beautypg.com

Siemens Automation System S7-400 User Manual

Page 29

background image

Installing the S7-400

2-13

Automation System S7-400 Hardware and Installation

A5E00850741-01

Mounting Screws

You have a choice of the following types of screw for securing a rack:

Screw Type

Explanation

M6 cylinder-head screw to

ISO 1207/ISO 1580 (DIN 84/DIN 85)

Choose the screw length according to your

assembly.

You also need “6 4” washers to ISO 7092

M6 hex. screw to ISO 4017 (DIN 4017)

You also need “6.4” washers to ISO 7092

(DIN 433).

Step 3: Connecting the Rack to the Chassis Ground

Connect the rack to the chassis ground. A threaded bolt is provided for this
purpose on the bottom left of the rack.

Minimum cross-section of the conductor to the chassis ground: 10 mm

2

.

If the S7-400 is mounted on a mobile rack, you must provide a flexible conductor to
the chassis ground.

Note
Always ensure that there is a low-impedance connection to the chassis ground

(see the figure below). You achieve this with the shortest possible, low-resistance

conductor with a large surface to establish large-area contact.

M6 threaded bolt

Terminal

Plain washer

Contact washer

M6 nut

To chassis ground