Lenze E94AYCCA - Manual (Page 75)

EDS94AYCCA EN 5.0 - 06/2012
L
75
E94AYCCA communication manual (CANopen®)
Monitoring
Node guarding protocol
10.1.1 Telegram structure
RTR telegram
 The RTR telegram from the NMT master has the following identifiers:
Identifier (COB-ID) = 1792 + node address of the NMT slave
 The RTR telegram does not contain any user data.
 The RTR bit in the arbitration field of the RTR telegram is set to the valency LOW
(dominant level).
Response telegram
 The response telegram from the requested NMT slave has the same identifier as the
RTR telegram received by the NMT master.
 The user data (1 byte) contains the NMT slave status and the toggle bit (see the
following description).
NMT slave state (s)
Toggle bit (t)
 The toggle bit (t) in the response telegram has the value "0" when the node guarding
protocol is activated for the first time.
 The toggle bit (t) must change its value with each response.
NMT slave status Data
Communication status Decimal value
(s)
(t) NMT slave state (s)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Stopped 4 0/1 0 0 0 0 1 0 0
Operational 5 0/1 0 0 0 0 1 0 1
Pre-operational 127 0/1 1 1 1 1 1 1 1

Note!
The toggle bit is monitored by the NMT master.
If a telegram is received with a toggle bit value that has not changed compared
to the previously received telegram, it will be treated as if it were not received,
i.e. the monitoring time is not reset and elapses further.
The toggle bit can only be reset to the value "0" by the "Reset Communication"
telegram of the NMT master.