I have a cFP-1808 ethernet interface with 7 modules attached. One
is a cFP-QUAD-510. When I hook an encoder to this module and view
velocity/position measurements in MAX, I only get valid results if I
use the module's 5VDC regulator to power the encoder. The encoder
itself can take 5-24VDC, but when I try giving it 12VDC or 24VDC, I get
no new updates in MAX (i.e. the status is successful, the velocity
reads zero, and the time stamp doesn't change from when I first started
the task). While powering the encoder with these external
supplies, I put a scope on the encoder outputs and verified that they
are 90 deg offset square waves (with amplitudes at 11V and 22V
respectively) as expected. When I use the 12VDC or 24VDC
power supply as input to the 5VDC regulator and power the encoder off
that, everything seems to work perfectly. The only
difference between the two cases is the voltage level given to the
encoder. The manual for the cFP-QUAD-510 claims that it can
accept encoder levels as high as 30V. I'm testing now for a
future application where I won't have the option of powering an encoder
with the 5V regulator. What could be causing this problem?
Thanks,
Jeff