Hallo Tom,
After I asked you with a lot of question, finally I could found the problem.
The problem is simple : 1. I must executed DAQ_config before Select_Signal 2. The cable that conected from NiDAQ card to the machine is not shielded good enough to prevent the noise disturbance. 3. The cable that connect GND signal is not good enaough so that the signal also unstable.
Finally, Thank you Tom.
Best Regards
Susanto W
