C12-17 Combustible Gas Transmitter

Brand: Analytical Technology Inc

ATI's C12-17 Combustible Gas Transmitter is a stand-alone gas transmitter designed to detect potentially hazardous concentrations of combustible gases in ambient air. 

Gases and hydrocarbon vapors such as methane, propane, butane, gasoline, toluene, hydrogen, and many others can be reliably monitored in process buildings, analyzer enclosures, pump stations, and gas compressor stations. 

In fact, anywhere gases or vapors may build up to explosive levels can be readily monitored using this transmitter.

C12-17 Combustible Gas Transmitters are three-wire transmitters, operating from 24 Vdc power supplies and transmitting a 4-20 mA signal proportional to 0-100% LEL (Lower Explosive Limit) of a particular gas or vapor. 

The gas transmitter is available either as a blind transmitter or with integral LCD display that provides local indication of gas concentration visible through the glass window in the explosion-proof housing. 

Gas transmitter units supplied with the integral display also contain a single alarm set-point and relay for local alarm purposes. 

This integral relay is a latching alarm that can be reset with a magnetic tool without opening the enclosure.

C12-17 gas transmitters can be connected directly to PLC, DCS, or computer based alarm systems without additional hardware.

Combustible gas sensors are made up of two matched sensing elements, one active and one passive. 

Both are electrically heated and form two legs of a Wheatstone bridge circuit. 

When combustible gas contacts the sensor, the active element catalyzes the oxidation of gas heating the active element and changing it's resistance. 

The passive element remains unchanged, resulting in a change in the bridge circuit that is proportional to the gas concentration.

The C12-17 Combustible Gas Transmitter has explosion-proof sensor assemblies that are made of 316 stainless steel for maximum corrosion protection.
 
A sinter bonded flame arrestor provides the gas diffusion path to the sensing elements while maintaining the flame-proof integrity of the assembly. 

Sensing elements are specially designed for maximum poison resistance and long life in harsh industrial environments, with sensor life typically 2 years or more.
Features
  • Gas Type: Calibrated for methane unless otherwise ordered.
  • Display: 3-digit LCD optional
  • Range: 0-100% LEL
  • Response Time (T90): 10 seconds
  • Accuracy: on average ±5% of value
  • Electronic Repeatability: ±1%
  • Electronic Linearity: ±0.5%
  • Zero Drift: Less than 2% full scale per month
  • Span Drift: Less than 3% per month
  • Output: Powered 4-20 mA, 675 ohms maximum at 24 VDC
  • Power: 12-30 VDC, 100 mA maximum
  • Enclosure: Explosion-proof, Class 1, Div 1, Groups B, C, & D
  • Alarm: Optional single alarm available
  • Alarm Relay: SPDT, 5 Amp @ 220 VAC non-inductive, latching
  • Sensor: 316 stainless steel
  • Controls: Potentiometer zero and span adjustment, Potentiometer alarm setpoint adjustment, Magnetic reset switch for latching alarm relay
  • Operating Temperature: -40° to +70°C
  • Weight: 3 lbs (1.3 kg)

Specifications

Range

  • 0-100 % LEL (Lower Explosive Limit) Standard
  • 0-50 % LEL Optional

Response Time (T90)

  • 10 Seconds

Sensitivity

  • 1 % LEL

Zero Drift

  • < 2 %/Month

Power

  • 10-28 Vdc
  • 24 Vdc at 100 mA Nominal

Output

  • 4-20 mA DC
  • 200 ohms Max. load at 12 Vdc
  • 800 ohms Max. load at 24 Vdc
  • 1000 ohms Max. load at 28 Vdc

Display

  • Optional 2-1/2 digit LCD

Alarm

  • Single Setpoint or Trouble with SPDT, 1A, 125 Vac, 1A, 30 Vdc Alarm Relay

Temperature Limits

  • -40° to + 70° C

Sensor Materials

  • 316 Stainless Steel

Enclosure (Blind)

  • Galvanized Cast Iron for Blind Transmitter
  • Area Classification: NEC Class 1, Div. 1, Groups B, C, & D

Enclosure (For Display)

  • Extruded Aluminum with Glass Window
  • Area Classification: NEC Class 1, Div. 1, Groups A, B, C, & D

Connections

  • 3-Wire, 20 AWG, 500 Feet Max. (150 m)

Sensor Cable Length

  • Maximum 50 Feet for Separation Between Sensor and Transmitter

Weight

  • 3 lbs (1.4 kg)

  • Process Buildings
  • Analyzer Enclosures
  • Pump Stations
  • Gas Compressor Stations

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