Issue
159 October 2003
Embedded
Networking with MicroMessaging
STANDARD
CANopen TOOLS
After
the messages on a Micro-Messaging network are converted
by a gateway to a CANopen network, you can use standard
CANopen monitoring, analysis, configuration, and test
tools. Photo 2 shows the Network Overview window of
PCANopen Magic. The network consists of MicroMessaging
nodes 3 and 5 sharing a network with regular CANopen
nodes 7 and 65.
|
(Click
here to enlarge)
|
Photo
2—In this instance, the scan cycle of a network
consists of two regular CANopen nodes (7 and 41)
and two MicroMessaging nodes (3 and 5 with 11-bit
message ID representation). All four nodes were
found. |
After
the MicroMessaging traffic is transposed to a CANopen
network, the MicroMessaging nodes look and behave like
any other minimal CANopen nodes. Photo 3 shows the standard
CANopen service data object (SDO) accesses made by PCANopen
Magic to read the device type information from the error
register and the identity record from the MicroMessaging
node 3.
|
(Click
here to enlarge)
|
Photo
3—The trace display shows the regular CANopen SDO
requests and responses used to access service data
in the MicroMessaging node 3. |
FUTURE
UPGRADE
Although
MicroMessaging is primarily intended to provide a common
network protocol for applications using different network
types, it’s also suitable for applications that are
based on only one network technology. Most systems grow
over time, and even though today’s application may only
use one network technology and a limited number of nodes,
using MicroMessaging ensures future upgradeability.
More nodes are easily added (even when using other network
technologies), and the entire communication layout is
CANopen-compatible enough that standard CANopen tools
for monitoring, analyzing, configuring, and testing
are usable with MicroMessaging. In addition, note that
the ESAcademy tutors adopted the General Public License
as specified by GNU for MicroMessaging, so the entry
costs are extremely low.
