Midea M2OC-18HRDN1-M - Annex 2; Reference voltage data:

Annex 2
1. Reference voltage data:
a) Rectifier : Input :220-230V(AC), output :310V(DC)
b) Inverter module: U,V, W 3ph.
Result
U-V 60-150V(AC)
U-W 60-150V(AC)
V-W 60-150V(AC)
P-N DC 310V
c) Photo-couple PC817, PC851: Control side <+5V, AC side :< 24V(AC)
d) S terminal and N: changeable from 0-24V
2. Check the Diode Bridge component ( In wiring diagram, rectifier)
Remark: If this part is abnormal, the LED will not light.
Multi-meter Result
Forward Resistance Backward Resistance
+
_
Infinite Infinite
~
+
~500 ohm Infinite
~
-
~
~500 ohm Infinite
~
~ +
- ~