Hi all,
I installed with a PCI-6221 card on my PC which is used to connected with the linear motion platflom through an Elmo Harmonica interface card. The card is detected correctly. It also past through self test and self calibrate under MAX. But when I test the encoder measurement in MAX or LabVIEW, it got some accuracy problem. I have configured the quadrature encoder followed the procedure:
- With NI Measurement & Automation Explorer open, select Data Neighborhood and click Create New.
- Select NI-DAQmx Global Virtual Channel and click Next.
- Select Acquire Signals » Counter Input » Position » Linear
- Select ctr0 to connect my encoder.
- ...........on the "Setting" tag, adjust the "Distance/Pulse" position to match the actual measurement correctly.
When I click "Run" and move the linear slider manually in one direction (e.g. from 0mm to 200mm), the encoder counting is corrected. But when I move back the linear slider oppositely to the initial position (from 200mm to 0mm), It willcount about 220 mm. The next cycle I move out and move back to initial position, it will count about 240 mm, and so on... The offset keep on to accumulate.
I try to connect to another PCI-6221 card which is installed on another PC, the symptom also same. So, I guess the PCI-6221 should be okay. Can anybody tell me what's wrong? how to solve the problem. Appreciate if someone can help. Thank you!
