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Communication protocols and networks
Communication protocols and networks
Codra has over twenty years' experience in developing protocols for all types of media: serial links, USB, wired and wireless IP, PSTN, GSM, GPRS, CPL, etc.
A few references:
- Radioprotection protocols: We have developed interfaces for communicating with devices from various vendors of radioprotection equipment through projects with organizations such as EDF, the IRSN, AFCN, and CEA:
- Saphymo (Aquascan, Portals, etc.)
- Mirion (NGM209M, ABPM203M, IM 201M, etc.)
- Technidata (Envilog, Sara, etc.)
- Bitt technology (Teleray)
- Low-Level Interface Protocol (PIE-BN): We developed a custom protocol for communications between various SCADA systems for the Laser MégaJoule project. PIE-BN was designed to:
- Offer an end-to-end object interface
- Ensure interoperability (Unix-Windows & .NET-Java)
- Include session and redundancy mechanisms
- Integrate mechanisms to notify changes in values, based on those available in OPC
- Enable calls to remote methods
This protocol is the cornerstone enabling “secure” communications between various SCADA systems.
PIE-BN was developed under .NET and Java and uses Web services.
- OPC UA interface: Since 1997 we have developed on average between 5 and 10 OPC servers.
Codra has developed OPC UA servers for various customers since 2011. As with OPC, we started with a foundation toolkit and then made it more robust.
- SYMPHONIE driver – RATP: This driver interfaces the application kernel with application-level objects of the RATP's SYMPHONIE control system, based on APPLIBUS object middleware. Applications view a SYMPHONIE object as a device: there is a device type for each object type implemented in SYMPHONIE.
- CMLNET protocol – COGEMA The Hague: This protocol, developed for COGEMA The Hague, uses the OSI data link layer (layer 2) in order to recognize machines and the transport layer (layer 4) for data transfer. Initially it enabled the Software Maintenance Center (CML) to periodically check that the applications loaded in the various acquisition and control devices had not been modified. Its use was subsequently expanded to cover communications between data acquisition systems and storage and supervision systems.
- APRILNet protocol: This proprietary protocol, developed as a driver, was implemented on APRIL PLCs in order to exchange process variables. It is an application-level protocol (OSI layer 7) using ISO-TP4 services (OSI layer 4). The data transported via this protocol is encoded using Abstract Syntax Notation (ASN1), standardized by ISO. An ASN1 encoder/decoder was developed for the project.
- MMS protocol - RATP: Manufacturing Messaging Service (MMS) is one of the application-level protocols (OSI layer 7) standardized by the ISO. It allows developers to connect control systems (CIM level 2) to PLCs (CIM level 1). The protocol was developed as a Panorama driver to connect SCADA systems to controllers supporting MMS (SIEMENS and TELEMECANIQUE). We used the OSI-TP4 transport layer provided in standard with Windows NT, and we developed layers 5, 6, and 7 specifically for this project. The data transported for this protocol is also encoded in ASN1 (as with APRILNet). We used and extended the encoder developed for APRILNet.
- Serial port protocols: Codra has developed several protocols to communicate with industrial equipment connected to mainframes over synchronous or asynchronous serial links. This equipment includes:
- PLCs connected via Jbus links (Jbus is a subset of Modbus)
- MICRO-Z equipment from Controle Bailey/Yokogawa
- Fire detection systems (CERBERUS)
- Control systems for electrical equipment, using a “simplified master-master“ protocol
- Measuring devices connected over 1 Mbps HDLC links
Most of these protocols are installed on intelligent couplers (in Intel Multibus I or II format).