JVL MAC050 - Page 235

JVL A/S - User Manual - Integrated Servo Motors MAC050 - 4500 231
5.6 Expansion Mod. MAC00-FC2/FC4/FC41
The figure below show a Node Guarding/Life Guarding protocols
Where s is the state of the NMT slave:
t: is the toggle bit, it alternate between 2 consecutive responses from the NMT Slave.
The value of the toggle-bit of the first response after the guarding protocol becomes ac
-
tive, is 0. The Toggle Bit in the guarding protocol is only reset to 0 when the NMT mes-
sage Reset Communication is passed (no other change of state resets the toggle bit). If a
response is received with the same value of the toggle-bit as in the preceding response
then the new response is handled as if it was not received.
Heartbeat:
With the Heartbeat protocol, a Heartbeat Producer cyclically sends its communications
state to the CAN bus. One or more Heartbeat Consumers receive the indication. The
relationship between producer and consumer is configured via the object dictionary. The
Heartbeat Consumer guards the reception of the Heartbeat within the Heartbeat Con
-
sumer time. If the Heartbeat is not received within the Heartbeat Consumer Time a
Heartbeat Event will be generated.
s NMT state
4 Stopped
5 Operational
7 Pre-operational
TT1083GB
Request
Confirmation
Request
Confirmation
Indication
Node
Guard
time
Node
Life
time
Indication
Response
Indication
Response
Remote transmit request
COB-ID = 700h + Node-ID
COB-ID = 700h + Node-ID
Remote transmit request
Indication
7
t
6....0
s
7
t
6....0
s
Node Guarding event Life Guarding event
TT1084GB
Request
Heartbeat
producer time
Request
Indication
Heartbeat Event
COB-ID = 700h + Node-ID
Indication
7
r
6....0
s
7
r
6....0
s
Heartbeat
consumer time
Heartbeat
consumer time
Heartbeat producer
Heartbeat consumer