Glossary · Industrial communication
Service data
Also known as: Acyclic data, Parameter data
German: Servicedaten
In industrial communication, service data are the non-time-critical data exchanged on demand with a device, such as parameters, configuration, identification, diagnostic information and firmware, as opposed to cyclic process data.
- Industrial communication
In one sentence
Service data are on-demand, non-time-critical device data such as parameters, identification and diagnostics.
Example
During commissioning, the tool writes the motor rated current and the acceleration ramp to a drive as service data via CANopen SDOs.
How it applies
- Engineering: Service data travel over Acyclic communication channels: SDOs in CANopen, record data in PROFINET, explicit messages in EtherNet/IP, ISDU in IO-Link.
- Commissioning: Parameter sets are often downloaded as service data at startup. Storing them centrally (in the controller or an IO-Link master) simplifies device replacement.
- Maintenance: Service data provide identification (serial number, firmware version), which feeds asset management and Configuration control.
- Documentation: The documentation team lists service data objects with index or address, data type, access rights, unit, default and range, and marks parameters whose change affects safety or requires a restart.
Service data vs. process data
Process data are exchanged cyclically and must arrive on time; service data are exchanged occasionally and may take longer. Putting parameters into cyclic data wastes bandwidth; polling process values via service channels misses timing.