Direct Input And Output Communications; Description - GE B30 Instruction Manual

3.3 DIRECT INPUT AND OUTPUT COMMUNICATIONS

3.3DIRECT INPUT AND OUTPUT COMMUNICATIONS
The B30 direct inputs and outputs feature makes use of the type 7 series of communications modules. These modules are
also used by the L90 Line Differential Relay for inter-relay communications. The direct input and output feature uses the
communications channels provided by these modules to exchange digital state information between relays. This feature is
available on all UR-series relay models except for the L90 Line Differential relay.
The communications channels are normally connected in a ring configuration as shown below. The transmitter of one mod-
ule is connected to the receiver of the next module. The transmitter of this second module is then connected to the receiver
of the next module in the ring. This is continued to form a communications ring. The figure below illustrates a ring of four
UR-series relays with the following connections: UR1-Tx to UR2-Rx, UR2-Tx to UR3-Rx, UR3-Tx to UR4-Rx, and UR4-Tx
to UR1-Rx. A maximum of 16 URs can be connected in a single ring
3
Figure 3–31: DIRECT INPUT AND OUTPUT SINGLE CHANNEL CONNECTION
IRC modules with protocol C37.94 and G.703 are designed for back-to-back communication connections, so the ring con-
figuration shown in the previous figure does not apply. To establish inter-relay communication in more than two URs, you
need to have two channel IRC module and enable DIRECT I/O CHANNEL CROSSOVER function in all relays, as shown in
the next figure. This configuration can be expanded to 16 URs, and this configuration does not provide redundancy ring
since both channels are made into single ring by the channel crossover function. As per the figure Typical Pin Interconnec-
tion between Two G.703 Interfaces later in this chapter, the clock is supplied typically by multiplexer (MUX) and all URs are
in Loop Timing Mode. If there is no MUX, then UR1 and UR3 can be in Internal Timing Mode and UR2 and UR4 can be in
Loop Timing Mode. That is, connected channels must have opposite timing modes.
Figure 3–32: RING CONFIGURATION FOR C37.94 MODULE (CONCEPT ALSO APPLIES TO G.703)
3-32
Tx
UR #1
Rx
Tx
UR #2
Rx
Tx
UR #3
Rx
Tx
UR #4
Rx
842006A1.CDR
B30 Bus Differential System
3 HARDWARE

3.3.1 DESCRIPTION

GE Multilin