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QAS - 200 SERIES DUAL CHANNEL CONTROLLERS

The QAS - 200 Series Dual Channel Controller is a microprocessor based unit that  monitors input signals and provides relay outputs for alarm and control. The units are switch selectable for either 4-20 mA DC input (standard) or broad spectrum solid state sensor inputs for hazardous gas detection. Solid state sensor inputs for hazardous gas detection. Solid state sensors can be either integrally or remote mounted to the 115 VAC powered electronics encased in a Nema 4X surface mount enclosure. Temperature compensation for solid state sensors is field selectable. Two DPDT relays are provided, which can be configured to operate in common to both channels or independently assigned. Relay time delays, both on and off, and fail safe operation are field configurable. LED status indicator lights provide alarm and sensor information for each channel. Optional digital LED display(s) provide indication of 4-20 mA DC inputs (only) in engineering units.

INPUT ONE AND TWO SELECTION TABLE

Enlarge Picture

Standard           Calibration  
INPUT TYPE # LOW ALARM HI ALARM
4 to 20 mA DC1 01 7.2 mAmp (20%) 10.4 mAmp (40%)
Solid State Sensor1 02 No Calibration
Carbon Monoxide2 16 50 ppm in VE 100 ppm in VE
Combustibles3 17 10% LEL 20% LEL
Ammonia 22 35 ppm 300 ppm
Freon R11 26 500 ppm 1000 ppm
Freon R12 27 500 ppm 1000 ppm
Freon R22 28 500 ppm 1000 ppm
Freon R134a 30 500 ppm 1000 ppm
1 - Sensor not included
2 - Measured in vehicle exhaust
3 - Calibrated for Propane

 

PRINCIPLE OF OPERATION

The unit is configured using DIP switches. These switches configure channel input types, relay configurations, audible alarm and fail action. If the optional digital display(s) are ordered for 4-20 mA inputs, additional DIP switches are provided for configuring control action, adjusting the deadband and setpoints. Non-acceptable settings will be indicated by the LED fault indication light. Units are fully tested and calibrated as ordered when shipped from the factory. Input signal(s) are monitored by the microprocessor and compared to the relay actuation setpoints. If the setpoint is reached or exceeded then the appropriate relay is actuated. When the signal drops below the setpoint factory hysteresis of 12.5%, the relay is deactivated. If the signal drops below or rises above the preset limits then the built-in test will cause the audible alarm to sound (if selected), the relays to energize (if selected) and the visual fault LED to illuminate.

Calibration is recommended on an annual basis. If the channel input type is solid state gas sensor, apply calibration gas to sensor and wait for stable signal before toggling setpoint one and/or setpoint two as required. If the channel input type is 4-20 mA DC then calibration is performed by inserting test leads into meter jacks and adjusting the potentiometer to desired setpoint value. Once this is achieved, toggle setpoint one DIP switch to lock setting to the EEPROM. Repeat for setpoint two using setpoint two DIP switch.

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Last Updated 03/18/10