I found that the ADC channels for IP_ANG had been assigned to a wrong machine.
IP_ANG is supposed to be acquired at c1auxey (east end), but actually it had been at c1auxex (south end).
This is the reason why we couldn't see any signals from IP_ANG.
So I fixed it by editing the db files (i.e. ETMXaux.db and ETMYaux.db). Now it seems working fine.
This mistake obviously came from the X-Y name swapping business. Something else might be still wrong.