What is BS EN 61131-9 - Single-drop digital communication interface for small sensors and actuators (SDCI) about?
BS EN 61131-9 is the ninth part of the multiple series that specifies a single-drop digital communication interface technology for small sensors and actuators SDCI (commonly known as IO-Linkâ„¢2), which extends the traditional digital input and digital output interfaces as defined in IEC 61131-2 towards a point-to-point communication link. This technology enables the transfer of parameters to Devices and the delivery of diagnostic information from the Devices to the automation system.
Note: BS EN 61131-9 does not cover communication interfaces or systems incorporating multiple points or multiple drop linkages, or integration of SDCI into higher-level systems such as field buses.
Who is BS EN 61131-9 - Single-drop digital communication interface for small sensors and actuators (SDCI) for?
BS EN 61131-9 on programmable controllers is useful for:
- Software programmers/engineers  
- The IT industries 
- Users of programmable controller systems 
- Implementers of programming and debugging tools 
- Programming language implementers 
Why should you use BS EN 61131-9 - Single-drop digital communication interface for small sensors and actuators (SDCI)?
Any SDCI compliant Device can be attached to any available interface port of the Master. SDCI compliant Devices perform physical to digital conversion in the Device and then communicate the result directly in a standard format using "coded switching" of the 24 V I/O signaling line, thus removing the need for different DI, DO, AI, AO modules and a variety of cables.
BS EN 61131-9 specifies the SDCI communication services and protocol (physical layer, data link layer, and application layer in accordance with the ISO/OSI reference model) for both SDCI Masters and Devices. BS EN 61131-9 specifies three different levels of diagnostic capabilities: immediate response by automated needs during the production phase, medium-term response by operator intervention, or longer-term commissioning and maintenance via extended diagnosis information.
Overall, BS EN 61131-9 defines a generic interface for connecting sensors and actuators to a Master unit, which may be combined with gateway capabilities to become a Fieldbus Remote I/O node.
