SMP Gateway User Manual • 9
2.1.3 SMP Gateway Internals
The SMP Gateway's internal architecture is based on a series of software components called
protocol components. Slave protocol components implement all the functions necessary to
process requests received from a SCADA or control center. Master protocol components
implement the functions necessary to poll devices and send control requests. Cooper Power
Systems provides components for most standard protocols, such as DNP3, MODBUS, IEC-60870-
5-101/103/104 and IEC 61850, as well as a large number of proprietary protocols such as SEL,
ABB TEN BYTE, Motorola MDAC, and more.
The master protocol component polls the device and stores the data that it retrieves in an internal
database, called the Real-Time Data Exchange (RTDX). The RTDX is much more than a simple
data store. Besides storing the current value of all the device data points, it also stores the different
types of information than can be provided by a substation device, such as the quality and
timestamp of the data. It also stores information such as device tags used for control functions.
REAL-TIME
DATA EXCHANGE
SLAVE
PROTOCOL
MASTER
PROTOCOL
SCADA
DEVICE
Figure 3 The SMP Gateway real-time data exchange
2.1.4 Communications Components
SMP Gateway protocol components process the messages exchanged among the control centers
and the devices. However, these messages can be transmitted using various communications
methods. For instance, the MODBUS protocol can be used on a TCP/IP network or on an RS-232
serial link.
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