EM100-F User Manual
0084293
Page 73 of 93
6. CANopen Interface
6.1. General Interface Specification
11-bit Transmit and Receive Identifiers. Tolerates 29-bit Identifiers.
On start-up the EM100 waits for an NMT start message or SDO request
before transmitting anything (Note: This does not conform exactly to the
EM100 uses both Node Guarding and Heartbeat modes.
Node Guarding
The NMT master polls the network to obtain a data telegram from each node containing its current
communication state and a toggle-bit. If a node does not respond to the request of the NMT-master
within the ‘Node Life-Time’, it is assumed the node has failed. Also, the NMT-slaves monitor
whether they have received a request from the NMT-master within their ‘Life-Time’. If it takes longer
than the ‘Life-Time’ of a node, the NMT-slave assumes that the NMT-master itself has failed and if
in an ‘Operational’ state, it returns to a ‘Pre-Operational’ state.
Guard Time is the time in ms.
Index [100C] and [100D] are used if index [1017] is zero.
Note: Where network bandwidth is limited, or the application is safety sensitive, heartbeat mode, is
the preferred method to use node operation assurance.
Heartbeat
The heartbeat parameter is set by the NMT Master or the configuration tool in the EM100 slave
node. The interval (in ms) between two heartbeat messages, the ‘Heartbeat Interval’ of a heartbeat
producer is configured via index [1017]. A value of zero disables the heartbeat mechanism.
Heartbeats save network bandwidth since it does not require the NMT master to poll the slaves. If
index [1017] is non-zero the Heartbeat protocol is used, otherwise the Node-Guard protocol is used.
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