The Industrial Raspberry Pi Forum

Can I use 24AC for the output power supply?

we have not written this explicitly in the Tutorial "Connecting the power supply" but it is a common industrial standard that power supply of PLCs and Sensors is always 24 DC. If you have a look on the DIO case you will find the power specification as demanded by En 61131:

12-24 VDC -15% 7 +20% (X2 & X4)

where X2 and X4 are the 2 power supply connectors.
The little diagram also shows you the symbol for transistor output. Together with the configuration parameter "high side switch" or "push-pull" this symbol explains that a DIO has semiconductor transistor outputs which are DC. Triac outputs or relays could be AC outputs but never transistor based high side switches or push pull outputs.
This said: if you connect 24 V AC on the X2 24 V / 0 V O(utput) power supply pins you will get a functioning result as our power supply input does rectify this Ac voltage to a DC voltage. But if your actuator needs AC it will not work as the output will show a DC signal (which will be less than 24 VDC as 24 VAC rectified might result in DC voltages much lower (depending on the current you draw).
We would not recommend such wiring because of this uncertainty of voltage level at the outputs.