6014 encoder

[antonio_ing_kth]

Dear all

I have to read an encoder that measures the angular position with signals A and B only (so no index Z). I use windows XP with labview 2011 and an acquisition card NI 6014. I have been able to count the individual signals with the application "Measurements and automation". I never read an encoder so I have used the express VI, but I have not found the option to read position in the express VI. When using an example named "measure angular position.vi", I have got continuously the error that the selected channel does not support the measurement type required. The property is "CI.MeasType", with a requested value "Position: Angular encoder", which is not available amongst the ones I have. How can I solve this?

Thank you very much for every hint. Happy new year...

antonio

[bronzacuerta]

Hi Antonio

I suppose that you can't acquire encoder position signal with the B series hardware PCI-6014. I think this is due due the onboard technology. I've searched some informations about but i have not found any document which explains the tasks that are avaliable using the specific hardware.

Any task can be implemented in MAX so a good way to understand if you can do a task with your hardware is to implement it in MAX. When you specify angular encoder acquisition task and you can't see any of the 6014 counters available in the list of channel, it means that you can't use the hardware to implement the task.

I think there is no workaround. You can't use Windows to read the encoder signals in a low level way (using software to transform the phase signals into a position measure) because Windows is not a real time OS.

Let me know you have any other idea!!!!!

[bronzacuerta]

You can understand if your task can be done through the following document

<http://zone.ni.com/reference/en-XX/help/370471W-01/cdaqmxsupp/pci-6014/>

For example using a PCI-6221 you can implement the angular encoder acquisition task and you can see it from

<http://zone.ni.com/reference/en-XX/help/370471W-01/cdaqmxsupp/pci-6221/>

Best regards!!!!!

[antonio_ing_kth]

Dear Bronzacuerta

thank you for the quick reply. I was starting to suspect it since I was able to count the edges now, but the channels A and B were very strange. Luckily I have another card available (a NI 6259) which is able to perform angular encoder measurements. Unluckily, it is installed in a Mac OS X computer and there is no ctr0 counter associated. I have tried with the labview utilities to read it but it says that there is no device to perform this action, while the analog inputs are all right. I will try to mount it in a PC and see if I am lucky. Thank you again for the info.

cheers