Can I set the operation mode to DO and then perform contact output?

This is possible with the UT500/UT700. With the registered contact output parameters, assign relay number in each mode.

UT520 Digital Indicating Controller

The UT520 Digital Indicating Controller was discontinued on 1/01/2010. The UTAdvanced UT52A is a replacement product.
UT550 Digital Indicating Controller

UT550 Digital Indicating Controller
UT551 Digital Indicating Controller

UT551 Digital Indicating Controller
UT750

Highly functional 1/4 DIN sized Controller comes with Custom Computing and 12 powerful control functions including dual-loop control. It also features easy-to-see large PV display and LCD display for interactive setting and programming. The universal I/O, auto-tuning, "SUPER" and "SUPER2" functions are standard. Two ports of RS-485 communication are option.