PLCopen motion control
Parameter manual b maXX
®
1000
Document no. 5.07004.03
179
of 208
m Heartbeat protocol
The heartbeat protocol is responsible for the monitoring of the slave(s) by the master. The difference to node
guarding is that there are no RTR-frames, rather the slave transmits cyclic heartbeat messages. One or several
heartbeat consumers receive or monitor the heartbeat messages. If the heartbeat message is not transmitted
within the set heartbeat time, the master (heartbeat consumer time in Object 1016
hex
) triggers a heartbeat
event. With the slave, the heartbeat producer time is set in Object 1017
hex
.
The current communication state of the slave can be recognized from the slave heartbeat message. The heart-
beat message frame consists of one data byte.
r: Reserved
s: Field “s” differs according to the communication state.
Either node guarding or heartbeat is supported each time. If the Heartbeat time is not equal to NULL, the Heart-
beat protocol will be activated.
m Service data (SDO)
Segmented SDO transfer and Block SDO transfer are currently not used by b maxx
®
1000.
The function of service data objects (SDOs) is to exchange messages without real time requests. Therefore
low-priority COB IDs are provided for this in the predefined connection set. SDOs are used for parameterizing
slaves and for setting the communication relationships for PDOs. Data access takes place exclusively via the
object list. SDOs are always confirmed data, i.e. the transmitter receives an acknowledgement from the receiv-
er. Data exchange via SDOs can only progress asynchronously.
SDOs follow the client-server model, the client initiates the communication and the sever responds. A server
cannot begin an SDO communication. The b maxx
®
1000 supports one server SDO and not client SDOs:
Communication phase Identifier s
Boot up 00
hex
PRE-OPERATIONAL 7F
hex
(127)
OPERATIONAL 05
hex
(5)
STOPPED 04
hex
(4)
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