topic Re: Unidrive SP PDO Communication in LabVIEW

Unidrive SP PDO Communication

enorrav — Mon, 29 Jun 2009 14:59:42 GMT

Hello,

I am currently working on controlling through Labview and CanOpen a testrig that includes a Control Techniques Drive, so it can act as a vehicle emulator. So far I've been able to do it through SDO, however I would like to do it through PDO. If I configure manually PDO1, I can read values stored in the drive without a problem, however when it comes to write I don't get any error but I also don't get any response. As I go through the CT CanOpen manual, there seems to be a gap in how to do the mapping for the different PDOs, and how to access the specific menu and parameter. I've also been unable to do the mappings through SDO for the other PDOs. I'm attaching what I've been working on so far, and I hope you can point me in the right direction. Probably I'm not making myself clear, so if you need any other information let me know.

Enrico

Re: Unidrive SP PDO Communication

gt3000 — Tue, 21 Jul 2009 09:38:08 GMT

Hello Enrico,

Which version of LabVIEW are you using?

What hardware instrument are you using to communicate with your drive?

I have looked at the attached VIs, however it seems that certain SubVI's are missing from the ZIP file for the PDO Write. As you are receiving no error when running the VI, then your programming must be in the right direction. As there is a SubVI missing, I am not entirely sure what the data packets look like that you are trying to write to the drive. It may be that the data packet contains data, but is not enabling the drive to do anything. Frames for PDO contain a Control bit. If this is set to zero, it could mean that the remain bits of data are being ignored. Can you check whether this is the issue?

At this point, I would also like to point out that a specific CAN section exists on the forums that is monitored by enthusiasts and users of that field. In the future, you may wish to consider using that section for a noticebly quicker reply on the topic.

Regards,

Re: Unidrive SP PDO Communication

enorrav — Thu, 23 Jul 2009 12:14:35 GMT

Hey George,

Thanks for your reply. I'm currently using LabVIEW version 8.5.

To communicate with the drive I'm using CANopen, NI-PCI-CAN Software version 1.1.1

I have attached now the SubVI's that were missing, I apologize for that. As for the control bit, there is a parameter in the drive that controls the motor 6.43, called 'control word enable' that sets that specific bit to 1. I've done it before the PDO configuration, but I still have the same issue, unless it has to be set at another point.

To make things a bit easier, I'm attaching a slight modified version of the Analogue Output VI, that's found in the CANopen examples folder. In the drive, there are 4 PDOs, each with 4 TxPDO and 4 RxPDO channels. The first PDO can be configured directly from the drive, and that's how I've been able to read parameteres. However, when it comes to write, that's when the problem comes. With this VI, the first RxPDO channel is configured to set the speed of the motor (directly configured in the drive), but I'm not getting any response.

Thanks again,

Enrico

Re: Unidrive SP PDO Communication

RavensFan — Thu, 23 Jul 2009 14:11:58 GMT

Enrico,

What is the address number of your drive? I haven't used CAN with CT drives before, but I have done serial communication using their ANSI protocol, so I don't know if CAN uses the slave address also. I had started with a Commander SE and setup my LabVIEW drivers and got them working just fine. When we got a Unidrive SP, the same drivers worked, except I had one problem to work around. If I remember correctly, I couldn't get a response when my drive was set to the default value of 1. But when I changed it to another address (11 in my case), I was able to get a response. I have no idea whether my issue was a programming problem or a quirk of the drive. I suspect a quirk of the drive, but once I got it working, I didn't go any deeper in trying to figure it out.

This may or may not help you. But it was such an odd thing and really non-intuitive thing, that maybe you are having the same issue.

Re: Unidrive SP PDO Communication

enorrav — Thu, 23 Jul 2009 15:00:26 GMT

RF,

Thanks for sharing that! Unfortunately that's not the case here. I'm guessing that you're talking about the Node Address (at least in my case or how I know it). The drive addresses are set to 60 and 61. Probably it's a matter of how I'm configuring the PDO, or something that I'm doing wrong when I'm mapping them..

Cheers,

Enrico

Re: Unidrive SP PDO Communication

RavensFan — Thu, 23 Jul 2009 15:13:15 GMT

In my manual, the parameter I was talking about is called serial address at menu 11.23. I am using the RS-485 serial communication with ANSI protocol. The terminology for CAN is probably different and may be under its own set of menu parameters.

I was hoping your problem would be as simple but impossible to figure out as mine was.

Good luck with solving it. And please report back with the solution once you are able to figure it out.

Message Edited by Ravens Fan on 07-23-2009 11:13 AM

Re: Unidrive SP PDO Communication

Mustanghipo65 — Tue, 16 Aug 2011 20:18:14 GMT

I'm working on controlling a unidrive sp through labview 10. I can use the software supplied from control techniques to read and set parameters on the drive using a serial 485 connection, both ANSI and MODBUS work. I am having a hard time understanding the protocol for either ansi or modbus so I can build labview drivers. I also had to set my drive to address 11 when using their ansi protocol.

Would it be possible for you to post some of your driver vi's?

Re: Unidrive SP PDO Communication

RavensFan — Tue, 16 Aug 2011 20:47:15 GMT

Are you asking Enorav or me for drivers?

I came across the same situation with the Unidrive SP where I had to make the address 11 to get responses. With the default address of 1, I just never seemed to get replies back from the drive. (Though I don't remember any problems with the Quantum 3 drives that use the dame protocol.)

Re: Unidrive SP PDO Communication

Mustanghipo65 — Tue, 16 Aug 2011 21:11:46 GMT

I was asking you Ravens. I thought it would fit inside of this thread so I didn't want to create another. I've tried using the MODBUS drivers with the drive set up for RTU but always received a timeout error.

Ok, while I was replying I decided to try the MODBUS drivers and had sucess in reading a register. Forgive me but this is both a new instrument and new protocol for me. I've only dealt with GPIB and basic RS232 scpi commands in the past.

It could be a great help to have a peek at those drivers though so I can have an idea of where to continue.

Thanks!

Re: Unidrive SP PDO Communication

RavensFan — Tue, 16 Aug 2011 21:18:01 GMT

Sure. Let me dig those up, zip them up, and post them to the thread.

Re: Unidrive SP PDO Communication

RavensFan — Tue, 16 Aug 2011 21:50:15 GMT

Take a look at the attached zip file. I had a project where I was primarily controlling a 150 HP AC motor with a Unidrive SP. I stripped out some auxiliary stuff, but most of the code is still here.

I like to centralize the motor controller communications, so I do that in a single loop. I also set it up as an action engine so I can initialize things like the com port and the drive address and keep those values stored.

One thing I added was a side dialog that pops up so that I can read or write to any parameter besides the handful I'm looking during normal operation. It just injects its commands into the communication.

(Note: This is saved in LV 2009.)

Re: Unidrive SP PDO Communication

Mustanghipo65 — Wed, 17 Aug 2011 13:53:31 GMT

I like how the way you poll the drive for status updates by using recurring queues. I think that project will help me out greatly.

I'm using this unidrive to control a linear actuator from Exlar, which is nothing more than a strong servo. Thanks for the help!

Re: Unidrive SP PDO Communication

RavensFan — Wed, 17 Aug 2011 14:58:38 GMT

We use some Exlar actuators also. But we've used some Control Techniques MD-434 servo drives to control them. For my more advanced test stand, that drive has a program module add-on. I wrote a program on that which would take some parameters and actually issue and execute a move command. So it is the real brains of the system. But I used modbus parameters to get the motion parameters from the PC to the drive and also return some status parameters such as current position, velocity, etc. If I remember correctly, I used the same queue mechanism where I re-enqueue the repetitive commands such as polling the modbus status parameters. I like this method because once I set up the recurring stuff, I don't have to do any extra work to keep them running. The one-time commands get put into the queue and get executed soon enough. And by not doing an actual polling, I'm not flooding the communications with multiple copies of the same data requests in the event the serial communication gets slowed down or lost for some reason like a disconnected cabled.

Re: Unidrive SP PDO Communication

Mustanghipo65 — Wed, 17 Aug 2011 15:39:09 GMT

This is our first project that is using actuators/servos so we went with what the applications engineer said would be best, which was the unidrive SP. We're testing the hold strength of an item, it must be able to hold piano wire with almost 1,000 lbs tension. What i'm planning on is commanding the unidrive to move a few inches with a low current limit on the drive. Ramp the current limit up while monitoring the tension in the wire.

Exlar has the motor files for a unidrive so i plan on loading that using Control Tech's software, then using labview to do the rest.

Re: Unidrive SP PDO Communication

RavensFan — Wed, 17 Aug 2011 15:58:09 GMT

That sounds good. Good luck with your application.

Re: Unidrive SP PDO Communication

ElectricWraith — Fri, 02 Mar 2012 14:52:02 GMT

Sort of a related question here, I've got a Unidrive SP and I'm using the SM-CAN module. The problem I have is that the SM-CAN user guide shows command usage for Emerson's SYPT software, and of course I'm using LabVIEW.

Does anyone know of a programmer's reference that provides the lower-level CAN IDs and data word values for the drive's command set? I've looked through the user guide and Emerson's site, no luck. Called tech support three times, can't get anyone to call me back.

Help?