Fieldbus coupler/controller
• 73
Review
Modular I/O System
L
ON
W
ORKS
®
In addition, the controller offers further memory spaces.
A special memory space is reserved for the variables used for external con-
figuration. The binding of the configuration variables with the so-called Con-
figuration Properties (CPs) bind them permanently.
CPs are variables comparable to nvis that are used for the external controller
configuration via the LON network. As opposed to the nvis, the settings via
CPs are stored in the LNS data base and in the EEPROM of the Neuron-Chip.
Thus they are still available after a reset and they can be subsequently ac-
cessed when changing the node for example.
The address range of the configuration variables spans 128 double words.
The following memory spaces inside the controller cannot be accessed from
the fieldbus side:
RAM
The RAM memory is used to create variables not required for
communication with the interfaces but for internal processing, such
as computation of results.
The retain memory is a non-volatile memory, i.e. all values are
retained following a voltage failure. The memory management is
automatic. In this memory area, flags for the IEC 61131-3 program
are filed together with variables without memory space addressing
or variables which are explicitly defined with "var retain".
Retain
Note
The automatic memory management can cause a data
overlap. For this reason, we recommend not to use a mix
of flags and retain variables.
Code
mem-
ory
The IEC 61131-3 program is filed in the code memory. The code
memory is a flash ROM. Once the supply voltage is applied, the
program is transmitted from the flash to the RAM memory. After
an error-free start-up, the PFC cycle starts when the operating
mode switch is turned to its upper position or by a start command
from WAGO-I/O-
PRO
32.