Motor Position Control with NI PCI-6035e?

[prphntm63]

Hello all,

I have a NI PCI-6035e card from a previous project that was used for reading analog inputs on a tensile test frame in conjunction with an exteral motion control unit. I have been tasked with combining the motion control and data acquisiton functions into one 'user friendly' program. 

The motors I wish to control are 90 volt servo motors, controlled via Advance Motion Controls model 20A14 voltage controlled motor controllers (+/- 10v input). The motors are equipped with quadrature encoders (1000 ppr). 

I noticed the 6035e has two analog outputs and two counter inputs; could it be used for position control?

Thanks

[FuManWho]

Hi prphntm63,

You should be able to get the encoder values using a counter input. But you may be limited to certain speeds because the card you are using can only go at 200kS/s. As for controlling the Advance Motion Controllers, that is not something that we have resources on. If you want to control using that controller, you may want to contact that company and ask for what type of control and how to control using analog outputs. The speed at which you can control is also limited in that you have software PID loops which may hinder your operations. What we recommend is a Motion controller specifically designed for this:

https://www.ni.com/en-us/support/model.pci-7342.html

[Nate.H]

Or you could use a 4 slot CompactRIO with appropriate I/O modules for your tasks. 

NI 9514 (1 module per motion axis) for the AMC servo drive control and the encoder feedback. This module also has capture and compare lines to help synchronize your analog acquisition to encoder counts.

NI 9205 32-Ch ±200 mV to ±10 V, 16-Bit, 250 kS/s Analog Input Module for the analog inputs on your test frame. 

If you were using a DAQ card before, it doesn't seem like you would have requirements for LabVIEW Real-time running on the CompactRIO.  In this case  you could use the NI 9146 4-Slot Ethernet RIO Expansion Chassis. This chassis does not require LabVIEW Real-time; only LabVIEW on your development machine. I would recommend the LabVIEW SoftMotion module for setting up moves commands with the NI 9514 modules. The lite version is all you should need and it is free. 

This system (Ethernet RIO + 9514 + 9205) can be connected to any Ethernet network or directly to the PC for programming. In my opinion it's the best fit given the info I have about your application. Of course, that's assuming you have some budget for the project.

If you are stuck with the DAQ card:

The DAQ card you have should be fine for sending the requisite +-10V analog commands to the AMC drives, assuming electrical compatibility (sinking/sourcing current). Your update rates on the AO on this card should be more than sufficient for updating position, velocity, or torque; whichever mode you run the AMC drives in. You would have to write you own code from scratch to do any sort of trajectories however. This is something which SoftMotion has built in and you can get up and running very quickly with on the NI 9514. You'd also have to setup your own syncrhonization scheme based on counter input with the quad encoder like Paolo suggested. Again, doable, but you are starting from scratch. 

You might save just as much money in time and effort as it costs to buy the new hardware recommended above for the application (my two cents). 

Best Regards,

Nate