5-124 B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUALPRODUCT SETUP CHAPTER 5: SETTINGS5Figure 5-56: Input and output extension via direct inputs and outputsIn this application, apply the following settings. For UR-series IED 1:DIRECT OUTPUT DEVICE ID: “1”DIRECT I/O CH1 RING CONFIGURATION: “Yes”DIRECT I/O DATA RATE: “128 kbps”For UR-series IED 2:DIRECT OUTPUT DEVICE ID: “2”DIRECT I/O CH1 RING CONFIGURATION: “Yes”DIRECT I/O DATA RATE: “128 kbps”The message delivery time is about 0.2 of power cycle in both ways (at 128 kbps); that is, from device 1 to device 2, andfrom device 2 to device 1. Different communications cards can be selected by the user for this back-to-back connection(for example: fiber, G.703, or RS422).Example 2: Interlocking busbar protectionA simple interlocking busbar protection scheme could be accomplished by sending a blocking signal from downstreamdevices, say 2, 3, and 4, to the upstream device that monitors a single incomer of the busbar, as shown.Figure 5-57: Sample interlocking busbar protection schemeFor increased reliability, a dual-ring configuration (shown as follows) is recommended for this application.
