Motor control by serial port

So now I decided to move to a little hardware
I have been controlling the speed and direction of a DC motor by passing a combination of ASCII values and HEX values.For eg:- P20 will give me some speed P50 will give me another.M1/0 will rotate the motor in both the directions.S will give me counts which has been converted to the respective RPM.
So I have no issues here. But now I have to implement a PID controller with it.
That means Set Point will be decided by user(That is me) and Process Variable(PV) will I think be the feedback from the output of RPM.And, I think output of PID will be given as HEX to VISA.I don't know.Am I correct over here?
How to implement the motor control with the PID block?
Can anyone guide me in the right direction?
Attachments:
Basic Serial Write and Read1.vi ‏23 KB

Hi Sunny,
the output of the PID is a number used to set an actuator. In your case you have to send that number to your motor control board, which expects strings (not any kind of HEX)! As you already gave examples of the expected strings you would use a FormatIntoString function to form the proper commands.
VISA also only uses strings as in-/output, you have to create them anyway!
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

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I have previously developed an automated video microscope application in Labview. It worked great. My setup was: NI PXI system with 1409 image board, 7344 motion controller, 7764 breakout box, stepper motors, motor drivers, and tables. Now, a customer is requiring that we use a specific brand of drivers that encompass a motion controller and are daisy-chained together. Communication will take place from a serial port, thereby bypassing the 7344. My question is: will I have to can my entire previous Labview motion/data acquisition program b/c I won't be using the 7344 controller? Or, will it be easy to specify in the program to commmunicate via the serial port rather than the card? Would this setup take place in MAX, or in the LabView applicatio
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Hello,
I am working on a project which requires the operator to be able to control the motor's rpm and whether it is on and off from a labview interface. The motor is a Kollmorgen servomotor(AKM42E-ANDNC-00) which is connected to a danaher S20360-VTS controller. The controller is connect to the computer through the serial port.
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Thanks
Solved!
Go to Solution.
Attachments:
msm20001_rev_C.pdf ‏2222 KB
akm_deis.pdf ‏1913 KB
BasicReadWrite.JPG ‏126 KB

John, thanksm for the response. I keep getting the feed back in the attached image below. I am in contact with Kollmorgen now and will update you when I get a response to my problem.
Attachments:
BasicReadWrite.JPG ‏126 KB

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If Windows can't find the serial port, then LabVIEW isn't going to find it, and it's irrelevant what you've coded. You should go into the Windows Device Manager to see what it tells you about the device. Does it even show up in the list of devices? Does it have a driver loaded? If it doesn't show up in Device Manager, try plugging the card into another PCI slot. Does the card show up if you plug it into another computer? Perhaps the card is bad.

Time out function in VISA configure serial port vi

I have some doubts regarding the time out functionality of "VISA configure serial port vi":
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1. A read will return when the first of the following is satisfied:
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A31 Serial port only works on dock..?

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Hi freaky-namuh, welcome to the forum
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Using serial port to communicate with servo motor drive

I wish to use Labview 7.1 to control a brushless servo motor with encoder (from MCG) and digital drive (from AMC) via the serial port. The application simply involves progressively loading the shaft on the motor in 180 degree increments, and reading the torque. Is this possible? If so, how complicated is this approach? Thanks!

Communicating with your AMC drive via LabVIEW is no problem. There is an example in the Example Finder (Help >> Find Examples . . ) called Basic Serial Write and Read.vi which will show how to send and receive serial commands. You will have to find out what serial commands your drive responds to by looking at the AMC drive user manual. Certainly there are commands to position your servo motor at various increments and at various speeds.
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Serial port control -- what's this code snippet?

Hi, all.
I've just become active working with LabView, version 6.0i. And this because of a program which "suddenly" stopped working, with no changes made by anyone that I can see (yeah, likely story, right?).
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Attachments:
VI_diagram.jpg ‏17 KB

I suspect someone did change it, but they just don't realize they did.
THe code snippet is an example of some very bad LV code! What you suspect is happeneing is indeed true. LV uses a data dependacy paradigm that says code execution order is dependent on data availablility. Data availability is determined by ythe rule that the output of a node or sub-VI is not available until the object completes.
In you snipet, the only node that has to complete before the read bytes at port and the write to port VI is the the constant port number constant. That means that LV can execute either the write or the check bytes at port VI's first. This is determined at LV compile time. If for some reason LV decideds to compile in the write before the check bytes at port, the
n the I/O may work as intended, BUT NOT POROGRAMMED!
For a quick fix, put the contant port number and the write VI in a single frame sequence structure. This way the read from the constant and wire operation must comlplete before the seq completes, therby forcing the read stuff to wait.
I hope this help,
Ben
Ben Rayner
Certified LabVIEW Developer
www.DSAutomation.com
Ben Rayner
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Serial port control

hello
is it possible to control, using labview, the inputs and the outputs of a serial port as they were simple digital on/off channel?
for example in order to use them to turn on/off a relay or to read the state of a switch
I've searched among the labview examples but they show only complex communication to an hardware using strings...
thankyou in advance
paolo
Solved!
Go to Solution.

You can control the handshaking lines Request to Send (RTS) and DTE Ready (DTR). You can read the handshaking lines DCE Ready (DSR) and Clear to Send (CTS) as digital inputs.
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Message Edited by Ravens Fan on 09-10-2009 04:27 PM
Attachments:
Example_VI_BD.png ‏2 KB

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Motor control by serial port

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