having a quick look at the UB1 manual
I would connect the drivers fault output +FLT to a UB1 input plus a 2K2 pull up resistor from +25V and -FLT to the UB1 input 0V/gnd
if your not using all axis outputs you may be able to connect the EM806 driver Enable inputs to the C axis outputs CD + CD- or Cs+ CS- for example if your control software will let you
As the UB1 outputs sink upto 70mA when a load is connected between +24V and an output you will need to add a 2K2 dropper resistor to limit the current into the EM806 drivers 5V enable input
john