3-22 N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUALDIRECT INPUT AND OUTPUT COMMUNICATIONS CHAPTER 3: INSTALLATION3The communications channels are normally connected in a ring configuration, as shown in the following figure. Thetransmitter of one module is connected to the receiver of the next module. The transmitter of this second module is thenconnected to the receiver of the next module in the ring. This is continued to form a communications ring. The figureillustrates a ring of four UR-series relays with the following connections: UR1-Tx to UR2-Rx, UR2-Tx to UR3-Rx, UR3-Tx toUR4-Rx, and UR4-Tx to UR1-Rx. A maximum of 16 UR-series relays can be connected in a single ring.Figure 3-21: Direct input and output single-channel connectionThe interconnection for dual-channel type 7 communications modules is shown as follows. Two-channel modules allow fora redundant ring configuration. That is, two rings can be created to provide an additional independent data path. Therequired connections are: UR1-Tx1 to UR2-Rx1, UR2-Tx1 to UR3-Rx1, UR3-Tx1 to UR4-Rx1, and UR4-Tx1 to UR1-Rx1 for thefirst ring; and UR1-Tx2 to UR4-Rx2, UR4-Tx2 to UR3-Rx2, UR3-Tx2 to UR2-Rx2, and UR2-Tx2 to UR1-Rx2 for the second ring.Figure 3-22: Direct input and output dual-channel connection842006A2.CDRTxTxTxTxUR 1UR 2UR 3UR 4RxRxRxRx842007A3.CDRTx1UR 1Tx2Rx1Rx2Tx1UR 2Tx2Rx1Rx2Tx1UR 3Tx2Rx1Rx2Tx1UR 4Tx2Rx1Rx2
