What is BS EN 61131-5 - Programmable controllers - Communications about?
BS EN 61131-5 is the fifth part of the multiple series that specifies the communication aspects of a programmable controller. In particular, BS EN 61131-5 specifies the behaviour of the PC as it provides services on behalf of other devices and the services the PC application program can request from other devices.
Note 1: BS EN 61131-5 is not intended to specify how any device can communicate with any device using a PC as a router or gateway.
Note 2: The behaviour of the PC as a communication client and server is specified independent of the particular communication subsystem, but the communication functionality may be dependent on the capabilities of the communication subsystem used.
Who is BS EN 61131-5 - Programmable controllers - Communications for?
BS EN 61131-5 on programmable controllers for communication 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 61131-5 - Programmable controllers - Communications?
Program verification is the testing of a PC application program to verify that it performs the function(s) it was designed to do in the process environment.
BS EN 61131-5 specifies the mapping of the PC communication functions to the MMS objects and services defined in ISO/IEC 9506-1 and extensions defined in ISO/IEC 9506-5. BS EN 61131-5 provides detailed status information about the PC and its subsystems via MMS Named Variables or MMS Unnamed Variables or both. BS EN 61131-5 specifies the behaviour of a PC when it is communicating in the abstract syntax.
Overall, BS EN 61131-5 provides you with the viewpoint of a PC how any device can communicate with a PC as a server and how a PC can communicate with any device.
