ifm electronic JN2100 v.2.0 - Manual (Page 22)

Inclination sensor JN
22
7.13 Emergency messages
Every inclination sensor supports EMCY messages which are transmitted in the
event of sensor, temperature, hardware or guarding errors�
If one of these errors occurs, the entries in the object directory
● 1001h (error register)
● 1003h (pre-defined error field)
are updated�
After rectification of the error the device transmits an EMCY message with the
"error reset" code (0h) and the current state of the error and manufacturer status
register� The current device state ("pre-operational, operational or stopped") is not
influenced by the error states (except for guarding errors)�
7.14 Failure monitoring
As in a CANopen network the nodes do not respond regularly in the case of
an event-controlled transmission, heartbeat and node guarding/life guarding
mechanisms are available for failure monitoring�
Only one of the two monitoring methods can be used�
7.14.1 Node guarding / life guarding
Node guarding is the monitoring of one or several nodes by the NMT master�
The NMT master periodically transmits an RTR telegram to the slave to be
monitored which responds with its own status and a toggle bit�
If the status or toggle bit do not correspond to the response expected from the
guarding master or no response is given, the master assumes a slave error�
With this mechanism the node to be monitored can detect even the failure of
the guarding master�
To do so, two parameters are used� The interval time used by the guarding
master to check the sensor to be monitored is the "guard time" (100Ch)�
The second parameter is the life time factor (100Dh)� It defines a multiplicator
after which the connection is considered as interrupted�
This time is called node life time�
Node life time = guard time × life time factor
If the sensor receives no guarding request from the master within this
configured time, it assumes a master failure� It transmits an emergency
telegram and returns to the state "pre-operational"� If one of the two parameters
is "0" (default setting), the master is not monitored (no lifeguarding)�