Definition:
A Site Integration Test (SIT) is a formal test performed at the plant site to verify the integrated operation of the digital and analog aspects of the control system, and other subsystems before startup.
The SIT confirms that field wiring, instrument configuration, control logic, and shutdown sequences work together correctly. SIT verifies not just communication, but also timing, diagnostics, and failure response across system boundaries.
The FAT/SAT/SIT are all per the excellent IEC 62381.
Key Points:
- Extends beyond individual device testing to end-to-end system validation.
- Can include elements of Factory Acceptance Test (FAT) and Site Acceptance Test (SAT) but focuses on integration and communication.
- Would be part of Validation under IEC 61511-1.
- Generally a procedure and report. The report is often heavily reviewed by auditors and regulators.
- Would occur after the Site Acceptance Test (SAT)
Example:
A SIT verifies that a pressure transmitter signal properly travels through the SIS logic solver and causes the correct shutdown valve to close under site conditions. It would verify that the SIS is interfacing correctly with the BPCS.
See Also: SAT, validation, BPCS
Cited Source:
- IEC 61511-1:2016, Clause 14.3.
- IEC 62381
- Method FS – Installation, Commissioning and Validation