Glossary · Engineering, integration and validation
I/O list
Also known as: Input/output list, IO list
German: E/A-Liste
In automation engineering, an I/O list is a table of all input and output signals connected to a control system, typically with tag number, description, signal type, range, engineering unit and assigned controller channel. It links the process design, electrical design and control software.
- Validation
In one sentence
An I/O list tables all input and output signals of a control system with tag, description, signal type, range and assigned channel.
Example
In the I/O list, TT-204 is a 4–20 mA input for 0–150 °C on rack 2, slot 5, channel 3.
How it applies
- Engineering: The I/O list is derived from the Piping and instrumentation diagram (P&ID) or machine design and drives controller sizing, the Hardware configuration and the Electrical schematic.
- Commissioning: Loop checks go through the I/O list signal by signal to confirm wiring, scaling and software assignment.
- Maintenance: Technicians use it to locate a signal quickly from the tag number to the terminal and controller channel.
- Documentation: The documentation team uses the I/O list as a consistent source for tag names and units in manuals and keeps a reference to the list revision, since I/O lists change often during projects.
I/O list vs. signal list
An I/O list covers physical inputs and outputs wired to the control system. A Signal list is usually broader and also includes signals exchanged over networks and interfaces with other systems. Some projects use the terms interchangeably; the project should define them.