Establishment of IO-Link communication

Establishment of IO-Link communication

The establishment of the IO-Link communication is illustrated in Fig. Establishment of IO-Link communication. This illustrates in particular the sequence when automatically scanning the IO-Link port.

Establishment of IO-Link communication 1:
Establishment of IO-Link communication
  • If an IO-Link device is connected to a master port, the master attempts to establish communication. A defined signal level, the WakeUp pulse, signals to the slave that UART bytes are to be sent from now on.
    From this point on, all data will be interpreted by the IO-Link slave as UART bytes.
  • The master runs through all baud rates, starting with the fastest baud rate (COM3 = 230 kbaud). A successful connection has been established when the slave responds to the WakeUp pulse.
  • First of all the master reads the basic parameters (Vendor ID, Device ID, process data length, telegram type and cycle time) and compares them with the existing configuration.
  • If no connection could be established to the slave, or if the saved parameters differ from those read, the corresponding error is output.
  • If the saved parameters differ from those read, the IO-Link device changes to the PREOP state.
    If the IO-Link device specification is V1.1, the parameter server is now executed. If the IO-Link device specification is V1.0, this step is omitted and the device changes directly to OP.
  • Finally the cycle time is written and the device changes to OP. After that the master cyclically exchanges data with the slave.