Festo CMMP Series, Manual

Page: 47 / 210

5. Access Procedure
Festo P.BE-CMMP-CO-SW-EN 0708NH 47
5.6 Network Management (NMT Service)
All CANopen devices can be triggered via the Network Management. The identifier with
the highest priority (000h) is reserved for this.
By means of NMT, commands can be sent to one or all controllers. Each command
consists of two bytes, whereby the first byte contains the command specifier (
CS
) and the
second byte the node ID (
NI
) of the addressed controller. Through the node ID zero, all
nodes in the network can be addressed simultaneously. It is thus possible, for example,
that a reset is triggered in all devices simultaneously. The regulator does not acknowledge
the NMT commands. Successful completion can only be determined inderectly
(e.g. through the switch-on message after a reset).
Structure of the NMT Message:
Identifier:
000h Command specifier
Node ID
000
h
2 CS NI
Data length
For the NMT status of the CANopen node, conditions are established in a condition
diagram. Changes in conditions can be triggered via the
CS
byte in the NMT message.
These are largely oriented on the target condition.
NMT state Machine Meaning CS Target condition
2 Bootup -- Pre-operational 7Fh
3
Start Remote Node
01h
Operational
05h
4
Enter Pre-Operational
80h
Pre-operational
7Fh
5
Stop Remote Node
02h
Stopped
04h
6
Start Remote Node
01h
Operational
05h
7
Enter Pre-Operational
80h
Pre-operational
7Fh
8
Stop Remote Node
02h
Stopped
04h
9
Reset Communication
82h
Reset communication *
1)
10 Reset Communication 82h Reset communication * 1)
11 Reset Communication 82h Reset communication * 1)
12 Reset Application 81h
Reset application *
1)
13 Reset Application 81h
Reset application *
1)
14 Reset Application 81h Reset application *
1)
*
1)
The final target condition is pre-operational (7F
h
), since the
transitions 15, 16 and 2 are automatically performed by the
controller.
Tab. 5.2: NMT state Machine