Technical Manual N5 (CANopen)
8 CANopen
2. Deactivate the mapping by setting subindex 00h of the corresponding mapping parameter (e.g.,
1600
h
:00
h
) to "0".
3. Change the mapping in the desired subindices (e.g., 1600
h
:01
h
).
4. Activate the mapping by writing the number of objects that are to be mapped in subindex 00h of the
corresponding mapping parameter (e.g., 1600
h
:00
h
).
5. Activate the PDO by setting bit 31 of subindex 01h of the corresponding communication parameter
(e.g., 1400
h
:01
h
) to "0".
8.2.6 Boot-Up Protocol
If the CAN slave reaches the "Pre-Operational" NMT state (see following figure), the following message
is sent to signal operational readiness.
CAN ID
Data
Byte 0
700+NodeID
0x00
BOOTUP Message
This service is unconfirmed; there is no response.
Note
The boot loader sends its own boot-up message. This can be suppressed, see object 2007
h
:00
8.2.7 Heartbeat and nodeguarding
With the "heartbeat" and "nodeguarding" services (often also referred to as "lifeguarding"), switched-
off or hung devices on the CAN bus can be detected. For this purpose, the NMT master cyclically
requests a message with the current NMT state of the slave (nodeguarding). The alternative is that
each slave sends a message unprompted and cyclically (heartbeat). A combination of nodeguarding
and heartbeat is not permissible. Furthermore, it is recommended that heartbeat be given preference
over nodeguarding, as nodeguarding results in a higher load on the CAN bus.
Nodeguarding
This service is based on the fact that the NMT master sends an RTR message with CAN-ID 700
h
+
node-ID to the respective slave. The slave must then send a message as response; this message is
structured as follows. Bit 7 alternates here on each transfer, thereby allowing one to determine if a
message was lost. Entered in bits 6 to 0 is the current NMT status of the slave.
Version: 2.0.1 / FIR-v1650
119
