The SECS Definition Language (SDL) file is where SECS messages are defined. See also SECS/GEM.
The SECS/GEM (SEMI Equipment Communications Standard/Generic Equipment Model) is the semiconductor's equipment interface protocol for equipment-to-host data communications. Developed by the SEMI (Semiconductor Equipment and Materials International) organization, the standards define a common set of equipment behavior and communications capabilities. In Ignition, the SECS/GEM Module enables Ignition projects and third-party applications to communicate with semiconductor fab equipment.