Servomotor pci6221

Hola:
Necesito generar un tren de pulsos para controlar un servomotor pero he tenido problemas para configurar la DAQ. Considero que usando counter para generar un tren de pulsos continuos (HW Timed updates), puede convenirme; pero el "external clock type" me pide proporcionar un "clock source" y no sé como hacerlo o configurarlo. Además intente con el tren de pulsos continuos, con las phases que necesito pero, no me manda los cinco Volts sino 2.4 o 2.8 lo que no alcanza a activar el optoacoplador (no sé porque la pérdida de voltaje, ya que se supone el nivel alto debe proporcionar 5 V). El servomotor que estoy usando es el HS322HS, tiene un cable rojo (power), uno negro (negativo) y un amarillo (señal).
Alguna ayuda?????

Hola Ismael, Como comentas para controlar tu servo una de las mejores opciones es utilizar el contador. El servo esta esperando recibir un pulso cada 20ms con un ancho de pulso variando desde 1 hasta 2ms, en el cual la longitud del pulso determina la posición a la que va a llegar tu servo (puedes encontrar mas detalles de la duración del pulso en este link: http://www.seattlerobotics.org/guide/servos.html). como lo mencionas tu servo tiene 3 cables el de señal, el positivo y el negativo. La batería con la que alimentas tu servo debe de estar conectada a el positivo y negativo (debes de tener mucho cuidado con la polaridad ya que los servos son muy delicados en ese aspecto y aunque dure poco la polaridad los capacitores internos se pueden quemar muy rápido). Ahora para que hay una relación de la señal tienes que conectar la digital ground del contador también a la tierra de tu servo y el Counter Output a el cable amarillo de tu servo (en el caso de otras marcas el cable de señal puede ser blanco).
Para generar el pulso básicamente puedes hacer dos cosas si utilizas un solo contador puedes jugar con la frecuencia, dado que al servo no le importa la frecuencia sino el ancho de pulso. SI el dutycicle de tu pulso es igual con forme aumentes la frecuencia disminuye el ancho. La segunda opción es simplemente variar el ancho de pulso modificando el duty cicle.
Te anexo un ejemplo sencillo.
La caída de voltaje se puede deber a que le estés demandando mas energía de la que puede dar y por eso se genera la caída de voltaje.
Saludos
Benjamin C
Senior Systems Engineer // CLA // CLED // CTD
Attachments:
PulseServo.vi ‏28 KB

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How to configure my servomotor and third party servodrive using Servo Tune

I am trying to configure a small servomotor using a PCI 7342 motion controller and a third party servo power drive. When powered up, the motor spins at max rpm and when run, the Auto Tune function doesn't seem to have any effect other than changing the motor direction and running at -max rpm. So far as I know, the motor is set up correctly and encoder is fully functional. I have tried the default servo settings in MAX and also custom settings of what I deem to be correct for the system. The Auto Tune returns values for PID as 0, 32767, 0 respectively and changing these does have a slight effect on accelerations, but the motor has never been stabilised at 0rpm. I have changed the encoder connectio
ns (as suggected by fozzy 27/02/2002) but to no avail. I'm at a total loss.... Please Help!! Cheers.

i had the same problem with my servomotor from Thorlabs. what happens when you step the servo? does it travel until it hits the hardware limit? mine did this as it wasnt recieving any feedback from the encoder, im in the process of getting an exchange at the moment. luckily i had another servo to diagnose the prob.
dan
dsmol@cyllene*uwa*edu*au

Velocidad de servomotor arduino

hola necesito ayuda con el control de velocidad de un servomor con arduino

Hola artorres11,
Gracias por utilizar los foros de discusión de NI, te dejo algún par de links que te pueden ayudar con tu aplicación:
Este vídeo explica cómo utilizar las librerías:
Control de Servomotor con tarjeta Arduino y Labview de National Instruments
En el siguiente link puedes descargar el toolkit de Arduino para LabVIEW:
NI LabVIEW Interface for Arduino Toolkit
Espero que estos links te sean de utilidad, quedo al pendiente, ¡saludos!
David P.
National Instruments
Ingeniería de Aplicaciones
www.ni.com/soporte
David P.
National Instruments
Applications Engineer
www.ni.com/soporte

Servomotores y labview

Hola necesito ayuda con un programa
Spoiler (Resaltar para leer)
- Donde existan dos botones y que por medio se esos botones se active al servomotor,
que cada boton hara que el servo se mueva con un angulo diferente , y que claro al oprimir un boton
el otro no se pueda oprimir y visceversa .
Adjuntos:
Servo.vi ‏17 KB

Que tal wencris,
Te envío un ejemplo que te puede servir
Saludos
Juan Arguello
National Instruments México y Latinoamérica
Applications Engineer

Attuatori valvole e serrande - servomotor

salve, nell ambito di un progetto di una camera climatica mi trovo a dover pilotare serrande e valvole a tre vie in modo da poter raggiungere all interno dell ambiente le condizioni di set point (temperatura, umidità) desiderate. sulla base delle mie conoscenze, penso che dovrò avere bisogno di servomotori per attuare la loro regolazione. volevo chiedere suggerimenti su quale sia il principio di funzionamento degli attuatori, che genere di moduli di output analogico (tensione, corrente) utilizzare, se dovrò conoscere le caratteristiche delle valvole a tre vie e infine quale sia la strada da seguire per poter effettuare la loro regolazione mediante PID. è previsto l'utilizzo di piattaforma PXI.
Ringrazio anticipatamente per la collaborazione e porgo i migliori saluti.
hi, in the context of a project of a climatic chamber I find myself having to drive dampers and three-way valves so I can reach the interior environment of the conditions set point (temperature, humidity) i want. on the basis of my knowledge, I think I'll need to implement the servo adjustment. I wanted to ask for suggestions on what is the principle of operation of the actuators, what kind of analog output modules (voltage, current) I have to use, if I have to know the characteristics of three-way valves, and finally what is the path to follow in order to make their regulation by PID using Labview. is provided for the use of the PXI platform.
Thank you in advance for your cooperation and I extend best wishes.
Alessandro Pezzano
Università della Calabria
Solved!
Go to Solution.

Ciao Alessandro,
per quanto riguarda il principio di funzionamento degli attuatori non penso che troverai qualcuno che ti possa rispondere su questo forum, ti consiglio quindi di capire il funzionamento, scegliere quello più adatto per la tua applicazione e poi magari sul forum ti possiamo aiutare con degli esempi o ti possiamo suggerire dei moduli per controllare quello specifico servo motore.
Nel frattempo di posso allegare alcuni link di esempi per progetti PID:
PID Motor Control
https://decibel.ni.com/content/docs/DOC-16983
Reference Example: Multi-channel PID Control with Operator Interface on CompactRIO
https://decibel.ni.com/content/docs/DOC-4134
PID Control Reference Example for LabVIEW FPGA
http://www.ni.com/example/30814/en/
Multiple Servo Axis PID Reference Example for LabVIEW FPGA
http://www.ni.com/example/31049/en/
Spero che questo ti sia utile,
Buona giornata,
Valerio

Motorcontrol, Motorsteuerung, Festo Servomotor

Hallo,
ich möchte erstmals mit Labview einen Servomotor "MTR-DCI" der Firma Festo am liebsten über die RS232 Schnittstelle steuern.
Zur Steuerung gehört
die Drahzahlgeschwindigkeit
Drehrichtung
6 1/4 Umdrehungen
der Motor hat einen eingebauten Controller und eine RS232 Schnittstelle
kann mir jemand weiterhelfen.
vielen dank für die Antworten
Solved!
Go to Solution.

Hallo,
die Thematik ist eigentlich nicht sonderlich Motion-Control-spezifisch. Letztlich geht es darum, mit einem Gerät, hier eben einem Motion Controller, über die serielle Schnittstelle zu kommunizieren. Auf tiefster Ebene funktioniert das über die VISA-API. Beispiele zur seriellen Kommunikation werden mit LabVIEW installiert und sollten eine gute Starthilfe darstellen. Im einfachsten Fall gibt es für das anzusteuernde Gerät bereits einen Instrumententreiber für LabVIEW, so dass die Low-Level Kommunikation durch einen einfahc zu bedienenden Satz VIs abstrahiert ist.
NI bietet zwar für über 6000 Geräte Instrumententreiber zum Download, allerdings handelt es sich dabei größtenteils um Treiber für klassische Messgeräte. Für die MTR-DCI-Steuerung ist dort leider kein Treiber vorhanden, eine Rückfrage bei Festo könnte sich aber dennoch lohnen.
Falls es keinen Instrumententreiber gibt, muss direkt mit den VISA-Funktionen (schreiben/lesen) gearbeitet werden. Die zu sendenden Kommandos und die entsprechenden Antworten des Geräts sollten in der Dokumentation der MTR-DCI-Steuerung zu entnehmen sein. Grundsätzlich empfiehlt es sich, bei der eigenen Entwicklung eines Instrumententreibers, auf bewährte Programmiermethoden und Strukturen zurückzugreifen, um eine Wiederverwendbarkeit zu gewährleisten. Tipps dazu finden sich auf der oben verlinkten Webseite unter dem Thema "Learn to build instrument drivers".
Viel Erfolg.
Jochen Klier
National Instruments

Control a servomotor without NI motion

Hi everyone,
I'm currently working for six months as a trainee in a company to complete my formation and become an engineer.
My goal is to develop a program to control a tensile testing machine. After 4 months here, the program is already finished in LabVIEW 8.2.
It uses several subVIs from the NI-Motion package (version 7.2) in order to control the servomotor Parvex RS440G that moves the horizontal bar: Clear Power Up Status, Enable axes, Set I/O Port Direction, Motion Error Handler, Read Positon, Board ID, etc.
It works perfectly!
What's the problem, then? Well, the company is moving to LabVIEW 2010, and they're not buying the NI-Motion package, so my beautiful program will not work anymore.
The easy solution is to leave the 8.2 version in the computer that controls the machine, but I'd like to know if I can't do anything else.
First question: will the NI-Motion 7.2 subVIs work in LabVIEW 2010?
If they don't, do you think it's possible to reproduce these subVIs "manually" in LabVIEW 2010 in the seven weeks I have left? I really doubt it.
Thank you for your time, I'd really appreciate some good advices.
P.S.: sorry about my English!

Hi,
Another possibility is to download for free NI-Motion driver 8.3 which is compatible with LabVIEW 2010.
http://joule.ni.com/nidu/cds/view/p/id/2597/lang/fr
Sincerely
David S.| Certified LabVIEW Associate Developer
National Instruments France
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Servomotor

hola buenos dias, quiero controlar un servomotor con alguna de estas tragetas NI ELVIS , NI 9219, 9403, 9263 con cual de estas tragetas puede controlar un servo de 5 volts de una manera facil y sencilla . gracias

Hola ps3fer,
El siguiente ejemplo te puede servir, recuerda modificar el target y los módulos en el proyecto:
Servo motor (RC) control using LabVIEW:
https://decibel.ni.com/content/docs/DOC-22207
Saludos.
David P.
National Instruments
Applications Engineer
www.ni.com/soporte

DAQmx non-cumulative buffered edge counting (like the PMT TTL problem) with PCI6221 in C program environment

I have a PCI-6221. I am programming in C/C++ and DAQmx. My application is much like the previous thread counting the number of asynchronous TTL pulses from a PMT in some user specified time interval. The time interval is typically around 1 msec and the signal rates are around 1-10 kHz. So I expect to count 0 to 10 pulses per timebin. In traditional DAQ this was called Non-cumulative buffered edge counting.
To get a clock at about 1kHz, I first create an "analogue in" task that samples at 1kHz. The only thing I use this task for is to route its sample clock to the gate of the counter. This defines my time interval as 1 msec.
I then create the counter task. I am using count edges. So I think counter0 gate = PFI9 and source = PFI8.
DAQmxCreateCICountEdgesChan(*taskHandle,chan,"",edge,initialCount,countDirection);
DAQmxCfgSampClkTiming(*taskHandle,clockSource,rate,DAQmx_Val_Rising,DAQmx_Val_ContSamps,samplesPerChan);
where clockSource="/Dev1/ai/SampleClock"
I apply my signal to PFI8.
After starting the task, I read an array of values with
DAQmxReadCounterU32(taskHandle,samplesToRead,10.0,data,samplesToRead,read,NULL);
I expect the array data to have values ranging from 0-10 for PMT input with an average rate of about 10 kHz. The trouble is that the array data does not seem to make sense. I get constantly increasing values. For very low input frequency, it just increments by one per array member.
More troublesome, when I hold PFI8 at ground, so that I expect zero pulses to be counted at the source for each edge at the gate that occur 1 per msec, I get a timeout error. I really must be able to count zero events per bin.
Am I doing something obviously wrong?

Hello,
The behavior of non-cumulative event counting is equivalent to period measurement. Additionally, the timeouts when no edges occur on your event counting terminal are the result of duplicate count prevention. In DAQ 7.4, the default behavior of duplicate count behavior should take care of this for you, but if you cannot upgrade to DAQ 7.4, I'd do a search of the discussion forums for "duplicate count prevention". There are a number of previous posts about this attribute, including this one.
If you aren't using the second counter on your device, you should be able to use the Period Measurement 2 Counter High Frequency measurement method to get your desired values. The "Measurement Time" attribute in this case would be the "sample clock" (1 kHz in your example). Then just raed the data raw to get counts rather than scaled.
If you'd like to do it using the AI timing engine. Configure a 1 counter period measurement task, use "clockSource" as your input terminal and use your PMT TTL pulses as the "Counter Timebase Source". Then read the data raw, since the scaling will not be appropriate for your needs.
I hope this helps!
gus....

Don't know how to set current limit for servomotors in MID

My application is to control a servo motor. I�m using PXI-7350, driving a motor (Pittman GM8712F434) with MID-7654. The motor is connected to mechanic parts and mechanic parts are connected to a potentiometer as a feedback. Now, according to the spec of the motor, it said reference voltage 19.1V, inductance 5.4 mH, peak current 1.76 A. So, I set dip switch of MID to 0.85 A for continuous current, 1.70 A for peak current and standard inductance. The motor didn�t move and fault LED lighted. Then I set both continuous and peak current to around 1.7A. The motor still didn�t move and fault LED still lighted. I kept increasing the current until the current hit 3A. It started moving slowly but fault LED still lighted. Final
ly I set the peak current to 3.5A, the motor ran normally. Come to the questions.
1. Is the peak current in the spec same as peak current limit in MID? How to determine peak current limit? Because I�m afraid that my little motor is going to burn out.
2. How to set the continuous current; is it suppose to be half of peak current?
3. If +10/-10V command voltage(torque limit) gets map to peak current (let say 1.7 A), will +5/-5V be mapped to 0.85? And what happen after 2.7 sec if I set continuous current to 0.85A? Will +5/-5V be mapped to half of 0.85?
4. How does �2.7 sec� thing works? When I set peak and continuous current to 3.5A and 1.7A, after 2.7 sec motor should run slower or even stop (in my case), but it went nut like it ran at maximum current.
I set Kp 20 and others zero, everything else is same as default. Thank you, I appreciate your answer.

infoiupui,
There are several DIP switches on the front of the MID 7654 that can be toggled to vary the continuous and peak current values for the MID. There is a small panel that can be removed from the lower left corner of the MID. You can look in the manual for the 7654, linked below, to determine the particular settings that you should use to achieve given continuous and peak current values.
MID-7654/7652 Servo Power Motor Drive User Guide
http://digital.ni.com/manuals.nsf/webAdvsearch/E382785B7D67553E86256A5D0072BBE1?OpenDocument&vid=niwc&node=132100_US
Take a look at pages 10 through 13 of this document for information on how to modify those DIP switches to achieve current values that will work with the motor that you are using.
I am not clear on w
hat you are referring to when you referred to 2.7 seconds. Could you clarify that for me?
I hope that helps! Let me know if you have any additional questions on this issue.
Regards,
Scott R.
Applications Engineer
National Instruments

About time resolution on PCI6221 card

Hi all,
I am going to purchase a PCI-6221 DAQ card. I read the specification and it turns out that the sampling rate is 250kS/s, which means it can produce or collect 250000 sample per second, correct? So does it mean the time resolution is 1/250000=4000ns? I am reading the datasheet and it shows that the timing resolution is 50ns. So my question is what does that 50ns mean? If I have an externel signal with frequency is higher than 250kHz, does it mean PCI-6221 is not be able to capture that signal correctly?

Looking at the specs, this MB Pro comes under late 2007 spec, but checking supported resolutions, it more than covers native resolutions for both main display and the NEC simultaneously.
Can anyone shed some light on this, or have I got this wrong? Is it down to DVI or could I use VGA with an adaptor - would this give me better resolution?
Cheers.

Can Labview control equipment such as servomotors?

Hi!
I am new to LabVIEW products and have just started my PhD a month ago. My project involves recording EMG signals from muscles. So i need to be able to control 2 motors (from a software...maybe labview?)that would move a limb and while the limb is moving, i will be recording the EMG signals via electrodes. I have already bought a DAQCard-6062E with NI-DAQ Software to link up my electrodes to my laptop. But now i need to figure out if it is possible to use LabVIEW itself to link these 2 parameters:- control of motors and recording of resulting EMG signals from motion.
Thanks.
Message Edited by Support on 10-05-2007 09:55 AM

Hello,
NI's motion controllers provide several features for the synchronisation of measurements and moves and they integrate very well into LabVIEW. Unfortunately you have decided to do these measurements with your laptop and this is not a good platform for motion control and synchronized measurements in general as there is no RTSI bus available for PCMCIA-based components apart from the fact that there are no PCMCIA-based motion controllers available.
If you could use a desktop PC with PCI components your task would be pretty simple but with the given setup your only chance would be to use an external motion controller and use the step signal or an encoder signal of this controller as an external scan clock for your 6062
Best regards,
Jochen Klier
National Instruments Germany

Data acquisition/control is reduced when reading in frequency

I am using a 6024E interface to operate a PID loop that keeps the RPM stable of a servomotor but having problems when attempting to read frequency at the same time from a flow-meter.
Basically the operation of the system is as follows;-
User sets an RPM demand, say 5000RPM, an analog signal is sent out to the motor controller which equates to this RPM (obtained operating system open loop) and motor runs up to this value after a brief delay. The feedback from the motor is from its shaft encoder which gives 1000 PPR, after signal conditioning in hardware this signal is applied to the gate of timer 0 and after scaling applied to the PID loop. This configuration is now quite stable and responds quite well to the operator demands. However the first problem was noticed when the RPM demand was taken to zero and an attempt to halt the program was made. There was a delay in shutting down that was roughly equiv to the time out value which was set on the DAQMX read Vi.
Things became much worse when a further loop was added to read a flowmeters frequency output (approx 50 to 300Hz max, counter 1) that varied with the servo motors RPM demand. This additional routine has almost stopped the whole program initially starting as it appears that counter channel 1 is waiting for an input before letting the rest of the program run. I have tried using the trigger functions to control the counters, i.e disable them until the servo motor reaches say 1000RPM but keep getting errors to say that mode is not supported. I guess that I could probably call the whole routine for the frequency measument only when required by using a case statement, but this seems to be a bit 'rough', configuring channels, start, read, stop etc every time the frequency needs to be read. The flow meter reading, once running needs to be fairly accurate because this will ultimatly be used in anoither closed loop to operate a stepper motor that controls the fluid flow through the flowmeter.
Sorry the above is a bit long winded and there is probably a really simple solution to controlling the counter inputs but I think I have tried most of the examples and previous suggestions that I could find on the forum. Also is there any way I could sync the analog output signal to the counter freq read signal? I found examples in the help files for this but using 'count edges' not frequency or period mode.
Thanks John
Labview Version 8.5
Labview Version 8.6
Labview Version 2013

Question re-posted in Labview forum with the Frequency read vi that is being used
Labview Version 8.5
Labview Version 8.6
Labview Version 2013

Closed Loop or Open Loop

Dear All,
I'm currently using the DAQ card PIC-6221 to control a DC servomotor with an encoder displacement feedback. I'm using the labview program with a motor amplifier to start the motor and stop it at a specific rotational displacement, where it works by stopping the motor when the encoder feedback value reaches the input desired displacement value. The final displacement of the motor before it stops always exceeds the desired value marginally. May I know for my case,am I using an open or closed loop control? Is a PID controller a MUST for closed loop control? Is my DAQ card capable of desigining a PID controller? If so may I know how?
Also, my project requires me to toggle between the current and voltage mode control. May I know if that is possible to carry out digitally using the Labview Program as my current motor amplifier requires me to push a switch manually to toggle between Voltage and Current mode. Finally, I hope my last question is not out of this world but is it possible to use 2 amplifiers(drivers) for a single motor such that there's a chance to use both the current and voltage modes of control?
Really looking forward to the replys of you kind souls out there! Thanks!
Regards,
Oompa

Oompa,
to learn more about the general concepts of motion control, please visit this link.
In general I widely agree with JB's suggestions. I'll just add some more comments to your questions.
If you need closed loop control depends on what you try to accomplish. If you just want to generate a certain torque (current mode) that is proportional to the output voltage of your control device, you may not need to run a closed loop system. A similar statement is true for the voltage mode.
Closed loop control is especially important if you need to control the position, or if you need to run a special trajectory profile (position/velocity/torque over time)
Maybe it's possible to control the current/voltage mode of your drive with a digital signal. You will have to find out in the manual or check with the vendor.
Using two drives with a single motor doesn't seem to be recommendable. If you want to do something like that, you will need to switch the power signals with relays between the two drives, but as you are working with inductive loads this might become quite tricky and there is a risk to burn both, the motor and the drives...
Regards,
Jochen Klier
National Instruments

How to measure current and voltage and rpm with daq device

i am measuring current and voltage and am wondering should i use shunt resistors or current sensors hall effect sensors. i have a pci 6221 and a scc-68 breakout box. what specifications or size should the shunt resistor/current sensor be or should i use another device to measure the currrent and voltage. do i need any other safety device between the resistors, current sensors and the scc-68 breakout box when measuring the current and voltage. will the daq card pci 6221 pick up a signal from the resistor. what terminals should the wires from the resistors and current sensors be connected to in the scc-68. i am using a proximity switch to measure rpm of a motor. should the proximity switch be 2 or 3wire connection. should it have an analog or digital connection and is a power supply required to power the proximity switch and should it have an npn or pnp connection

hello,
i was going to use a 20amp 50mv, or a 20amp 100mv current shunt and connect wires directly into the AI input terminals of the scc-68 from the current shunt would these be suitable. would current shunts such as these be suitable to use http://uk.farnell.com/elc/sh10020/shunt-sh10020-20a-100mv-1-class/dp/1319576 or http://uk.farnell.com/datel/3020-01098-0/shunt-50mv-20a/dp/1339338
is it ok to use either a current shunt or should a hall effect sensor be used such as this http://ie.farnell.com/honeywell-s-c/csla2cd/sensor-hall-effect/dp/1082269 . which of them would be more accurate or are both of them fairly accurate.
when i am measuring voltage can i connect two resistors between the positive and negative of the wires going to the battery and connect two wires from either side of the resistor directly into the analog inputs of the scc-68 and measure the 12-15 volts directly would the pci6221 and scc-68 be able to measure the voltage drop across the resistor.
i wanted to measure rpm also does it matter whether the proximity switch has 2 or 3 wires and should it have an analog or digital/frequency output for cponnecting to the scc-68

Servomotor pci6221

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