Glossary · Automation fundamentals, platforms and components
Offset
Also known as: Zero offset, Address offset
German: Offset
In automation, an offset is a constant displacement from a reference: in measurement and control, a constant deviation of a signal or controlled variable from its true or desired value; in addressing, the distance of a data element from the start of a memory area or data block.
- Automation components
In one sentence
An offset is a constant displacement from a reference, such as a signal's zero error or a data element's address within a data block.
Example
A pressure sensor shows 0.05 bar with the line vented; this zero offset is corrected during calibration.
How it applies
- Measurement: Zero offsets are corrected by calibration or adjustment; a changing offset over time indicates Sensor drift.
- Control: A steady-state offset remains with purely proportional control; integral action removes it.
- Programming: Data block offsets define where values sit in memory; they matter when data is accessed absolutely or exchanged with other systems.
- Documentation: Specify which meaning applies. Interface descriptions should give offsets in bytes and bits; calibration documents should record measured and corrected offsets.
Offset vs. drift
An offset is a constant displacement. Drift is a slow change over time, which may show up as a growing offset. Robotics and CNC also use offsets for tool and work coordinates; see Coordinate system (robotics).