February 5, Inputs and Output Relays

February 5, What are Inputs and Output Relays? Inputs allow the controller to receive signals from the outside world Output Relays allow the controller to turn on or off external devices

February 5, Input Definition A point on the controller which detects a state change generated by an outside device –Typically some kind of switch The controller then performs some action based on programmed instructions

February 5, Normally-Closed Input A normally-closed switch generates a state change by opening a normally-closed input circuit A typical normally-closed input application is a Door Status switch

February 5, Normally-Open Input A normally-open switch generates a state change by closing a normally-open input circuit A typical normally-open input application is a Request to Exit device

February 5, Input Types The PXL-500 can accept any of four programmed input signals: –Door Status –Request to Exit –General Purpose The controller responds to input signals according to programmed instructions

February 5, Door Status Input A normally-closed input, it reports the status of the door: open or closed –If the status is “forced open,” the controller can respond with a Door Forced alarm –If the status is “open too long,” the controller can respond with a Door Held Open alarm

February 5, Request to Exit (RTE) Input A normally-open input, it reports a user request to exit through a secure door –The controller can unlock a secure door to allow exit

February 5, Global Unlock Input A normally-open input, it reports a request to unlock all doors immediately –The controller can send a signal to all controllers to unlock all secure doors, allowing exit

February 5, General Purpose Inputs If you need General Purpose inputs, consider using an SB-593 Satellite Board

February 5, General Purpose Inputs Can be either normally- open or normally-closed inputs, an input reports a change of state –The controller must be programmed with instructions on how to respond to the state change

February 5, Output Relay Definition A point on the controller that changes state to initiate an action outside of the controller An output relay is driven by programming instructions within the controller

February 5, Output Relay Definition Keri controllers use Form C relays –Single-pull, double-throw (SPDT) –Drive either normally-open and normally-closed circuits –Energizing the coil toggles the relay common from normally-closed to normally-open

February 5, Output Types The PXL-500 can output a state change to any of two programmed output types –Door Lock Relay –Alarm Relay An optional SB-593 Satellite Board adds other output types –Door Held Open Relay –General Purpose Relay

February 5, Door Lock Relay Unlocks a door when activated Can use either the normally-closed or normally-open output circuits –depends upon the level of safety versus security: Fail-safe versus Fail-secure

February 5, Fail-safe Lock Application Requires power to keep doors locked, doors are unlocked if the power fails Typically uses a normally-closed circuit with magnetic door locks for operation When the relay is activated: –The normally-closed circuit is opened –Power to the door lock is dropped –The door can now be opened

February 5, Fail-safe Lock Circuit Since doors require power to be locked, if the power fails, doors are automatically unlocked Allows safe exit in power failure situations, but security may be compromised

February 5, Fail-secure Lock Application Requires power to unlock doors, doors are locked if power fails Typically uses the normally-open circuit for operation When the relay is activated: –The normally-open circuit is closed –Power is applied to the door lock –The door can now be opened

February 5, Fail-secure Lock Circuit Since doors require power to be unlocked, if the power fails, doors cannot be unlocked Provides security in power failure situations, but safety may be compromised

February 5, Alarm Relay Used to activate an alarm when a door’s security is violated Typically uses the normally-open output circuit –when the relay is activated, the normally- open circuit is closed –closing the circuit allows an alarm to sound

February 5, Additional Relay Outputs Available on the SB-593 Satellite Board

February 5, Door Held Open/Door Forced Relays Activates an alarm when –A door is held open past a defined time –A door is forced open Typically a normally- open output circuit, when activated, the normally- open circuit is closed, providing power to sound an alarm

February 5, General Purpose Relays Either normally-open or normally-closed output circuits can be used External equipment that will respond to the state change is connected to the relay output The controller is then programmed with instructions on when to generate a general purpose relay state change