Communication and protocol, Nmt state machine, Figure 2: nmt state machine – NORD Drivesystems BU2200 User Manual
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4 Communication and Protocol
12
BU 2200 GB-3813
4. Communication and Protocol
Pos : 29 /Anl eitungen/ Elektroni k/ Bus s yst eme/4. Kommuni kati on und Prot okoll + Proz ess datentr ans fer /POWER LIN K [ BU 02200]/NMT St at e M asc hine @ 4\ mod_1378716830672_388.doc x @ 93762 @ 2 @ 1
4.1 NMT State Machine
The NMT State Machine defines various communication states of the module.
Figure 2: NMT State Machine
State
Explanation
Init
No communication of process data and parameters
The bus is monitored for POWERLINK frames. If no corresponding frame is received
within the set time window (timeout), the interface switches directly to the status
BASIC_ETHERNET. However, if a POWERLINK communication is detected before the
time expires, the interface switches directly to the status PRE_OPERATIONAL_1.
Pre- Operational 1
Parameter communication active, no process data communication
The CN waits for the reception of an SoC frame and then switches to the status
PRE_OPERATIONAL_2. If the red LED lights up in this state, this means that the
Manager has failed.
Pre- Operational 2
Parameter communication active, no process data communication
In this state, the interface is usually configured by the Manager. After this, a command is
given to switch to the state READY TO OPERATE. If the red LED lights up in this state,
this means that the Manager has failed.
Ready To Operate
Parameter communication active, restricted process data communication
Configuration of the interface is complete. Normal cyclic and asynchronous
communication. The transmitted PDO data correspond to the PDO Mapping. However,
cyclic data are not evaluated. If the red LED lights up in this state, this means that the
Manager has failed.
Initialisation
not Active
Basic Ethernet
Pre-Operational 1
Operational
Ready to Operate
Pre-Operational 2
Error Condition