Communication Protocols
Copyright IXXAT Automation GmbH
125
IEM Manual, 1.5
mote device. Using SDO-Read and SDO-Write for the same variable is only
possible if the variable is located on the host controller or in the acyclic data
area of the SHM. Figure 5-30 gives an overview about the Relation between
EMI and Powerlink services depending on the access rights and location of the
variable.
Location
Access rights
Services
Host
SHM
cyclic
SHM
acyclic
write
read
read /
write
EMI service
(local request)
EPL service
(remote request)
1
x
x
SET_VALUE
SDO-Read
2
x
x
GET_VALUE
SDO-Write
3
x
x
SET_VALUE
GET_VALUE
SDO-Read
SDO-Write
4
x
x
SET_VALUE
SDO-Read
5
x
x
GET_VALUE
SDO-Write
6
x
No!
7
x
x
SET_VALUE
SDO-Read
8
x
x
GET_VALUE
SDO-Write
9
x
x
SET_VALUE
GET_VALUE
SDO-Read
SDO-Write
x = choosen; No! = not possible
Figure 5-30: Relation between EMI and Powerlink services
5.4.2 Process data mapping
In Ethernet POWERLINK the objects that are located in the cyclic section of
the shared memory can be mapped to a process image. The mapping process
can be configured according to [EPL1] either from the Managing Node (MN) or
by initializing the objects according [EPL1] from the host.
5.4.3 Synchronization to IEM
When using Powerlink it is possible to synchronize the host to the Powerlink
SoC cyclic event. When the IEM receives an SoC frame, it will generate an
interrupt signal which the host can trigger (callback function that was regis-
tered by BSP_InterruptExtInit()). On availability of this signal, the latest data
received from the network during the last cycle is now available on the IEM.
Also the IEM now samples the process image that will be sending in the next
cycle.
5.4.4 LEDs
The following LEDs are used by the IEM’s Powerlink implementation:
