. My question is what do I need to understand about the term "torque mode". Is it correct then that I just can send my signal (which represents a certain torque) over a resistor to the servo then?

Current=torque. The analog signal is proportional to the current that the drive will put out. I am not sure why you need a resistor. If the DAQ is +/-10VDC, and the drive is +/-10VDC, then you should be able to connect them directly. 10VDC=max current that the drive is set up for.

I want to use the Function Generator VI to send command signals through the NI 7344 motion controller. This will be a closed loop servo valve system. I want to be able to change from say a square wave to a sine wave on the fly. Idea's?

I am going to run tests that require an actuator to move using various types of arbitrary waveforms such as sine or square. The NI 7344 is hooked to the UMI that is going through a driver for a servo valve. The loop is analog and it is closed. I have played with some of the examples but can't get it to work. I have used the function generator VI to generate a signal but I think I am using the wrong input VI to the motion control board. When I use what I have it moves the servo and then stops. It doesn't continually generate the signal.
I would love to use the controls on the function generator vi to control frequency and amplitude ect. Any help or pointer would be helpful. Thank you in advance.

Hello,
I'm not clear on exactly how you want to use the generated data but I'm assuming they will be used as your target points.
There's a built-in example for motion called 'One-Axis Contour Move.vi'. This example demonstrates how to provide your target points as 1-D array. All you need to do is to replace the input array with the output of the function generator. In order to have it run continuously, use a while loop. You can further program your application so that it'll change the waveform on the fly by monitoring the user interface but this might be little little tricky as you will need to reset the move and load the new generated points while keeping track of your current position.
I hope this helps. Let me know if you have further questions regarding this
application.
Best regards,
Yusuf C.
Applications Engineering
National Instruments

Connecting NI-7358 and UMI-7774 to a sinusoidal commutation driver

Hello,
I'm using NI-7358 PCI motion control card and UMI-7774 to drive a brushless servo motor driver Advanced Motion Controls S16A8 External Sine Commutation driver. (It doesn't have isolated ground.)
It's inhibit input like below:
                                ^ 5V
                                 |
                                 >
                                < 10K
                                 |
(-INH / EN ) o----------------> to control logic
GND              o----------------
                                              |
UMI's inhibit output is connected the drivers inhibit input directly. But there is something wrong with this connection. Control card's inhibit output always stays energized so that driver always stays disabled. (When inhibit input is connected to ground directly it's working properly)
When inhibit signal is active (axis is killed) UMI's inhibit output is 3.5V.
When inhibit is deactived (axis is started) UMI's inhibit output is 4.9V.
NI7358 inhibit is configured active low
UMI 7774 is configured active low
Driver is configured as active low.
I tried both open collector and totem pole configurations of NI7358. Results were the same.
Could you help me please.
Kind regards...
PS: AMC driver's manual: http://www.a-m-c.com/download/datasheet/s16a8.pdf

Hello,
>>1. What do the lights on the UMI indicate when you change the Inhibit Output Settings in MAX (enabled or disabled)? When you change these settings make sure you initialize the drive after changes.
inhibit disabled from MAX ------>   UMI Disable led is always on
inhibit enabled from MAX ------->   UMI Disable led is on when axis is killed
                                                 UMI Disable led is off when axis is started
>>2. If you have the drive inhibit line connected directly from the UMI to the drive what are the results of changing these inhibit output settings? Are there any LEDs on the drive to indicate if it is enabled or not?
When the inhibit line is connected to drive directly, it's enable led is always red (it means disable) since it configured as active low. When I change its polarity to active high it always indicates green (enabled) whether the UMI's inhibit line is low or high.
When inhibit signal is active (axis is killed) UMI's inhibit output is 3.5V. When inhibit is deactived (axis is started) UMI's inhibit output is 4.9V.
>>3. What happens if you reverse the polarity in MAX and/or the UMI?
Drive is always green or red according to drive's inhibit polarity.

Connecting Parker's AR-08AE driver to PCI 7350 card

I have an Aries AR-08AE servo driver (by Parker) to drive a brushless servo motor (also by Parker). I have been unsuccessful at connecting the motor to the PCI 7350 card through a 68-pin screw terminal. I cannot get the motor to respond when i use the "interactive" section of MAX.
I have no prior experience with motion control. Can someone please explain to me the proper wiring configuration between these two devices. I've attached the pin diagram for the Drive I/O Connector of the Aries driver.
Thanks in advance
John Gillingham
Attachments:
AR-08AE_DriveIOConnector.pdf ‏481 KB

Hi John,
I don't have access to your drive or motor so I couldn't test this configuration, but it should work something like this to drive your servo motor. Make sure you double check our Manual for the 7350 Controller against the manual for the drive.
7350 Controller   Drive
Pin 6                   Pin 1
Pin 3                   Pin 21
Pin 32                Pin 14
Pin 31                Pin 15
Encoders:
Pin 36               Pin 3
Pin 3               Pin 4
Pin 37               Pin 5
Pin 3               Pin 6
Pin 38               Pin 7
Pin 3               Pin 8
That should be all you need to get it to work. Also make sure you check the Inhibit polarity from MAX to be sure Inhibt is not enabled when you are trying to do a move.
S. Arves S.
National Instruments
Applications Engineer

Labview to input acceleration profiles on velocity drives

AMC recently suggested the use of labview to control a motor and servo I was interested in. I currently have AMC's B30A40 PWM servo drive, MBL3416E2 Brushless servo motor, and PS50A-LV power supply. I am emailing to ask if I could use all these in conjunction with labview to input an acceleration profile and achieve my goals of motion control. My curve profile will need to accellerate from 0, hit peak velocity, then deccellerate back to 0.
And if so, does AMC have any example VI's as well as wiring schematics? Also, I have the USB-6009 DAQ available. Any help with this issue would be great.

Hi Danstrong,
You can definitely use LabVIEW to control servo motors as you described. I would suggest taking a look at the NI USB-6009 User Guide and Specifications, which can be found here:
http://digital.ni.com/manuals.nsf/websearch/CE26701AA052E1F0862579AD0053BE19
Specifically, take a look at the Analog Output section (page 21), which describes the output voltage and current of the USB-6009. You will want to make sure this device will output the appropriate voltage/current required by your motor to operate.
Also, here’s an article that describes various DAQ functions in LabVIEW, which you could use to control your motor. Specifically take a look at section 8, which describes using LabVIEW to write analog output signals.
http://www.ni.com/white-paper/2835/en/#toc8
Additionally, National Instruments offers Motion Control Software. The LabVIEW NI SoftMotion Module offers higher-level graphical development tools to control your motor. More information on these products can be found here:
http://sine.ni.com/nips/cds/view/p/lang/en/nid/14234
Regards,
Lindsey W. | Applications Engineer | National Instruments

Pwm - Sonar/Servo Area Detection

Hello,
In the process of developing an area detection, a stopping point has been hit. The included code is simply for pwm on a MyDAQ. The pulse wave is to drive a RC servo. Really where the dead stop has occured is that the pulse wave only drives the servo between 0 degrees and 90 degrees. I'm not sure why this is the case. The vi starts by using a shift register to move between 1 and 10. This is a back and forth process. This process is intended to develope the part of the pulse wave between 1ms and 2ms, which according to most data sheets will take care of moving the servo back and forth between 0 and 180 degrees. It is my understanding that the complete wave cycle must be around 20 ms. There is a for loop for adding 10 to the shift register, and determining if this is greater than the iteration of the for loop. If this evaluates as true the case structure builds and array for 180 degrees, and if false developes an array for 0 degress. In all the waveform to my understanding follows the necessary process for devloping a PWM which would drive a servo. Again, it only goes from 0 to 90 degrees.
Thanks for any helpful hints
Attachments:
Sonar_PWM Area Detection.vi ‏80 KB

My recommendation would be to look over the below community example on how to output a PWM signal on your myDAQ hardware. The specific application is different, but the DAQ calls are the same. Rather than building a custom array and then continually writing the waveform, you should be able to set the duty cycle directly using the DAQmx Timing VIs and property nodes.
https://decibel.ni.com/content/docs/DOC-23438
Karl G.
Applications Engineer
ni.com/support

NI-9516 Drive Command

Hi,
I'd like to use a NI-9516 (Servo Module) through the SCAN interface, to drive my "servo driver".
My "servo driver" have three control inputs :
- A position control input (square stepper signal)
- A Velocity control input (+ / - 10 Volts)
- A Torque control input (+ / - 10 Volts)
I want to drive my "Servo Driver" in "Velocity" mode with NI-9516 module.
I saw in the documentation that only a torque control was possible (Drive Command output), I'm right ?
Is there a solution to control my "servo drive" in "Velocity" mode with NI-9516 module in SCAN mode ?
Thanks for your answer.
Christophe B.
Solved!
Go to Solution.

Hi Christophe,
With the 9516, you will only be able to control the drive in torque or velocity mode; you need the 9512 to control the drive in position mode.
Can you tell me what is the advantage of a control in "couple mode" over a "speed mode"?
I'm not sure what you mean by 'couple mode'. If you mean torque mode, then there isn't really a difference between running the drive in torque mode or velocity mode. The only thing that changes is the location of the velocity loop. You may find that one of the two options makes tuning the system easier (I prefer torque mode but I know other people who have found velocity mode easier to tune). You also may find that using the drive in velocity mode will allow you to better utilize the peak torque of the drive.
Is the block "Drive Command" only serves to condition/scale the analog output signal?
You are correct. For most drives I've seen, the default values work fine. However, I have also seen some drives that only take a 0-10V drive command. In this case, you would change the negative torque limit to be 0.
Is the (position loop) functionality is to simply get measurement and commands, and generate analog output (drive command), according to the "position loop" scheme?
You are correct. The position loop gets a position setpoint from SoftMotion and feedback from an encoder and then uses a PID control loop to get a drive command signal. That drive command signal will either be a torque command (if the drive is in torque mode) or a velocity command (if the drive is in velocity mode).
Thanks,
Paul B.
Motion Control R&D

Encoder polarity

Hello,
I'm using a MXI controller card to a PXI 7344 motion controller and a NI MID-7654 servo drive.
The servo works, but the encoder counts in the negative direction. I can changed "line A" to active high and the encoder counts positive, but the motor moves too far and I get following errors. I have tried different combinations of lineA/LineB/index active high/low, but the current setting is the only way that I have found to avoid the errors. Any suggestions?
Message Edited by vt92 on 03-12-2009 03:46 PM
"There is a God shaped vacuum in the heart of every man which cannot be filled by any created thing, but only by God, the Creator, made known through Jesus." - Blaise Pascal
Attachments:
encoder.PNG ‏43 KB

I agree with AK2DM. There is no standard that defines which is phase A and B of the encoder, so you typically have a 50% chance to find the correct setting right from the start. In older NI-Motion versions you would have had to change the wiring, but in newer versions you just need to adjust the settings in MAX.
If your motor still doesn't move correctly, this sounds like a tuning issue. Please visit the Understanding Servo Tune tutorial for more information about this topic.
Regards,
Jochen Klier
National Instruments

What 7D autofocus settings for birding / to photograph flying birds ?

Hi
What kind of autofous settings do you prefer to photograph flying birds with Canon EOS 7D ?
There are plenty of options there...what do you use ? What do you recommend to try ?
What kind of metering modes do you suggest for flying birds ? Center-Weighted ?, Partial Metering Mode ?, Spot Metering Mode ? or Evaluative Mode ?

I do not have my camera with me right now, yet I have a copy of the settings I had found long ago that I use as a basis for sports/bird photography. Hopefully this will help guide you in the right direction! It is a great starting point, but I encourage you to change one thing at a time and shoot to see how it affects the outcome and/or process!
Picture Style - Standard (but sharpness upped to 4)
C.Fn III: Autofocus Drive
1 - AI Servo tracking Sensitivity: Set to -1
2 - AI Servo 1st/2nd img priority - Set to 0 - AF priority/Tracking Priority
3 - AI Servo Tracking Method - Set to 0 - Main Focus point priority (that way the camera focuses on what you want, not what it wants)
4 - Lens Drive when AF impossible - Set to 0
5 - AF Microadjustment - Set to 0 (Most people have said this is ineffective. Even the manual says it needs to be done on location where you are shooting to do any good.)
6 - AF area select mode - I have single point w/expansion selected and single point. Been shooting mostly on single point w/expansion for sports.
7 - AF Manual pt. selection pattern - Set to 1 (Continuous)
8 - VF display illumination - set to 1 (Enable)
9 - Display all AF points - Set to 0
10 - Focus Display in AI Servo/MF - Set to 0
11 - AF-assist beam firing - set to 2 (Enable to external flash only)
12 - Orientation linked AF point - Set to 0
13 - Mirror lockup - Set to 0 (Disable)
C.FN IV: Operations/Others
Shutter button is set to Meter only
AF-ON button is turned OFF (too easy to hit accidentally)
AE lock button (*) is set for metering and AF Start

MAX kills axis

Hi,
I'm working on a school project for my thesis.
This project has stood still for over 6 years and is now continued by me.
Specifications:
- UMI
- PCI-7344
- Three Drives: TLD134F
- Three servo engines: SER....3S
- Firmware of the PCI-7344 is updated
Situation:
It's goal is to read the depth of cordinates in a XY-plain with a laser.
So there are three portal robots (Berger Lahr). Two portal robots move in the X-axis
One portal robot moves in Y-axis and has the laser attached to it.
Here comes the issue:
All portal robots work perfectly with Drive 1(connected to Axis 1) in the twin line control tool and in MAX (automated movement).
Once I try to make a portal robot work with Drive 2(connected to Axis 2) in MAX it kills the axis. In the twin line control tool I can manual move the portal robot. When I try to connect Drive 1, that works perfectly, with Axis 2 it reacts the same as Drive 2 connected with Axis 2. When the Axis 1 is connected with Drive 2 it works perfectly.
So my conclusion is that it has to do with the Axis 2. Everything is connected the same as Axis 1 and in MAX are all settings & parameters the same of Axis 1.
I've been searching for a while now and I really don't know what's wrong.
Can anybody help me?
Regards,
Mikail

Allright after some research:
Apperently the power for one axis necessary, on the UMI, is 5v max?
But the power supply in the electric cabinet(that berger lahr has delivered) is 24V for one axis
Should I add a resistance?
Situation in the electric cabinet:
A converted DC signal of 24V is connected to each drive.
From each drive to each respective axis.
But i don't know how much that voltage is?
Only one, the one that worked 6 years ago, is certainly not 24V (i've checked that with an universal meter and it was constantly 0.45V)
The other one just kept rising from 1 to 6V, I didn't check if it went further than that.
I've added a "scheme" to explain what I mean in my post
Attachments:
Situatie.JPG ‏26 KB

6GB RAM anyone with this setup?

Hi I have an early 2008 MBP.
Still working great.
I will be upgrading the RAM to 6GB from 4GB.
Has anyone upgraded theirs?
Does the RAM help?
I would like to hear your inputs on your setup.
Thanks!
Dipp

Hi Biodoc,
At the simplest, you could set the 7344 to operate in position or
velocity mode, if either of those is what you are trying to do, and
connect the analog output of the 7344 to the Command +/- of the drive
to run it like that, and connect the encoder outputs from the drive to
your controller accordingly. You will want to be careful not to connect
digital outputs from the drive to the controller, because the
controller can only handle 0-5V signals, but the controller will send
out 0-12 or 0-24V signals on those lines. Similarly, a 5V TTL signal
output from the 7344 via digital out to the drive may not register
because the drive expects 12-24V signals.
To help you further, it would help to get a better idea of what are you
trying to accomplish with the drive - control a servo using step and
direction, control using absolute positioning or velocity, or some
other method? Do you have any limit or home switches you are also
trying to connect?
Regards,
Vijay S.
National Instruments

Axis Disabled LED on UMI not Lit when disabling the Axis in MAX

Hello,
I'm using MAX to disabling Axis, Axis2, Axis3 of PCI-7344 and UMI7774,
I click save and "initilize" in MAX, i get message "OK".
The DISABLED LED of the Axis1 - Axis4 on the e UMI is not Lit,
i also notice that in MAX under Motion IO setting, the "inhibit input setting" is grayed.
i found a post of someone with same problem, he said that he 'enabled the inhibit input in MAX' and this solved the problem.
but its grayed un my MAX...
This is his post: UMI-7774 / PCI 7340 Disable Indicator Error
http://forums.ni.com/ni/board/message?board.id=240&message.id=5760&query.id=13536#M5760
But, there is also a knowledge base: "Inhibit Input Setting in MAX is Grayed Out"
http://digital.ni.com/public.nsf/allkb/01CE29B6175371118625714C0058C2B1
in this article, its ok that it is grayed cause its only used on pci7390...
But he has same hardware as i have... So, what is going here? how can i solve this?
When i'm looking in MAX on "1D interactive" i found that when i change the state of the Limits, its shown in max
"limit switch is active" "home switch is active"...
The control connector of Axis 1 (the axis i want to work with) is working fine i think..
for example: i test the voltage on pin 3 : 5V as should be.
the UMI connected to V and C 24VDC power supply, and the Viso,Ciso connected to different power supply.
(V and Viso LED of the UMI is On , ALL other LED is Off.....)
Any help is appriciated, i want to start from begining to troubleshoot what is wrong,
i think that before any wiring is made to the Axis control and feedback connector, the Axis that is disabled in MAX should have their DISABLED Led on the UMI on.
The pci-7344 connected to the UMI-7774 with SHC68-C68-S cable.
Thanks
Moti

Hello Michelle,
Thank for your reply.
actually i didnt do anything about tuning the servo because i read here in some post in the forum,
that when i set the servo to "P-command" i dont need to set something in the servo tune in MAX...
its probably not right...
Thank you for the links about the servo tune, i'll read and test it now.
I'm using Yaskawa servo motor with Sigma FSP servo drive, i put it in Position command mode.
please see the attached image with all the setting in MAX (if you open it in microsoft paint, you can scroll it down like word document..)
Hereunder more details about the problem:
1. when i'm using 1d interactive for simple move, the servo is run well, no problems,
      the count is ok, the servo stop exactly in the position he should be.
     This is true as long as the velocity is 1125rpm or under.
     The problem: when i set it to 1150rpm and click start, the servo is rotate and imidiatelly stop, its looks like the servo got cough,
     there is some delay of some miliseconds and it rotate again for few steps and stops.
     when i'm looking at 1D interactive- Misc. Plot, i see the velocity is 1/4 of the velocity i set to this move.
     if i set the velocity to 1000rpm, the servo is run at 250rpm...
      its something with ratio of 1/4.. So, i think that its encoder problem, or something wrong in the setting
      cause i set the "Stepper steps per revolution" = 8192 and "Stepper counts per revolution" = 8192 also,
      where i know that it should be :
       "Stepper steps per revolution" = 2048 and "Stepper counts per revolution" = 8192
       But if i set it like this, the servo is never go to the position i command him.
2. About the "Servo -On" signal, attached the servo drive wiring, the servo on is a signal that anable the drive,
    when the servo on is activated the led screen on the servo drive displays "run" and the shaft has holding torque.
    The problem here is not with the servo on signal, that works fine, as you can see in the attached image, the servo on is activated using a relay, so for now i'm activatig it manually, when i want to start move in MAX, i turn on the "servo on" signal,
the servo drive is on, display the "run" and ready to recieve the "step","dir" commands, and it works.
The problem that the Axis/Enable signal in the UMI7774 need to activate the relay that activate this "Servo on" signal,
and currently the Axis/Enable signal is always ON, even when i press "Kill" in MAX the Enable signal is still ON and never changes to off,
that is why i can activate the "servo on" signal using the Enable signal on the axis.
I'm using: Widows XP proffesional sp3, LabVIEW 8.6 , MAX 4.5, NI-Motion 7.7, Motion assist 2.3,
PCI -7344, UMI-7774, Yaskawa servo motor and Servo Drive Sigma FSP,
here is the link to it :
http://www.yaskawa.com/site/products.nsf/products/Servo%20Amplifiers~fspsigma.html?openDocument&seq=...
Thanks for your reply,
MotiM
Message Edited by MotiM on 12-19-2008 02:00 AM
Attachments:
MaxSetting.JPG ‏579 KB
ServoDrive.JPG ‏105 KB

Analog i/O Speedy-33

Hi,
I have a Speedy-33 that seems to run fine with the example vis, so far.
As I want to use it for things like position controllers for example, I need analog inputs and outputs.
As far as I read, the connectors on the board are AC-coupled, so that I cannot use them. I have read about expansion connectors on the board, but the information about this, that I found on the ni-site is controvers about it.
Then I have read about a robotics daughterboard.
Is this useful for the task?
Does anybody have experience?
Regards
Norman Butzek

The SPEEDY-33 does provide for the use of a separate motor control module, but this module does not provide any additional analog I/O than that supplied on the SPEEDY-33. There are several VIs that allow interaction with the motor control module and include RC Speed Control, Motor Drive Control, and Servo Drive Control.

Vi to drive R/C servo

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