Configuring Secondary Feedback for Position Control

Hi,
I am using PXI7340 Motion Control card with RT Controller. I am using servo motor with 35:1 gear to increase the output torque. I have two encoders (One at the motor side and the other at the load side). If I want to control motor position based on the second encoder feedback then what is the procedure for that.
Now I connected Motor side encoder as Primary feedback and load side encoder as secondary feedback. But there is no option to enter gear ratio in MAX.

Venkat wrote:
Hi,
I am using PXI7340 Motion Control card with RT Controller. I am using servo motor with 35:1 gear to increase the output torque. I have two encoders (One at the motor side and the other at the load side). If I want to control motor position based on the second encoder feedback then what is the procedure for that.
Now I connected Motor side encoder as Primary feedback and load side encoder as secondary feedback. But there is no option to enter gear ratio in MAX.
Hello Venkat,
Thank you for contacting National Instruments. It is advised to use secondary feedback in situations like yours to overcome backlash due to gearing. Backlash is the delay there can be in the motion from the motor to transfer over to the load. If the encoder connected to the load is used to close the velocity loop it can lead to a delayed response in terms of correcting the velocity. Secondary feedback is used to compensate for the backlash and is used to complete the velocity loop. Secondary feedback comes from the encoder connected to the motor. Primary feedback in this case is used to correct position errors and needs to come from an encoder connected to the load.
When using secondary feedback the Kd term of the PID is set to 0 and the Kv term is used instead. You will not need to set the gearing ratio or the encoder counts per revolution for the secondary feedback since the velocity loop is only interested in the difference in steps. More information about this procedure can be found in the NI-Motion User Manual installed on your machine with the NI-Motion drivers. You can find it under Start>>Programs>>National Instruments>>NI-Motion>>Documentation>>NI-Motion User Manual or "C:\Program Files\National Instruments\Motion\Documentation\NI-Motion User Manual.pdf". Dual Loop Feedback on page 4-30 goes into more details about this procedure. Hope this helps your out. Have a nice day!
Regards,
Nipun M.
Applications Engineer
National Instruments

Similar Messages

Analog Fedback for position control

Hi all,
Its been a long time since I have written into this discussion forum. I have a question. Till now I have been using encoder as a feedback device for position control in PCI 7342 motion controller. Now I want to know about position control using the analog input channel. I cant figure out how the controller understands the equation between input voltage and position.
Say X Volts = How many mm of movement?
With the encoder f/b the motion controller knows the encoder pulse per revolution and it keeps counting the feedback and generates motion accordingly. How is it done with analog feedback. My application involves an LVDT which give proportional analog feedback with respect to the displacement. Please help me oiut on this. Also is position compare and breakpoint feature relevant to this particular problem?

Hi Giridhar,
it's good to see you back in the forums.
I have posted a document to another thread that contains a detailed description of the analog feedback feature.
I hope that helps,
Jochen Klier
National Instruments Germany

How to configure the requirements for output control ?

Hi ,
I have some problems in configuring the requirements for output control like following :
My aim is to make a condition check when i create an inbound delivery ( VL31N) or MIGO ...., as default in the requirement check for output , a message type will be created automatically if the it satisfies the condition in the KOBEV .....KOBEV( each sub routine was defined with a message type ( V6 ) ( if sy-subrc = 0) . And then a printing program will be triggered to print the SAPscripts form in the table "tnapr" but even if i have put sy-subrc in ( KOBEV...KOBEV ) always = 0 the printing was not executed , and in this case i do not understand the reason why , If you please to help me this .
Thanks ,

Hi,
it seems that the requirement you made is not the reason why it's not printed. If you set sy-subrc to 0, this code should have no effect.
Cheers,
Stefan.

Is there and easy way for Position control using analog input?

Hi Everyone,
I would like to set one of the axis with stepper motor using analog feedback to keep the set position which is coming from the analog input.
In other words I would like the stepper to move when the analog input changes. I need it as a "background service" so the rest of the motion could be easily controlled from the NI-Motion Assistant.
Is there any easy way to do this? Even complicated is ok but the control should be done by the NI Motion card not the PC processor.
Thanks,
Andras

Hello Andras,
please use the link below to get the motion example.
http://zone.ni.com/devzone/cda/epd/p/id/353
Kind regards,
Elmar

NI pci 6251 position control

Hi
Im new to this forum and new to Labview and NI pci 6251 as well ;(
I'm using NI-PCI-6251 (DC Motor ) with Labview to control the position of a DC motor we developed the program that reads the encoder and display the position of the DC motor shaft
but the problem is that the counter 0 (cnt0) always increases whether the disc rotating clockwise or anticlockwise??!! and when the desired position is reached the controller does nothing to stop the motor ?
i don't know what is the problem or why its happening.

Hi,
I am also doing something similar.
The problem is the motor is the DC motor from Quanser. (DCMCT).
I know the encoder channel of the motor is ctr0 and when I test from "Measurement and Automation Explorer" (Labview>>Tools) I can only read the PFI8 channel.
The motor read 4096 pulses per revolution and no reading is available from PFI10. As per Quanser the motor should be about to do position control. I have seen lab tutorials for position control in internet.
I tested both the vi is mentioned above. The "Example" vi reads the motor position in terms of pulses. But when I rotate the motor in the other direction the count increment not decrement.
Also the quadratureencoderMseries vi did not read the angle position when I set the channel values.
I have attached the parameters that I set.
Can any one please check..
Thanks.
Attachments:
encoder issue.JPG ‏357 KB

Sensitive fields for dual control (vendors)

Dear Experts
I want to configure sensitive fields for dual control -Vendors. Iam unable to see the field "SWIFT".
Can any one helps, please
Regards
Ahmed Zain

Dear El Zain,
Unfortunatelly due to the SAP Standard System Design, it is not possible
to define SWIFT as sensitive field for dual control.
Table T055F was not thought to change them.
I'd suggest you to try using a BTE; please check by BERE transaction the
BTE 00001450 (Vendor master record, individual duplicate check).
'Function module SAMPLE_INTERFACE_00001450 must not be changed.
Probably by this BTE you could reach your goal.
I hope this helps.
Mauri

LIFA+servo position control

HI all, I have installed the Labview Interface for Arduino.
I just need VI s for the position control of servo motor
I have few questions regarding this
1) what is closed loop position control , can i do that with servo motor ( I am using RC servo -VS-2)
2)can i control my servo without using Arduino code , directly from m Labview
3)How to implement PID controller for position control of Servo
Thanx

If you want to control servo directly from LabVIEW, you need NI Daq card.
Your starting point should be from this link : http://zone.ni.com/devzone/cda/tut/p/id/3367
CLA 2014
CCVID 2014

Configuration guide for Action Control Matrix

Hi, Does anyone configuration guide for action control and status matrix for VMS for Equipment master, General Object creation, Master warranty creation and assignement for the object VELO.

I have seen this as well as the SAP best practices configuration guide, they do not talk about the status for CREQ. We have defined it as secondary action and executed the action but it does not create the equiment. The CS/Plant maintenance does not seem to recognise objects created from VELO. Although the documentation talks of VELO as equipment categry along with the standard equipement category EQ, we are not sure if we have to add VELO as equipment category (add how to add as well) so that the vehicle master details can be carried from VELO into equipment for warranty processing.
Thanks

Is it possible to condition a load cell signal with a 1520 SCXI and then use it as the primary analog feedback for a 735X motion control board?

My system
PXI 1052 chassis
PXI 8196 RT controller
Flexmotion 7356 motion controller
Flexmotion 7354 motion controller
6259 M series DAQ
1520 SCXI
1520 SCXI
1314 SCXI frount mounting terminal block
DSM strain gage load cells
Exlar SR Brushless PM motors
Kollmorgen servo star CD series 5 drives
My objective:
I want to measure the force on the load cells with the 1520 SCXI (i.e. excite the load cell then amplify and condition its output) then I want to use this analog (force) signal as the primary feedback for my motion control system (7356 and 7354 motion controller connected to my drives and motors).
The problem:
The motion controller boards (7356 and 7354) can be configured for force feedback control via analog feedback from a load cell. However the boards implicitly expect the load cell signal to be amplified and conditioned with and external signal conditioner rather then using an NI SCXI module. Currently I’m am reading the SCXI signals via the 6259 M seriers DAQ and consequentially have no way to route the signal into the 735X boards for force feedback control. I can use softmotion to control the motors but then I loose the fast PID update rates possible with the 735X boards.
The question:
Is it possible to condition a load cell signal with a 1520 SCXI and then use it as the primary analog feedback for a 735X motion control board?
Thanks
Patrick Aubin
Ph.D Candidate
University of Washington &
VA MedicalCenter of Excellence for
Limb Loss Prevention and Prosthetic Engineering

Hi GG,
Thank you for your feedback.
>create your own external circuitry to amplify the signal.>
True a few op-amps could amplify and filter the signal externally but the performance of such an amateur built system will never match the accuracy and functionality of the 1520 SCXI. That’s why we spent the $2500 for the professional version.
>One thing that you could do is to use a UMI with your motion controller and then wire your signal from your SCXI to the UMI.>
As I understand it the UMI is basically a break out connectivity interface for third party drives. After conditioning and amplifying the analog force signal with the SCXI module the analog signal isn’t available to wire into a UMI. To my knowledge the conditioned signal of the SCXI resides only in the PXI backplane (i.e. there is no physical access to the conditioned analog signal). Can you explain how the UMI could be help here.
Again thanks for your input GG.
Patrick

Just upgrade to 33.1.1, terrible! new tab position not configurable, no response for clicking a link, how can I have the old version? Thanks!

Just upgrade to 33.1.1, terrible! new tab position not configurable, no response for clicking a link, not going to the website by click "enter", "space" keyboard can not be the page down anymore, always die....
how can I have the old version?
Thanks!

Just to clarify, let's say you have tab 1 Google results and tab 2 something else. When you Ctrl+click a link in tab 1, it opens between tab 1 and tab 2 instead of at the end? Here's how you switch that:
(1) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful.
(2) In the search box above the list, type or paste '''tabs''' and pause while the list is filtered
(3) Double-click the '''browser.tabs.insertRelatedAfterCurrent''' preference to switch it from true to false.
You can switch back to an earlier tab and test. Success?

Configure KM folders for no feedback permission

We have the following customers needs for KM folders.
- By default, users can't feedback on a document, but they can read documents.
- Some users can read documents and make feedback (and this implies that they can read their previous feedback, that's not a problem).
- Administrators can read/write documents and write/read all feedbacks on a document.
So the problem we are facing now, is how to disable feedback by default, so that basic users can't see the link "Give feedback " on the command menu, and they can't see the feedback on the details screen.
We have configured the service permission for a folder that basic users haven't any service permission (we assume that feedback service is included) in this folders (and no permissions are inherited) or just layout service. But the fact is that the user can read the document (this is OK for us), but they can also feedback this document (that's what we don't want...).
Any idea if it is possible to configure? What's the possible solution?
Thank you very much

Hi Sergi,
"All users with read permission for an object can create feedback for this object as long as they can see the command for creating feedback on the user interface." (http://help.sap.com/saphelp_nw70/helpdata/en/3a/d609f7803111d5992f00508b6b8b11/frameset.htm)
The only restriction you can do is to restrict the feedback command to be available for certain roles, see "Roles with Visibility" in http://help.sap.com/saphelp_nw70/helpdata/en/9d/233f989a5ba64fa44ed6e0823286ee/frameset.htm
Hope it helps
Detlev

Scripting configuration for Dynamic Controls

I would like to put the configuration of Dynamic Controls (Process/Service Controls' selector values, URI, etc.) in a script to invoke from a command line. Any suggestions?

Are you want to run this script at development time before deploying or what do you want to achieve? Upcoming SP4 will offer a solution to retrieve config parameters for certain controls dynamically at runtime (and change it on the fly).
-Kai

I can not configure the secondary node for shared appl_top

when i run the perl -l txkSOHM.pl comand in the secondary node for shared appl_top. the system returns a "valid java executable not found"
i did check all my environments variables, all is exactly just like the primary node.
anybody can help me???

$ perl -l txkSOHM.pl
Absolute path of Application's Context XML file :
/u01/oracle/snb2appl/admin/SNB2_pth1ap.xml
Type of Instance [primary/secondary] :
secondary
Absolute path of 8.0.6 Shared Oracle Home :
/u03/oracle/snb2ora/8.0.6
Absolute path of iAS Shared Oracle Home :
/u03/oracle/snb2ora/iAS
Absolute path of config top :
/u03/oracle/PTH1
Oracle Application apps schema password :
pu3rt0
*** USER FEEDBACK ***
Absolute path of Application's Context XML file : /u01/oracle/snb2appl/admin/SNB2_pth1ap.xml
Type of Instance [primary/secondary] : secondary
Absolute path of Shared Oracle Home top :
Absolute path of 8.0.6 Shared Oracle Home : /u03/oracle/snb2ora/8.0.6
Absolute path of iAS Shared Oracle Home : /u03/oracle/snb2ora/iAS
Absolute path of config top : /u03/oracle/PTH1
Run AutoConfig [y/n] : y
Oracle Application apps schema password : pu3rt0
Absolute path of the log file : /u02/oracle/pth1comn/admin/log/SNB2_pth1ap/txkSetSOHM.log
Prompt for confirmation [y/n] : n
Absolute path of 8.0.6 config Home : /u03/oracle/PTH1/8.0.6
Absolute path of iAS config Home : /u03/oracle/PTH1/iAS
Application's Context file Saved as : /u01/oracle/snb2appl/admin/SNB2_pth1ap.xml.SOH
Valid java executable not found

Any Positive Feedback for 2.01 ??

I am just curious if there is any positive feedback for 2.01. I am hesitant to change so quickly after the release.....but on the same token I have many different Apple products which I never have issues with. I come here often and read a lot of complaining posts. Don;t get me wrong, I think a lot of them are done like an adult trying to solve a problem and not just a ***** session......but there are equally if not more posts that just whine and curse the apple brand.....
Anyway, I have been lucky enough to not face the cursed updates on any of my apple branded equipment. Most install without incident and all are functioning at least as well as I would hope. I am leery however of new updates so I thought I would see who might be having positive results from the 2.01 update.
Thanks

Hasn't fixed the podcast art disappearing randomly from the favorites.
Hasn't fixed the "scroll off to nowhere" when you have 50+ podcasts in your favorites, then delete one, then scroll down to the end and the highlight box just disappears off the left side, never to be found again.
What a disappointment. I wish I could get my money back on this one, what a waste of time.

Seller is bargaining for positive feedback on item sold

I purchased a screen protector for a 3DS for $1.29 with shipping. The item came in a sealed package. One of the screens is larger then it should be, so I rechecked the listing and it clearly showed the protector fitting the inside edge of the screen. So I then emailed the seller, and asked him what he would suggest as a solution. He then offered me a 30% refund. My response was "Sure! for a neutral feedback and three stars!" He then asked if he gave me a refund, or sent me a replacement, would I give him a positive review? It is only $1.29, I mean when I ordered it, I thought no big deal if it's not what I expected. But I'm not giving a positive feedback for an item that was not as described. Do I let it go, and not post any feedback. Or accept the refund/replacement and post a positive feedback....when I don't think it was positive. I have a hard time lying...even if it just withholding the truth. OR....am I making too much of the situation? This seller had 14 Neutral, and 12 Negative feedback in the past month. Their positive feedback is 98.2Thanks....PS I could not figure out how to delete the spoiler box....that's why it's there

So I then emailed the seller, and asked him what he would suggest as a solution. He then offered me a 30% refund. My response was "Sure! for a neutral feedback and three stars!" He then asked if he gave me a refund, or sent me a replacement, would I give him a positive review? Although I don't think that feedback should have been mentioned at all, I'm not sure if ebay would rule that the buyer was using feedback extortion if the conversation happened as reported. The buyer was responding to the sellers offer of a partial refund, they weren't specifically attempting to force the seller to provide: Goods or services that weren't included in the original item's description or purchase price.A return, refund, or replacement item. If the buyer said they wanted a full refund or a replacement without returning an item then that would definitely be feedback extortion. The seller did break the feedback extortion policy when they asked the buyer if they would give a positive review for a replacement or refund. The seller can't require a buyer to leave positive Feedback, specific detailed seller ratings, or revise existing Feedback in exchange for a number of things, including, but not limited to:Receiving the purchased itemIssuing a full or partial refundMonetary compensationAdditional itemsOther goods and services not included in the original listing

Configuring Secondary Feedback for Position Control

Similar Messages

Maybe you are looking for