OCIT Outstations
OCIT Outstations interfaces use the Internet technology
OCIT Outstations interfaces use the Internet technology. They connect traffic controllers with central devices. Their task is the safe supply, the operation and monitoring of the device. This requires an immediate acknowledgement or error handling. Special meaning has therefore the transmission protocol BTPPL developed for OCIT Outstations
Communication model
With OCIT Outstations a universally applicable interface was created, which is not fixed on a certain communication medium. The communication media comprises older range limited 2-wire lines, radio communications, Ethernet and Internet. The data communication based on standards of the telecommunications technology and can use all usual media and telecommunication services, which are tied up by the layers 2 and 1. In OCIT-O for it so-called Profiles are defined. Transitions between different transmitting media, telecommunication services and topologies are possible.
Traffic controllers with OCIT-O interfaces must control complex traffic dependence locally and seize and process traffic measured values.
Time performance
OCIT systems with OCIT Outstations interfaces transfer instructions and data only with the arrival of certain events. The synchronization of all devices in the system is made by exact clocks (radio clock or time service of the central device).
Protocols
The data communication uses the ISO standard OSI Layers.
OSI layers of the transmission profile for point-to-point connections
The OCIT Outstations protocol is the transmission protocols of the user level. It covers the integration of the OCIT Outstations functions into the equipment software and the optimized protocol BTPPL. With exception of the OCIT Outstations protocol BTPPL only standard protocols are used. TCP/UDP/IP are transportation protocols of the middle levels. (* The use of the UDP protocol is no longer recommended.)
Characteristics of BTPPL
Substantially smaller data overhead and shorter transmission times. Therefore still existing old 2-wire lines with bad transmission quality can be used. A firm component is the SHA-1-Algorithmus, which ensures by password protection a high transmission reliability by 24-bit-Codierung, so that hackers cannot manipulate the field devices.
Functions and objects
All executable functions must be implemented by conformal devices in same way, in order to ensure a uniform system function. The exact specification of the objects takes place in the OCIT documents. The pertinent data definitions use the data description language XML (Extensible Markup Language). They are the basis for the implementation in the field devices. OCIT Outstations objects are fixed in the documents OCIT-O Basis and OCIT-O Lstg. They represent the standard.
Member Numbers
With the help of the Member Nummbers a distinction between standard OCIT objects and the definitions of the manufacturers (manufacturer objects) is possible in the OCIT system.
List of member numbers