5-342 F60 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUALINPUTS/OUTPUTS CHAPTER 5: SETTINGS5For example, the trip circuit current is monitored by providing a current threshold detector in series with some Form-Acontacts (see the trip circuit example in the Digital Elements section). The monitor sets a flag (see the specifications forForm-A). The name of the FlexLogic operand set by the monitor, consists of the output relay designation, followed by thename of the flag; for example, Cont OP 1 IOn.In most breaker control circuits, the trip coil is connected in series with a breaker auxiliary contact used to interrupt currentflow after the breaker has tripped, to prevent damage to the less robust initiating contact. This can be done by monitoringan auxiliary contact on the breaker which opens when the breaker has tripped, but this scheme is subject to incorrectoperation caused by differences in timing between breaker auxiliary contact change-of-state and interruption of current inthe trip circuit. The most dependable protection of the initiating contact is provided by directly measuring current in thetripping circuit, and using this parameter to control resetting of the initiating relay. This scheme is often called trip seal-in.This can be realized using the Cont OP 1 IOn FlexLogic operand to seal-in the contact output as follows:CONTACT OUTPUT H1 ID: “Cont Op 1"OUTPUT H1 OPERATE: any suitable FlexLogic operandOUTPUT H1 SEAL-IN: “Cont Op 1 IOn”CONTACT OUTPUT H1 EVENTS: “Enabled”Figure 5-189: Contact input/output module type 6A contact 1 logic5.10.3.2 Latching outputsSETTINGS INPUTS/OUTPUTS CONTACT OUTPUTS CONTACT OUTPUT H1aThe latching output contacts are mechanically bi-stable and controlled by two separate (open and close) coils. As suchthey retain their position even if the relay is not powered up. The relay recognizes all latching output contact cards andpopulates the setting menu accordingly. On power up, the relay reads positions of the latching contacts from the hardwarebefore executing any other functions of the relay (such as protection and control features or FlexLogic).The latching output modules, either as a part of the relay or as individual modules, are shipped from the factory with alllatching contacts opened. It is highly recommended to double-check the programming and positions of the latchingcontacts when replacing a module.Since the relay asserts the output contact and reads back its position, it is possible to incorporate self-monitoringcapabilities for the latching outputs. If any latching outputs exhibits a discrepancy, the LATCHING OUTPUT ERROR self-testerror is declared. The error is signaled by the LATCHING OUT ERROR FlexLogic operand, event, and target message. CONTACT OUTPUT H1a OUTPUT H1a IDL-Cont Op 1Range: up to 20 alphanumeric characters OUTPUT H1a OPERATE:OffRange: FlexLogic operand OUTPUT H1a RESET:OffRange: FlexLogic operand OUTPUT H1a TYPE:Operate-dominantRange: Operate-dominant, Reset-dominant OUTPUT H1a EVENTS:DisabledRange: Disabled, Enabled
