Hi,
best I've found is a pic of the drive and they look to be analogue input.
Ordinary analogue to digital and digital to analogue is, with most hobbyist controllers, 10, 12 or maybe 14 bit.
Eminently suitable for measuring temperatures and other sensors but not nearly quality enough for analogue servos.
For analogue servos you require high linearity 16 bit conversions or suffer significant loss of position accuracy.
The boards already recommended are the only suitable boards with the high quality analogue conversions.
Craig