Chapter 18 - Communications
The products supports a wide range of protocols to make them applicable to many industries and applications.
The exact data protocols supported by a particular product depend on its chosen application, but the following
table gives a list of the data protocols that are typically available.
SCADA data protocols
K-Bus, RS232, RS485, Ethernet
The relationship of these protocols to the lower level physical layer protocols are as follows:
Data Link Layer
This section should provide sufficient detail to enable understanding of the Courier protocol at a level required by
most users. For situations where the level of information contained in this manual is insufficient, further
publications (R6511 and R6512) containing in-depth details about the protocol and its use, are available on
Courier is an General Electric proprietary communication protocol. Courier uses a standard set of commands to
access a database of settings and data in the IED. This allows a master to communicate with a number of slave
devices. The application-specific elements are contained in the database rather than in the commands used to
interrogate it, meaning that the master station does not need to be preconfigured. Courier also provides a
sequence of event (SOE) and disturbance record extraction mechanism.
PHYSICAL CONNECTION AND LINK LAYER
Courier can be used with three physical layer protocols: K-Bus, EIA(RS)232 or EIA(RS)485.
Several connection options are available for Courier
The front serial RS232 port (for connection to Settings application software on, for example, a laptop
Rear Port 1 (RP1) - for permanent SCADA connection via RS485 or K-Bus
Optional fibre port (RP1 in slot A) - for permanent SCADA connection via optical fibre
Optional Rear Port 2 (RP2) - for permanent SCADA connection via RS485, K-Bus, or RS232
For either of the rear ports, both the IED address and baud rate can be selected using the front panel menu or by
the settings application software.
Layer 1 protocol
Standard for SCADA communications developed by General Electric.
Standard for SCADA communications developed by Modicon.
IEC standard for SCADA communications
Standard for SCADA communications developed by Harris. Used mainly in
IEC standard for substation automation. Facilitates interoperability.
Copper or Optical Fibre