Siemens SIMATIC PC 670 Equipment Manual page 30

Starting Up the Computing Unit
Additional permissible installation position for the computing unit complying
with UL508/CSA 22.2 No. 142
An installation angle of 15_ is permitted in this position.
Note
The possible installation locations for the computing unit do not agree with the
permissible installation location of Panel PC 670 (refer to the commissioning
instructions).
2-6
Position 5
(interfaces at bottom)
Panel PC 670 Computing Unit, Equipment Manual
Release 04/02