Image Processing Reference
In-Depth Information
Isochronous EPL cycle
Start period
Isochronous period
Asynchronous period
Idle period
Managing
node (MN)
Controlled
node 1 (CN1)
Controlled
node 2 (CN2)
Time
FIGURE .
EPL timing.
High-speed-Transmission-period (Tsyn)
Node 1
Node 2
Node 3
Time
FIGURE .
TCnet timing.
TABLE .
Performance Indicators for EPL
Performance Indicator
Profile /
a
Profile /
b
Delivery time
µs
. ms
Number of end-stations
Number of switches between end-stations
( Repeater)
( Repeaters)
Throughput RTE
. M octets/s
M octets/s
Non-RTE bandwidth
.%
.%
Time synchronization accuracy
<
s
<
s
Non-time-based synchronization accuracy
<
ns
<
ns
Redundancy recovery time
µs
. ms
a
Small-size automation system.
b
Large-size automation system.
The Application layer of the EPL is taken from the CANopen standards provided by the
CAN in Automation (CiA, see www.can-cia.org) organization []. CANopen standards define
widely deployed CPs, device profiles, and application profiles. Integration of EPL with CANopen
combines profiles, high performance data exchange, and open, transparent communication with
TCP/UDP/IP protocols. These CANopen profiles define process data objects (PDOs) to con-
trolthephysicalprocessandservicedataobjects(SDOs)whichareusedtodeinethebehav-
ior of the device as parameters or configuration data. The PDOs are transmitted with the
isochronous EPL communication, and the SDOs are transmitted with the UDP/IP protocol. Based
