ADA/SCADA RTU protocol based on the 3-layer UCA model
This paper describes an implementation of a DA/SCADA RTU communication protocol based on the 3-layer reference model for wide area networks specified in the Utility Communications Architecture (UCA) VL1.0. This protocol is based on the following international standards: EIA-232-D, High-level Data Link Control (HDLC) [ISO/IEC 3309], and Manufacturing Message Specification (MMS) [ISO/IEC 95061]. A description of the HDLC frame structure used in this implementation is provided. This includes a description of the extended transparency option for Start/Stop transmission, commonly referred to as {open_quotes}asynchronous HDLC{close_quotes}. This option allows for the transmission of HDLC frames using inexpensive asynchronous communication hardware. The data link topology described in this paper is an unbalanced, point-to-multipoint topology consisting of one primary, or, master station, and multiple secondary, or remote, stations. The data link operates in the Normal Response Mode (NRM). In this mode a secondary station may initiate transmissions only as a result of receiving explicit permission to do so from the primary station. The application layer protocol described in this paper is an implementation of the Manufacturing Message Specification (MMS). The MMS device model, or Virtual Manufacturing Device (VMD), for a DA/SCADA Remote Terminal Unit is provided. The current VMD model provides a view of common RTU data types, plus, A/C Input (ACI) data including phasor magnitude and mean readings, harmonics, and overcurrent alarm information.
- OSTI ID:
- 192209
- Report Number(s):
- CONF-9501113--
- Country of Publication:
- United States
- Language:
- English
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