Motion Control and Motor Drives

cancel
Showing results for 
Search instead for 
Did you mean: 

PXI-7358 Brushless Motor Control, Hall Sensor Problem

I have a question regarding a system set up here to control a brushless servo motor using the National Instruments PXI-7358 motion control card along with the UMI-7774 interface board and a sinusoidal commutation amplifier.  When initializing the axis (within MAX) using the "Onboard Commutation" option, I get error 70069 indicating an invalid hall sensor state error.  I checked to see that all the sensors were working correctly (active high), and even tried rewiring the system to change the polarity of the output (active low), but got the same result when initializing the axis.

I've already had a similar system working using all the same components and a brushed DC motor, so I know all the hardware is working correctly.  Can anyone provide any insight?  Thanks.

-Ryan
0 Kudos
Message 1 of 16
(4,710 Views)
I just want to make sure that you are trying to perform commutation through the controller and not the drive.  Is that correct?  If so, then do you have the halls(from the motor) wired back to the controller?  I am not sure what outputs would have to do with commutation.
0 Kudos
Message 2 of 16
(4,702 Views)
That is correct.  I am performing commutation through the controller.  The documentation for the card says that if "Onboard Commutation" is selected as the commutation method (as opposed to "External Commutation"), then 2 of the analog outputs will be used to produce phase-shifted sinusoidal outputs.  The drive will produce the 3rd output.  This description coincides with the instructions supplied with the drive documentation.  So, the NI controller is performing the commutation.

-Ryan
0 Kudos
Message 3 of 16
(4,686 Views)
Ryan,

there is a chance, that this error is caused by an issue in an older version of NI-Motion. For the case that you are not using NI-Motion 7.6, please download this version, install it and perform a firmware upgrade for your 7358.

I hope this helps.

Kind regards,
Jochen Klier
National Instruments
0 Kudos
Message 4 of 16
(4,684 Views)
Hello again,
I performed the update you suggested (updating to the latest version of NI-Motion), and the install went successfully.  When re-opening MAX, I was prompted to update the motion control card (PXI-7358) to the latest firmware.  I went ahead and did that, and the install went successfully.  I then went ahead and tried to initialize the card as I described before (Axis 1 with Onboard Commutation) and got the same error as before (70069) relating to invalid Hall Sensor states.

Any ideas?

-Ryan
0 Kudos
Message 5 of 16
(4,658 Views)
Are you sure that the halls are wired correctly to the controller?   
0 Kudos
Message 6 of 16
(4,656 Views)
Yes, I verified that each of the Hall sensor signal inputs were tied to the Hall sensor inputs A, B, and C on the UMI board, and that all of the sensor grounds were tied to the board ground.
0 Kudos
Message 7 of 16
(4,653 Views)
Are you sure that the Halls are single ended?  They are quite often differential.  If that is the case, and the UMI takes single ended only, then you should not connect the inverted Hall leads to anything.
0 Kudos
Message 8 of 16
(4,650 Views)
The Hall sensors we are using have 3 wires...ground, +5V input, and signal output.  With the present wiring, I have the ground wires connected to the UMI ground, the +5V inputs connected to the UMI +5V output, and the signal output connected to the respective Hall sensor input channels on the board.  So, I believe this is appropriate wiring for a single-ended sensor.
0 Kudos
Message 9 of 16
(4,628 Views)

What is the make/model# of the motor?

Do you have access to a voltmeter or oscilloscope to verify that the halls are changing state as the motor is rotated by hand?

~~~~~~~~~~~~~~~~~~~~~~~~~~
"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~
0 Kudos
Message 10 of 16
(4,619 Views)