Panel fit and I/O density
The 6ES7223-1PM22-0XA8: The physical footprint is 62 mm deep, 196 mm wide, and 80 mm tall. That 196 mm width dominates panel layout — it is roughly three times wider than the 16-input/16-output variant (6ES7223-1PL32-0XB0 at 70 mm). A panel grommet or gland plate sized for the narrower sibling will not accept this module without a DIN-rail reposition.
Comparison with 6ES7223-1PL32-0XB0
The closest same-series sibling is 6ES7223-1PL32-0XB0: a 16-input, 16-relay-output at 70 mm wide with multiple global approvals (cULus, FM, KC, CSA, RCM). It supports 10 ms max response, diagnostic alarm, and parameterization.