Resetting The Memory Of The Im 151/Cpu; Ways To Reset The Memory - Siemens SIMATIC IM 151/CPU Manual

Commissioning and Diagnostics
4.2

Resetting the Memory of the IM 151/CPU

When Do You Reset the Memory of the IM 151/CPU?
You must reset the memory of the IM 151/CPU if an entire new user program is to
be transferred to the CPU or if the STOP indicator is flashing at 1-second intervals.
The following are possible reasons for the MRES request:
The ET 200S is starting up for the first time.
The backup memory is inconsistent.
The user memory is inconsistent.
The memory module has been replaced.
How Do you Reset the Memory?
There are two ways of resetting the IM 151/CPU:
Table 4-2

Ways to Reset the Memory

Resetting the Memory with the Mode
Selector
Described in this chapter.
Resetting the Memory of the IM 151/CPU with the Mode Selector
To reset the memory of the IM 151/CPU using the mode selector, proceed as
follows (see also Figure 4-1):
1. Switch the mode selector to the STOP position.
2. Depress the mode selector in the MRES position. Leave it in this position until
the STOP LED comes on for the second time (corresponds to 3 seconds), and
then let it snap back to the STOP position again.
3. Within 3 seconds, you must press the mode selector back to the MRES position
and hold it in this position until the STOP LED flashes (at 2 Hz). When the
IM 151/CPU has completed the memory reset, the STOP LED stops flashing
and remains on.
The IM 151/CPU has reset the memory.
4-4
Resetting the Memory with the
Programming Device
Only possible during CPU STOP (see the
programming device manuals and the
STEP 7 online help system)
ET 200S Interface Module IM 151/CPU
A5E00058783-01