The D•420 Gas or Oxygen detector (electrochemical, semi-conductor or infrared) is intended for monitoring gas concentration levels in car parks, laboratories and refrigerated rooms. The list of the most important detectable gases are carbon monoxide CO or carbon dioxide CO₂, oxygen O₂, nitrogen dioxide NO₂, ammonia NH₃, sulphur dioxide SO₂, refrigerant gases (0-2000 ppm) and hydrogen sulphide H₂S (this list is not exhaustive).
It is intended to work in conjunction with a compatible control unit (U•V6 or U•C2). In a gas detection system, the alarm thresholds are predefined for each targeted gas at the U•V6 or U•C2 control unit. The number of alarm thresholds is defined by several alarm criteria, either threshold values or different calculation modes. The measurement rate is the full scale measurement value (% LEL, PPM, % v/v), i.e. the highest gas concentration that can be measured.
The measurement range selected on a particular channel of the U•V6 or U•C2 must correspond to that of the D•420.
The D•420 uses an electrochemical (2-wire), semi-conductor (3-wire) or infrared (3-wire) sensor whose signal is converted by the “D•BASE 420 board”, into an electrical signal with a current of 4 to 20 mA in accordance with the concentration of the explosive gas in the air. This electrical signal is transmitted to the U•V6 or U•C2 in a current loop.
The D•420 comes with a flame-retardant, dust and water proof (IP65) plastic housing (UL 94 V-0), a liquid crystal display (LCD) which, during normal operation, displays the gas concentration. It also comes with a three-key touch-sensitive keypad.
The D•420 also has an explosion-proof sensor head and a terminal block mounted on a printed circuit board. The sensor head is designed to facilitate eventual replacement of the sensor.
The D•420 Explosive or Toxic Gas detector is intended for use in commercial and light industrial buildings, laboratories and refrigerated rooms.
The operating temperature ranges* are:
