The Q4C is a multi-channel controller display and alarm unit that utilizes digital communications to interface with a maximum of four remote digital QEL transmitter/ sensors.These are used to measure a wide variety of toxic gases such as CO, NO2, NH3, HS2, SO2, refrigerants, and com- bustibles. The RS-485 communication is connected via a 4-wire multidrop daisy chain configuration to reduce the overall installation costs of the system. Alarm setpoints are set through the front keypad or through QEL-supplied software that is downloaded to the controller from a PC or laptop computer. Common relay configurations include voting, averaging, delay on actuation and de-actuation, normally or not-normally energized and latching.The audible alarm has three buzzer settings, continuous, intermittent and double-tap intermittent. An additional feature includes 24 VDC transistor outputs for a horn and strobe.
