Parameter data exchange
An intelligent IO-Link sensor/actuator can support parameterization by ISDUs (Indexed Service Data Unit). The PLC must explicitly query or, when marked as such, send these acyclic service data.
 | ISDU access TwinCAT supports access via ADS and via the CoE directory. |
The respective parameter is addressed via the so-called ISDU index. The following ranges are available:
Designation | Index range |
|---|---|
System | 0x00..0x0F |
Identification | 0x10..0x1F |
Diagnostic | 0x20..0x2F |
Communication | 0x30..0x3F |
Preferred Index | 0x40..0xFE |
Extended Index | 0x0100..0x3FFF |
| The range 0x4000 to 0xFFFF is reserved |
The use and implementation of these ranges is the responsibility of the sensor/actuator manufacturer. For clarification, just a few of the possible indices are listed here. Please take a look at the relevant chapter “Object description and parameterization”.
Index | Name |
|---|---|
0010 | Vendor Name |
0011 | Vendor Text |
0012 | Product Name |
0013 | Product ID |
0015 | Serial Number |
0016 | Hardware Revision |
0017 | Firmware Revision |
... | ... |
IO-Link operating modes
The IO-Link ports on the IO-Link master can be operated in the following nine modes (see Object description and parameterization - IO-Link State, Index 0xA0n0:01):
- INACTIVE: Statemachine is inaktive
- DIGINPUT: The port behaves like a digital input
- DIGOUTPUT: The port behaves like a digital output
- ESTABLISHCOMM: The IO-Link wakeup sequence is running
- INITMASTER: Readout the IO-Link device and check the communication parameters
- INITDEVICE: Initialization of the IO-Link device
- PREOPERATE: Parameter server is running
- OPERATE: The port is used for IO-Link communication
- STOP: Communication is stopped (COM-stop)