CANopen information
3.6.1.2 NMT Node / Life guarding services
With the Node/Life guarding a NMT master can detect the failure of a NMT slave
and/or a NMT slave can detect the failure of a NMT master:
At the Node Guarding the NMT master requests the state of a NMT slave in regular
intervals. The toggle bit 2
Example:
0x85, 0x05, 0x85 ... --> no error
0x85, 0x05, 0x05 ... --> error
Additionally if the Life Guarding is active, the NMT slave requests the state of a NMT
master in regular intervals, otherwise the slave changes into the PRE-OPERATIONAL
state.
The
1110 bin: COB-ID 0x700+Node ID.
Index
0x100C Guard Time [ms]
0x100D Life Time Factor
Table 5: Parameter for NMT services
3.7 PDO mapping
PDO mapping refers to the mapping of application objects (real-time data, e.g. object
6004h "Position value" from the object dictionary into Process Data Objects, e.g.
Object 1A00h (1
The current mapping can be read via corresponding entries in the object dictionary,
the so-called mapping tables. The number of mapped objects that are listed
subsequently is found at the top of the mapping table (subindex 0). The tables are
located in the object dictionary at index 0x1600 ff. for the RxPDOs and 0x1A00ff for
the TxPDOs.
TR-Electronic GmbH 2010, All Rights Reserved
Page 116 of 183
Node Guarding and Life Guarding:
With these services a NMT master monitors a NMT slave
7
in the "Node Guarding Protocol" toggles after each request:
NMT
services
for
Description
st
Transmit PDO).
TR - ELA - BA - DGB - 0016 - 04
Node/Live
guarding
At termination of the time interval
Life Time = Guard Time x Life Time Factor [ms]
the NMT slave expects a state request by the master.
Guard Time = 0: No monitoring active
Life Time = 0: Life guarding disabled
use
the
function
Printed in the Federal Republic of Germany
01/20/2017
code