Auxiliary Relay Outputs
The Keltron PET494 is a PET400 series distributed-multiplex, compatible output control device. The PET494 contains four independent form "C" programmable dry relay contact circuits for the control of auxiliary devices such as horns, door holders, fan dampers, and elevator controls. Relay activation is driven by control-by-event software from the Keltron DMP/PLM703. The relays can be activated upon status changes of monitored points anywhere in the distributed-multiplex system. Each relay has a three-position - on-auto-off - toggle switch to enable manual relay control. Each relay has an individual red LED to indicate relay energization and a yellow LED to indicate that the relay is disconnected (off) by the manual switch, or because of a relay coil fault. Manual relay activations are only printed and displayed on the DMP/PLM703; acknowledgement is not required.
On each PET494 control board there are three diagnostic LEDs indicating the following: power, on, transmitting, and receiving. To conserve power, these LEDs may be deactivated until needed.
The PET494 relay contacts are rated at 10 Amps, 30 VDC/250 VAC (resistive). Coils are supervised when de-energized. The contacts are not supervised. The PET494 control board provides 3 terminal block positions for connection of field wiring to each relay. These allow access to the normally closed (NC) contact, the normally open (NO) contact, and the common terminal. The NC/NO designations apply to the normal (de-energized) state.
The relay contact circuits are non-power-limited and must be separated by 0.25" from all power-limited circuits. Per NFPA 72, auxiliary relays must be located within 3 feet of the controlled circuit or device with the interconnecting wiring in conduct.
Modes of operation PET output control circuits may be programmed for three different modes of operation. In addition, for each mode, a programmable activation delay time from 1 to 9999 seconds may be selected:
| MODE W | Outputs are activated when an event of the programmed level is received, and are automatically cleared after a programmable time period from 1 to 9999 seconds. The default time period is 30 seconds. |
| MODE X | Outputs are activated upon occurrence of the programmed event on the specific input is received, and are cleared upon acknowledgement. |
| MODE Y | Outputs are activated when an event of the programmed level is received, and are cleared for any other event on the specified input. Outputs cannot be activated for restore to normal events. |
Each PET494 includes two RS485 distributed-multiplex communication ports. In a bus configuration (Class B), one port can be used for branching enabling a "fresh start" to another group of units for longer distance coverage. Alternatively, the two ports allow use of a ring configuration for true Class A operation up to and including NFPA 72, STYLE 7, SLC performance. The PET494 follows all PET400 series distributed-multiplex rules for communication distances, termination, branching, and addressing, and may be mixed and matched on the same 400 series wiring scheme with other PET400 series transceivers and output control devices. Distributed-multiplex communications to the PET494 are supervised and faults are annunciated in a similar way to other PET400 transceivers. Each PET494 requires a unique address on the distributed-multiplex and counts toward the limit of total wiring scheme capacity.
Power options
PET494DC - power applied to the PET494DC can be from 10.8 volts to 25 volts DC filtered (0.5vpp ripple). Current drain is 80 to 85ma with 85ma being drawn when the diagnostic LEDs are on.
PET494IDC - the IDC unit adds isolation to the PET power input. Power applied at the input can be from 17.6 to 25VDC filtered and the current drain is 100ma. The added isolation permits powering a PET494 from an FACP or multiple PET494IDC units from a common DC power source while maintaining the isolation of the DC power source from the wiring scheme.
PET494AC - The PET494AC unit is virtually the same as the PET494DC, using the same control pc board, but with an added isolating AC power source, the PETPS. Input power must be 120VAC at 0.05A. A 2 A-hr battery must be utilized for 24-hour standby. AC powered models report AC fail and low/no battery.
Power wiring - DC, IDC - the PET494DC and PET494IDC use identical power wiring. All power wiring is power limited and must be powered by a Class 2 or Class 3 power limited power source listed for fire protective signaling use.
Power wiring - AC - the 120VAC input is non power limited and must be segregated by at least 0.25" from all power limited wiring.
Installation
The PET494 may be installed in either of the two standard PET compatible, wall mount enclosures, the single position PETBX or the multi-position PETENC. These enclosures include correctly spaced standoffs for mounting the PET(s) and power supply and have sufficient room for the appropriate battery. The PETBX also provides conduit knockouts for field wiring connections.
The PET494 pc board measures 5.25" x 6.25".
The shipping weight is 1 lb. for DC and IDC models and 2 lbs. for the AC model. The PETBX shipping weight is 6 lbs.