WAGO -I/O-SYSTEM 750 Manual page 89

WAGO-I/O-SYSTEM 750
750-882 Media Redundancy ETHERNET Controller
The subsequent memory area, starting from word 1532, is reserved for future
protocol expansion and other PFC variables.
In addition, all output data is mirrored in the Media Redundancy ETHERNET
Controller to a memory area with the address offset 0x0200 and 0x1000. This
allows output values to be read back in by adding 0x0200 or 0x1000 to the
MODBUS address.
Other memory areas are also provided in the controller, some of which cannot be
accessed by the fieldbus side, however:
• Data memory (512 kByte)
The data memory is a volatile RAM memory for creating variables that are
not required for communication with the interfaces, but rather for internal
processing procedures, such as calculation of results.
• Program memory (1 MByte)
The IEC-61131-3 program is stored in the program memory. The code
memory is a Flash ROM. When power is switched on, the program is
transferred from the flash to the RAM memory. After error-free run-up, the
PFC cycle starts with the mode selector switch at the top position, or on the
Start command from the WAGO-I/O-PRO.
• NOVRAM Remanent memory (32 kByte)
The remanent memory is a non-volatile memory; i.e., all values of flags and
variables, that are explicitly defined by "var retain", are retained even after a
loss of power. Memory management is performed automatically. The
32 kByte memory area is normally divided into an 16 kByte addressable
range for flags (%MW0 ... %MW 8191) and a 16 kByte retain area for
variables without memory area addressing, that are defined by "var retain".
Markers are only remanent under "var retain"!
Please note that the bit memory is only retentive if you have declared it as such
under "var retain".
Function Description
Manual
89
1.5.0