SQIO-DIN32DOUT32: Isolation

A creepage and clearance distance of 1.52mm (0.060”) is maintained between each bank of inputs or each bank of outputs and all other circuits.

Assuming that the local environment is pollution degree 1 and over voltage category II “known and controlled transient voltages,” this spacing according to

table D4 of IEC61010 corresponds to 300V of basic insulation.
table 35.2 of UL508C corresponds to 450V of isolation in equipment of 500VA rating or less and 225V or isolation for equipment rated 500VA-10kVA.

The purpose of the isolation is to avoid grounding problems and resist radio-frequency interference. It is not intended that the I/O should be connected to signals whose steady-state potential difference from ground exceeds 42.4Vdc.