Festo CiA 402 Manual page 43

3 CANopen access procedure
a specific bit is inverted (toggled). If these responses are not made or the motor controller always re-
sponds with the same toggle bit, the master can react correspondingly. Likewise, the drive monitors the
regular arrival of the Nodeguarding requests from the master: If messages are not received for a certain
time period, the motor controller triggers error 12-4. Since both the Heartbeat and Nodeguarding tele-
grams ( Section 3.6.7) are sent with the identifier 700
simultaneously. If an attempt is made to activate both protocols simultaneously, only the Heartbeat
protocol will be active.
Structure of the Nodeguarding messages
The master's request must be sent as a so-called remote frame with the identifier 700
the case of a remote frame, a special bit is also set in the telegram, the remote bit. Remote frames have
no data.
Identifier: 700
h
701 R
h
Remote bit (Remote frames have no data)
The response of the motor controller is constructed analogously to the Heartbeat message. It contains
only 1 byte of user data, the toggle bit and the NMT status of the motor controller (
Identifier: 700
h
701 1
h
Data length
The first data byte (T/N) is constructed in the following way:
Bit Value Name
7 80 toggle_bit
h
0 ... 6 7F nmt_state
h
The monitoring time for the master's requests can be parametrised. Monitoring begins with the first
received remote request of the master. From this time on, the remote requests must arrive before ex-
piration of the set monitoring time.
The toggle bit is reset through the NMT command Reset Communication. It is therefore not set in the
first response of the motor controller.
Festo – GDCP-CMMS/D-C-CO-EN – 1404NH – English
+ node ID (example node ID 1)
0
+ node ID (example node ID 1)
Toggle bit / NMT status
T/N
+ node ID, both protocols cannot be active
h
Significance
Changes with every telegram
00 Boot-up
h
04 Stopped
h
05 Operational
h
7F Pre-Operational
h
+ node ID. In
h
Chapter 3.6).
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