Commissioning

6.5Resetting the CPU with the Mode Selector Switch

How to Carry Out a Memory Reset

When you reset a CPU, you place the memories of the CPU in a defined initial state. The CPU also initializes its hardware parameters and some of the system program parameters. If you have inserted a Flash card with a user program in the CPU, the CPU transfers the user program and the system parameters stored on the Flash card into the main memory after the memory reset.

When Should a CPU be Reset?

You must reset the CPU:

Before transferring a new, complete user program to the CPU.

When the CPU requests a reset. Your recognize this request by slow flashing of the STOP LED at 0.5 Hz.

How to Perform a Memory Reset

There are two ways of resetting the CPU:

Reset with the mode selector switch

Reset from the programming device (see STEP 7)

Resetting the CPU with the mode selector is described in the following section.

Automation System S7-400

Hardware and Installation

6-7

A5E00850741-01

 

Page 135
Image 135
Siemens S7-400 installation manual Resetting the CPU with the Mode Selector Switch, How to Carry Out a Memory Reset