This section describes the memory size for different areas of the Magelis SCU HMI Controller.
The memory size of the controllers is 128 Mbytes.
The table presents the memory specifications of the non-HMI control component:
|
Area |
Element |
Size (bytes) |
|---|---|---|
|
System Area |
System area reserved memory |
131072 |
|
System and diagnostic variables |
||
|
Physical input addresses (%I) |
256 |
|
|
Physical output addresses (%Q) |
256 |
|
|
Retain variables (1) |
16360 |
|
|
Persistent retain variables |
2044 |
|
|
Application Area |
Compiled control application |
1024000 |
|
User Area |
Symbols |
Dynamic allocation of 1228800 |
|
Variables |
||
|
Libraries |
||
|
(1) Not all of the 16360 bytes are available for the customer application because some libraries may use retain variables. |
||
The memory is composed of four areas:
ocontroller dedicated application memory
ocontroller OS memory
oHMI application memory
oHMI OS memory
Memory containing Persistent and Retain variables is preserved and protected. The Persistent and Retain variables will be retained during power outages or when the HMI controller is powered off.
System and Diagnostic Variables
|
Variables |
Description |
|---|---|
|
PLC_R |
Structure of HMI controller read-only system variables. |
|
PLC_W |
Structure of HMI controller read/write system variables. |
|
ETH_R |
Structure of Ethernet read-only system variables. |
|
ETH_W |
Structure of Ethernet read/write system variables. |
|
SERIAL_R |
Structure of Serial Lines read-only system variables. |
|
SERIAL_W |
Structure of Serial Lines read/write system variables. |
For more information on System Variables, refer to the Magelis SCU SoMachine PLCSystem Library Guide.
|
Library Name |
Average Size |
Comment |
|---|---|---|
|
10 kbytes |
Depends on the functions used. |
|
|
25 kbytes |
Always embedded in the application. The use of the functions does not consume additional memory. |
|
|
10 kbytes |
Depends on the functions used. |
|
|
PLC Communication |
20 kbytes |
Depends on the functions used. |
|
CANopen Stack |
115 kbytes |
Depends on the functions used. Each CANopen Slave consumes approximately an additional 10 kbytes of memory. |
|
23 kbytes |
Depends on the number of connections. |
Differences Between Byte Addressing and Word Oriented IEC Addressing
See the table below for a comparison of byte addressing and word-oriented IEC addressing for bits, bytes, words, and dwords. It visualizes the overlapping memory areas in case of byte addressing mode (see the example below the table).
Concerning the notation, consider that, for bit addresses, the IEC addressing mode is always word-oriented. This means that the place before the dot corresponds to the number of the word, the place behind names the number of the bit.
Comparison of byte and word oriented addressing for the address sizes D, W, B and X:
|
DWORDS/WORDS |
Bytes |
X (bits) |
|||
|---|---|---|---|---|---|
|
D0 |
W0 |
B0 |
x0.7 |
... |
x0.0 |
|
B1 |
x1.7 |
... |
x1.0 |
||
|
W1 |
B2 |
|
|
|
|
|
B3 |
|
|
|
||
|
D1 |
W2 |
B4 |
|
|
|
|
B5 |
|
|
|
||
|
W3 |
B6 |
|
|
|
|
|
B7 |
|
|
|
||
|
D2 |
W4 |
B8 |
|
|
|
|
... |
|
|
|
||
|
... |
... |
|
|
|
|
|
... |
|
|
|
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Example for overlapping of memory ranges in case of byte addressing mode:
oD0 contains B0...B3
oW0 contains B0 and B1
oW1 contains B2 and B3
oW2 contains B4 and B5
In order to get around the overlap do not use W1 or D1, D2, D3 for addressing.
