topic Re: Computmotor 6K Motion Controller LabView program in LabVIEW

Computmotor 6K Motion Controller LabView program

arthur51189 — Mon, 16 Aug 2010 16:37:04 GMT

Hello,

I am using the Viewpoint Compumotor 6k Motion Controller VI's. We have the motion controller plugged in through serial port. I'm looking at the Functions they offer(different VI's), but I don't see any for serial port. They have a VI 6k Communication Launcher.VI, but it looks like that's only for Ethernet connection not through Serial. Does anyone know how to create a connection with serial port.

Re: Computmotor 6K Motion Controller LabView program

nathand — Mon, 16 Aug 2010 20:26:30 GMT

I don't have access to that library, but I found the manual for it here: http://www.viewpointusa.com/6k/6K%20VI%20Motion%20User%20Manual.pdf. Section 11 indicates that they provide VIs for a serial connection - have you found those? The ethernet connection provides features that aren't possible over a serial link, so you will not be able to take full advantage of the library. I've written LabVIEW code to connect to a 6k4 using both serial and ethernet (started with serial, then moved to ethernet when I needed more control) without that library and you can make either approach work.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Mon, 16 Aug 2010 20:34:35 GMT

I've looked through the manual the serial port VI's don't offer much, the ethernet VI's offer more flexibility it has VI's to move, set distance, set velocities, but the Serial VI's don't offer it. What kind of stuff can be done over Serial, this is my first time using this type of equipment.

Re: Computmotor 6K Motion Controller LabView program

nathand — Mon, 16 Aug 2010 20:59:43 GMT

The major difference between serial and ethernet communications is the speed and ease with which you can do certain functions. For example, if you want to set a variable value on the 6k4 over ethernet, you can do that directly (by sending a packet in the right format, or through functions provided by the Com6srvr ActiveX component (which the Viewpoint library appears to use). To do it over a serial connection you have to send the command that sets a variable value, which means your computer needs to convert the value into text and send the command, then the 6k needs to parse the text and convert it back into a value. However, all basic motion control can be done over a serial connection, and for more complex behavior you'll want to write programs in the 6k language and save them on the controller. Have you looked through the 6k manual and programmers reference? Have you installed the motion planner software and controlled the 6k manually? If you don't have the manuals, you can find them on the Parker Compumotor site: http://www.parkermotion.com/products/Controllers__1745__30_32_80_567_29.html

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Mon, 16 Aug 2010 21:16:43 GMT

I have installed the motion planner software, I have the manual the one that you posted in the previous message. Right now, I'm just trying to get the track to move at a certain speed in a certain direction using LabVIEW. They offer a communication VI, the 6k Communication RS232.vi but thats it, I don't know how to set the direction and velocity to get it to move.

Re: Computmotor 6K Motion Controller LabView program

nathand — Mon, 16 Aug 2010 22:56:29 GMT

Can you get the motor to move using the motion planner, using the terminal to enter manual commands? If so, you can then duplicate this in LabVIEW. Open a VISA Serial session on the COM port to which the 6k is connected, make sure that the serial settings match (baud rate, stop bits, handshaking, parity, etc), then write text - the same commands that you entered in the motion planner - to the serial port.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Tue, 17 Aug 2010 17:05:08 GMT

What would you recommend for a beginner with Compumotor, but I'm pretty good with LabVIEW, Ethernet or Serial?

Re: Computmotor 6K Motion Controller LabView program

nathand — Tue, 17 Aug 2010 17:46:13 GMT

The first thing you should do is set up a serial connection, because you'll need it to configure the ethernet connection if you decide to go that route. Once you have the serial connection working you might decide it's all you need. You also might want to use serial if you don't want to put your 6k on your local network and you can't get a second ethernet card for your computer. The commands are the same over either connection so you can switch between them anytime. Which one is better for you depends somewhat on what you need the 6k to do.

If you're interacting a lot with the 6k and response speed isn't critical, the serial connection is fine. For repeated motions and faster response, the ethernet connection is better. Initially, I wrote programs on the 6k and ran them by sending the program name over the serial connection. Each program would print a response to the serial port that LabVIEW could read. It also provided flexibility for me to write individual 6k commands from LabVIEW when necessary, but it was slow because the 6k takes time to parse text into program names and LabVIEW needed to check the serial port to see if a program finished. A faster approach is to assign a program to run when a specific input is triggered using INSELP. That input can be a bit in a variable - a virtual input. The ethernet communication lets you send variable values directly to the 6k, so you can run a 6k program by sending the right variable value. Similarly the 6k can send an alert over the ethernet link when motion completes, which is simpler than putting a print command in every 6k program and checking for a response on the serial port.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Tue, 17 Aug 2010 18:38:50 GMT

Alright it just seems confusing, because the LabVIEW examples that come with the Compumotor. It just seems like they have me select the axis and the speed and distance and it should work, but I can't test it out until i have an Ethernet Connection.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Wed, 18 Aug 2010 17:08:04 GMT

Quick question when i use the Serial Write.vi for the write buffer when I enter the code from Motion Planner, can I enter more than 1 line of code into the Write buffer?

Re: Computmotor 6K Motion Controller LabView program

nathand — Wed, 18 Aug 2010 18:17:02 GMT

You should be using the VISA Write function to write to the serial port, and you can send multiple lines of code in the same write.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Wed, 18 Aug 2010 18:20:54 GMT

Can you check my code, I translated it word for word from Motion Planner. On Motion Planner it runs, but in LabVIEW it's not running I don't know why this is occuring?

Re: Computmotor 6K Motion Controller LabView program

nathand — Wed, 18 Aug 2010 18:33:52 GMT

You need to send a newline after every command. You can include the newline in the string constant, just go to the end of the string and hit "Enter". You may want to combine all the string constants into one (or two - one for setup, one for motion) and write all the command together.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Mon, 30 Aug 2010 18:54:29 GMT

I can get the tracks to move and when I move the tracks in a positive distance (away from the motor) after it is done moving it will go back to HOME. When I move it in a negative distance(towards the motor) the tracks will always move back to the limit and then go back to HOME, although I'm not telling it to go to the limit. Is there a way I can fix this issue? Thank You.

I have attached my code

Re: Computmotor 6K Motion Controller LabView program

nathand — Mon, 30 Aug 2010 19:47:11 GMT

Are you asking about the homing operation at the end of your program? HOM1 runs in the negative direction. If you move past the home sensor in the negative direction and then execute HOM1, it will continue running in the negative direction until it hits the limit, then reverse direction until it finds the home sensor. That's how homing works. In many applications, you home the motor at the beginning to establish the zero position. To move directly back to that home position at the end of the program, you execute an absolute move to 0.

Two minor comments: 1) you don't need a blank line after every command, you just need to put each command on a separate line, with one blank line at the end, and 2) why are you setting homing parameters at the end of the program after you start the homing operation?

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Mon, 30 Aug 2010 19:57:29 GMT

I'm not sure how to set the homing parameters so after my track moves, it will move back to the home position?

Re: Computmotor 6K Motion Controller LabView program

nathand — Mon, 30 Aug 2010 20:13:46 GMT

Am I correctly understanding that after every sequence of moves, you want it to return to the home position by the most direct route? You never tell the system what the home position is in the first place, so it can't know which direction it needs to move to find that home position. If you don't like watching the motor run to one end of travel and then back to find the home position, you could try homing to an end-of-travel limit instead, so you always run the same direction to find the home position.

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Mon, 30 Aug 2010 21:30:24 GMT

I'm sorry but I don't quite understand. After the movement of the track I want it to go back to the home position no matter which way it travels(whether in the positive or negative direction).

Re: Computmotor 6K Motion Controller LabView program

nathand — Mon, 30 Aug 2010 22:46:06 GMT

@arthur51189 wrote:

I'm sorry but I don't quite understand. After the movement of the track I want it to go back to the home position no matter which way it travels(whether in the positive or negative direction).

Isn't that what it's doing now, except with a detour through the end-of-travel limit when it has already passed the home sensor in the negative direction? I think you may be misunderstanding the HOM command. It doesn't go to the home position, it finds the home position, as shown in this (sloppy) picture. You're telling it to find the home position starting in the negative direction and that's what it's doing. It sounds like what you want it to do is to move towards the home in the positive direction if that would be shorter. In order for that to happen, the system would need to know where the home sensor is before it started homing, and if it knew that, why would you run the home procedure at all?

Re: Computmotor 6K Motion Controller LabView program

arthur51189 — Tue, 31 Aug 2010 17:59:17 GMT

But how come after the track moves, it goes back to the original home position