CHAPTER 3: INSTALLATION WIRINGN60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL 3-933.3.5 Process bus modulesThe N60 can be ordered with a process bus interface module. The module interfaces with the HardFiber Process BusSystem, or HardFiber Brick, allowing bidirectional IEC 61850 fiber optic communications with up to eight HardFiber Bricks.The HardFiber system integrates seamlessly with the existing UR-series applications, including protection functions,FlexLogic, metering, and communications.This process bus system offers the following benefits:• Reduces labor associated with design, installation, and testing of protection and control applications using the UR byreducing the number of individual copper terminations• Integrates seamlessly with existing UR applications, since the IEC 61850 process bus interface module replaces thetraditional CT/VT modules• Communicates using open standard IEC 61850 messagingFor details on the HardFiber system, see its Instruction Manual.3.3.6 Contact inputs and outputsEvery contact input/output module has 24 terminal connections. They are arranged as three terminals per row, with eightrows in total. A given row of three terminals can be used for the outputs of one relay. For example, for form-C relay outputs,the terminals connect to the normally open (NO), normally closed (NC), and common contacts of the relay. For a form-Aoutput, there are options of using current or voltage detection for feature supervision, depending on the module ordered.The terminal configuration for contact inputs is different for the two applications.The contact inputs are grouped with a common return. The N60 has two versions of grouping: four inputs per commonreturn and two inputs per common return. When a contact input/output module is ordered, four inputs per common isused. If the inputs must be isolated per row, then two inputs per common return are selected (4D module).The tables and diagrams on the following pages illustrate the module types (6A and so on) and contact arrangements thatcan be ordered for the relay. Since an entire row is used for a single contact output, the name is assigned using the moduleslot position and row number. However, since there are two contact inputs per row, these names are assigned by moduleslot position, row number, and column position.Some form-A / solid-state relay outputs include circuits to monitor the DC voltage across the output contact when it isopen, and the DC current through the output contact when it is closed. Each of the monitors contains a level detectorwhose output is set to logic “On = 1” when the current in the circuit is above the threshold setting. The voltage monitor isset to “On = 1” when there is a voltage across open contact (the detector allows a current of about 1 to 2.5 mA), and thecurrent monitor is set to “On = 1” when the current flowing through the closed contact exceeds about 80 to 100 mA. Thevoltage monitor is intended to check the health of the overall trip circuit, and the current monitor can be used to seal-inthe output contact until an external contact has interrupted current flow. If enabled, the current monitoring can be used asa seal-in signal to ensure that the form-A contact does not attempt to break the energized inductive coil circuit and weldthe output contacts.Block diagrams are shown as follows for form-A and solid-state relay outputs with optional voltage monitor, optionalcurrent monitor, and with no monitoring. The actual values shown for contact output 1 are the same for all contactoutputs. Form-A contact output with or without a current or voltage monitoring option is not polarity sensitive. The polarityshown in the figure is required for solid-state contact output connection.