Contact Inputs And Outputs - GE L60 Instruction Manual

WIRING CHAPTER 3: INSTALLATION
The L60 uses a special CT/VT module not available on other UR-series relays. This type 8P module has four current inputs
and special communications inputs/outputs for interfacing with PLCs. The communications interface requires an external
DC source (station battery) to drive inputs/outputs as shown in the L60 Channel Communications section in this chapter.
Substitute the tilde "~" symbol with the slot position of the module in the following figure.
Figure 3-11: CT/VT module wiring
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3.3.5 Contact inputs and outputs

Every contact input/output module has 24 terminal connections. They are arranged as three terminals per row, with eight
rows 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-A
output, 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 input/output modules have two versions of grouping: four
inputs per common return and two inputs per common return. When a contact input/output module is ordered, four inputs
per common is used. 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 that
can be ordered for the relay. Since an entire row is used for a single contact output, the name is assigned using the module
slot position and row number. However, since there are two contact inputs per row, these names are assigned by module
slot 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 is
open, and the DC current through the output contact when it is closed. Each of the monitors contains a level detector
whose output 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 there is a voltage across open contact (the detector allows a current of about 1 to 2.5 mA), and the
current monitor is set to "On = 1" when the current flowing through the closed contact exceeds about 80 to 100 mA. The
voltage monitor is intended to check the health of the overall trip circuit, and the current monitor can be used to seal-in
the output contact until an external contact has interrupted current flow. If enabled, the current monitoring can be used as
a seal-in signal to ensure that the form-A contact does not attempt to break the energized inductive coil circuit and weld
the output contacts.
3-12 L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL