Getting started
Copyright IXXAT Automation GmbH
29
IEM Manual, 1.5
Variables located on host side
All variables which should be sent respectively received cyclically have to be
placed in the IO area. Contrary variables for acyclic transfer can be placed ei-
ther in the acyclic area of the shared memory or in the memory of the host.
To select the location and the access right, the application has to set certain
attributes
for
each
variable
inside
the
creation
command
of
. Multiple attributes could respectively have to be
set for each variable. The following matrix (Figure 2-7) shows the valid combi-
nations and the effect to the storage location.
COM_k_
ATTR_
PROCESS
COM_k_
ATTR_
WRITE
COM_k_
ATTR_
READ
COM_k_
ATTR_
HOST
COM_k_
ATTR_READ_
WRITE
COM_k_
ATTR_
PROCESS
IO Output
IO Intput
x
x
COM_k_
ATTR_
WRITE
IO Output
x
host
memory
x
COM_k_
ATTR_
READ
IO Input
x
host
memory
x
COM_k_
ATTR_
HOST
x
host
memory
host
memory
host
memory
COM_k_
ATTR_READ_
WRITE
x
x
x
host
memory
(-) single at-
tribute
x
acyclic
acyclic
x
acyclic
x = not possible
Figure 2-7: Matrix of variable attributes
The application is responsible to implement a scheme to manage and access
the variables on the host side. The provided demo application is using a ge-
neric structure to handle the variables regardless of the used protocol. Please
see chapter 2.3.11.1.5.