Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual page 94

Installing
5.2 Installing the mounting rail
Installing the mounting rail
1. Install the mounting rails so that sufficient space is available for installing modules and to
2. Mark up the mounting holes on the mounting surface. Drill the holes,
3. Screw the rail (M6 screws) onto the mounting surface.
The figure below shows the clearance required for the installation of an S7-300.
5-6
allow heat dissipation (clearance of at least 40 mm above and below the modules. See
the figure below).
diameter = 6.5 mm.
+0.2
Note
Always make sure of a low-impedance contact between the rail and a mounting surface,
if the latter is a grounded metal panel or equipment mounting panel. On varnished or
anodized metals, for instance, use a suitable contacting agent or contact washers.
40 mm
20
mm
40 mm
SIEMEN S
Operating Instructions, Edition 08/2004, A5E00105492-05
20
mm
S7-300, CPU 31xC and CPU 31x: Installation