User Manual

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Manual, 03/2014, A5E02486774-AF
345
Exchanging a V3.0 CPU for a V4.0 CPU
B
B.1
Exchanging a V3.0 CPU for a V4.0 CPU
You can replace your V3.0 CPU with a V4.0 CPU (Page 74) and use your existing STEP 7
project that you designed for the V3.0 CPU. You might also want to check for and apply
firmware updates (Page 269) to your connected modules.
Note
No device exchange possible from V4.0 to V3.0
You can exchange a V3.0 CPU for a V4.0 CPU, but you cannot exchange a V4.0 CPU for a
V3.0 CPU after you download the configuratio
n. If you want to view or otherwise use your
existing STEP
7 V3.0 project, make an archive of your STEP 7 V3.0 project prior to the
device exchange.
Note that if you have not downloaded the exchanged device configuration, you can undo it.
After downloadin
g, however, you cannot undo the exchange from V3.0 to V4.0.
You need to be aware of some configuration and operational changes between the two CPU
versions:
Organization blocks
With V4.0, you can configure OB execution to be interruptible or non-interruptible (Page 55).
For projects from former V3.0 CPUs, STEP 7 sets all OBs by default to be non-interruptible.
STEP 7 sets all OB priorities (Page 55) to the values they were in the V3.0 CPU STEP 7
project.
You can subsequently change the interruptability or priority settings if you choose.
The Diagnostic error interrupt OB start information references the submodule as a whole if
no diagnostics event is pending.
CPU password protection
STEP 7 sets the password protection level (Page 82) for the V4.0 CPU to be the equivalent
password protection level that was set for the V3.0 CPU, and assigns the V3.0 password to
the "Full access (no protection)" password for the V4.0 CPU:
V3.0 protection level
V4.0 access level
No protection
Full access (no protection)
Write protection
Read access
Write/read protection
HMI access
Note that the V4.0 access level "No access (complete protection)" did not exist for V3.0.