User manual

5
Technical Information
State Machine
Tab. 1
Profibus State Machine RS485 State Machine
Status Meaning Status Meaning
POWER_ON Interface set-up POWER_ON Interface set-up
WAIT_PRM Wait for parameterisation from the
master
SRC_ADDR Search for the controller serial
address
WAIT_CFG Wait for configuration from the
master
IDENTIFY Identify controller model and
protocol
DATA_EXCH Regular data exchange DATA_EXCH Regular data exchange
The two machines continuously share I/O data with the relative bus,
and interact each other only in following conditions:
 ProfiBus Data exchange is suspended (static diagnosis activated)
if the RS-485 serial link in not established
 RS-485 Data exchange is suspended (only for output data) if the
ProfiBus State machine is not in Data Exchange mode
As a general rule, unrecoverable communication errors make each
machine to jump to the state immediately following the power-on
state (WAIT_PRM or SRC_ADDR).
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