Functions of the IM 151/CPU
5-4
ET 200S Interface Module IM 151/CPU
A5E00058783-01
5.2 The Mode Selector and LEDs
Mode Selector
The mode selector of the IM 151/CPU is designed as a 3-step toggle switch (see
below):
RUN–P
STOP
MRES
Figure 5-1 Mode selector
Positions of the Mode Selector
The positions of the mode selector are explained in the order in which they are
arranged on the IM 151/CPU.
Table 5-2 Positions of the Mode Selector
Position
Description Description
RUN-P RUN-PROGRAM
mode
The CPU processes the user program.
STOP STOP mode The CPU does not process the user program.
Programs can:
Be read out from the CPU using a programming device
(CPU PG)
Transferred to the CPU (PG CPU)
MRES Reset CPU
memory
Momentary-contact position of the mode selector for resetting the
CPU memory.
You must adhere to a specific sequence when resetting the CPU
memory using the mode selector (see Section 4.2)