PN/CAN Gateway, PROFINET/CANopen Slave | Version 2 | 1/26/2021
18
5.3.3
Network management
Network status (NMT states):
Each CANopen device can have various system states. After the device is switched on, an internal
system initialization is carried out (hardware initialization, RAM test, setup of the basic objects). After
successful initialization, a boot up frame [COB-ID: 700
hex
+ node ID / data (1 byte): 00
hex
].
After this, the device is ready for operation and in the Pre-Operational state. Although the device's
parameters can be configured in this state (SDOs can be read and written), it will not transfer process
data objects (PDOs).
With the NMT command "Operational" [COB-ID: 000
hex
/ data (2 bytes): 01
hex
node ID], a CANopen
device can be switched to the operational status. Once in the Operational state, the coupler's process
data will be enabled (RPDO/TPDO communications will be running). The options available for
making changes to SDOs may be limited.
With the NMT command "Pre-Operational" [COB-ID: 000
hex
/ data (2 bytes): 80
hex
node ID], a
CANopen device can be switched to the pre-operational status.
With the NMT command "Reset (Application)" [COB-ID: 000
hex
/ data (2 bytes): 81
hex
node ID], a
restart of a CANopen device is triggered.
With the NMT command "Reset Communication" [COB-ID: 000
hex
/ data (2 bytes): 82
hex
node ID], the
CANopen communication of the device is reset. The device is subsequently in the Pre-Operational
state.
SYNC:
The SYNC frame is a periodic "Broadcast" frame and is a trigger for CANopen functions. The SYNC
frame makes it possible to transfer input data in a synchronized manner and to activate output data
simultaneously throughout the whole system. In order to ensure that the intervals at which the SYNC
frame are sent are equally spaced, the frame has a high priority level. [COB-ID: 80
hex
]
