Glossary · Sensors and measurement
Sensor/actuator level
Also known as: Field level, Level 0 (automation pyramid)
German: Sensor-Aktor-Ebene
In the automation pyramid, the sensor/actuator level is the lowest level, where sensors measure the process and actuators act on it; it corresponds roughly to level 0 and the device side of level 1 in the functional hierarchy of IEC 62264-1 (ISA-95).
- Sensors
- Standards
In one sentence
The sensor/actuator level is the lowest level of the automation pyramid, where sensors measure and actuators act on the physical process.
Example
At the sensor/actuator level of a bottling line, proximity sensors, valve terminals and drives are connected to the PLC via IO-Link and a fieldbus.
How it applies
- Engineering: Devices at this level connect through discrete I/O, analog signals, IO-Link, AS-Interface or fieldbuses. Increasingly, smart devices also provide diagnostics and parameters to higher levels directly.
- Security: Field devices are often the least protected components. IEC 62443 zone and conduit models treat them as part of the control network, which must be protected by segmentation.
- Architecture: The pyramid model is a simplification; modern architectures also pass data from field devices to edge or cloud systems. The levels still help assign responsibilities.
- Documentation: System descriptions should show which devices sit at which level and how data flows upward. This helps readers understand where a value originates.
Sensor/actuator level vs. field level
Many sources use field level for the same layer. Some models separate a sensor/actuator level below the field level, where fieldbus devices and remote I/O sit. State which model a document uses.