Memory concept
6.2 Memory functions
Note
The function "Download a user program from PG/PC" may be used only when the CPU is in
the STOP state.
Load memory is cleared if the load operation could not be completed due to power loss or
illegal block data.
Before you transfer projects to the Technology CPU via the MPI/DP interface, you should
increase the baud rate to at least 1.5 Mbaud or else the data transmission can take a very
long time (up to 15 minutes at 187.5 kbaud).
6.2.2 Downloading a user program (enhanced handling)
Download user program from PG/PC to MMC
You can choose one of three methods to download user data to the MMC:
• Download a new user program: You have written a new user program. You download all
the program data from PG/PC to the MMC.
• Download of blocks: You already written a user program and downloaded it to the MMC.
You then want to add new blocks to the user program. In this case, you do not need to
reload the entire user program to the MMC. Rather, you can download only the new
blocks to the MMC (this reduces download times for highly complex programs).
• Download an existing user program: In this case, you only download the deltas in the
blocks of your user program. In the next step, perform a delta download of the user
program, or only of changed blocks to the MMC, using the PG/MC.
Caution
The delta download of blocks / user programs overwrites all data stored under the same
name on the MMC.
The data of dynamic blocks are transferred to RAM and activated after the block is
downloaded.
Upload
Other than "download" operations, an upload operation is the transfer of specific blocks or a
user program
from the CPU to the PG/PC. The block content is here identical with that of the
last download to the MMC. Dynamic DBs form the exception, because their actual values are
transferred.
An upload of blocks or of the user program from the CPU in
STEP 7
does not influence CPU
memory.
S7-300 CPU Data: CPU 315T-2 DP
Manual, 12/2005, A5E00427933-02
6-11
To Next Page
Loading...
Need help?
General
