3-14 B90 Low Impedance Bus Differential System GE Multilin3.2 WIRING 3 HARDWARE3Figure 3–14: CT/VT MODULE WIRING3.2.5 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 may 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 B90 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 is used.The four inputs per common allows for high-density inputs in combination with outputs, with a compromise of four inputssharing one common. If the inputs must be isolated per row, then two inputs per common return should be selected (4Dmodule).The tables and diagrams on the following pages illustrate the module types (6A, etc.) and contact arrangements that maybe ordered for the relay. Since an entire row is used for a single contact output, the name is assigned using the module slotposition and row number. However, since there are two contact inputs per row, these names are assigned by module slotposition, 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 is open,and the DC current through the output contact when it is closed. Each of the monitors contains a level detector whose out-put is set to logic “On = 1” when the current in the circuit is above the threshold setting. The voltage monitor is set to “On =1” when the current is above about 1 to 2.5 mA, and the current monitor is set to “On = 1” when the current exceeds about80 to 100 mA. The voltage monitor is intended to check the health of the overall trip circuit, and the current monitor can beused to seal-in the output contact until an external contact has interrupted current flow.Block diagrams are shown below for form-A and solid-state relay outputs with optional voltage monitor, optional currentmonitor, and with no monitoring. The actual values shown for contact output 1 are the same for all contact outputs.~~~~~~~~~~~~~~~~~~~~1a1b1c2a2b2c3a4a5a6a7a8a3b4b5c6c7c8c3c4cCurrent inputs8F and 8L modules (4 CTs and 4 VTs)Voltage inputsVAVBVCVXVAVBVCVXIAICIBIGIA5IC5IB5IG5IA1IC1IB1IG1~~~~~~~~~~~~~~~~~~~~~~~~1a5a1b5b1c5c2a6a2b6b2c6c3a7a4a8a3b7b4b8b3c7c4c8cCurrent inputs8H and 8N modules (8 CTs)IAIAICICIBIBIGIGIA5IA5IC5IC5IB5IB5IG5IG5IA1IA1IC1IC1IB1IB1IG1IG1842803A1.CDRCurrent inputs8K and 8S modules (7 CTs and 1 VT)~~~~~~~~~~~~1a1b1c2a2b2c3a4a3b4b3c4cIAICIBIGIA5IC5IB5IG5IA1IC1IB1IG1~~~~~~~~~ 5a5b5c6a6b6c7a7b7cIAICIBIA5IC5IB5IA1IC1IB1~~ 8a8cVVVoltage
