Altivar Process ATV900 - Page 25

Basics
NHA80945 04/2017 25
Node Guarding Frame Description
The drive indicates its NMT state via the "NMT information field, described here:
Bit 6-0 (node state): Current NMT state of the drive:
 Initialization (00 hex)
 Stopped (04 hex)
 Operational (05 hex)
 Pre-Operational (7 F hex)
Bit 7 (toggle bit): The value of this bit must alternate from one drive response to the other. The value of the
toggle bit for the first response following activation of the node Guarding service is 0. This bit can only be
reset by sending the Reset_Communication command to the drive. If a response is received with the
same toggle bit value as the previous one, the new response is treated as if it had not been received.
Heartbeat Service
If you do not activate the node Guarding service described above, you can use the Heartbeat service to
monitor communication with another node that supports this service.
The Heartbeat service is deactivated by default on the Altivar.
Each Heartbeat Producer sends Heartbeat messages at regular intervals (Producer Heartbeat
Time).
All Heartbeat Consumer check that they receive these messages in a time less that the Consumer
Heartbeat Time.
The Producer Heartbeat Time must be less that the Consumer Heartbeat Time. If the drive has
been configured as a consumer and a period equal to the Consumer Heartbeat Time elapses without
a Heartbeat message being received, the drive triggers a Heartbeat event and send an emergency
telegram (EMCY).
Heartbeat Frame Description
The Heartbeat message sent from the drive contains a Heartbeat Producer state field (byte 0),
described here:
Bit 6-0: Heartbeat Producer state: Current NMT state of the drive:
 Initialization (00 hex)
 Stopped (04 hex)
 Operational (05 hex)
 Pre-Operational (7F hex)
Bit 7 (toggle bit): Reserved: This bit is equal to 0.
COB ID Byte 0 Byte 1
1792 (700 hex) + Node ID Bit 7 Bit 6 - 0
Toggle bit Node State
COB ID Byte 0
1792 (700 hex) + Node ID Bit 7 Bit 6 - 0
Reserved Heartbeat Producer State