Economy Fixed Position Systems
Inexpensive fixed position gas detection systems for a variety of toxic gases and vapors.
GasSens is a flexible component system providing a variety of options to meet individual gas detection and alarm requirements. Economical and low maintenance, this system is your best choice for reliable leak detection. GasSens detection systems consist of individual modules that can be located where required. Sensor/transmitters located in the area where gas leakage or buildup might occur, provide the basic measurement for the system. Sensor transmitters are available in either NEMA 4X or explosion-proof versions and can be supplied with ATI’s exclusive Auto-Test automatic sensor testing system.
Receiver modules provide the electronic brains for the detection and alarm system. Each compact module includes a digital display of gas concentration, isolated analog output, and 4 relay outputs. Receivers may be located up to 1,000 feet from sensor/transmitters for remote indication or can provide local control functions such as valve shut off while transmitting a 4-20 mA signal to remote displays or dataloggers.
Receiver modules provide an interface between the detection system and external alarming and data logging requirements. One module is used with each sensor/transmitter.
- The LED display Indicates gas concentration directly in ppm, ppb or %. The display may be operated in high intensity mode for outdoor use or in normal mode for indoor application
- An isolated 4-20 mA output is standard. The output will drive loads up to 1,000 ohms for use in recording, data logging or computer input.
- Two alarm setpoints are factory adjusted to standard values but may be set to any value from 5% to 100% of range. Front panel LED’s marked Warning and Alarm indicate the status of each alarm setpoint. A standard alarm time delay of 2 seconds or a longer delay of 10 seconds may be selected. In addition, alarms may be switch programmed to activate either above or below the setpoint.
- Three alarm output relays are SPDT with unpowered contacts for use in activating external signaling devices, control elements or for input to telemetry or annunciator systems. Each relay may be assigned to either alarm setpoint for application flexibility. Relays are factory set to energize on alarm, but may be switch programmed for fail safe operation. Relays may be also set either latching or non-latching operation.
- Trouble alarm & relay should the sensor/transmitter input be lost, a trouble light (LED) on the front panel will flash and an associated relay will activate. For those systems equipped with the Sensor Auto-Test feature, this alarm will also activate if the sensor does not respond to the automated gas test.
- A single front panel switch marked A/R serves a number of functions. When an alarm occurs, the switch will silence an audible horn wired to the module and will change the alarm lights from flash to steady on. After the alarm condition has cleared, the switch will also activate an electronic module test, inhibit alarm contacts and activate the sensor Auto-Test.
- Terminals are provided for connection of a remote reset switch so that alarms can be acknowledged form a remote location or through a telemetry system.
- External electrical connections are made to plug in terminal blocks. Should module service ever be needed, modules can be replaced in minutes.
GasSens gas detection systems employ electrochemical sensors developed and manufactured by ATI. Expertise in electrochemistry and sensor design provide the foundation for leak detection systems that perform continuously with minimal maintenance. Sensors are rated for ambient temperature from -25 to 50ºC, allowing both indoor and outdoor applications. Excellent zero stability and high sensitivity and selectivity combine to make ATI sensors the best available.
Gas sensors are closely coupled to a digital transmitter for excellent noise immunity and the ability to transmit long distances using unshielded cable. The transmitter is powered from the receiver module and uses a unique current pulse position technique to send information to the receiver over a two wire connection. The receiver connection in not polarity sensitive, virtually eliminating the possibility of incorrect transmitter wiring. Sensor/transmitters can be located up to 1,000 feet from receiver modules.
Sensor/transmitters are housed in shielded NEMA 4X enclosures for use in almost any industrial environment and are designed to meet intrinsic safety standards. An explosion proof version is available.
Auto-Test – Savings & Safety
A major expense in gas detection systems is the cost of regular testing to ensure that sensors are responding. This requires a technician to inspect sensors weekly and apply a small amount of gas manually to check response. ATI has developed a unique system to reduce this maintenance requirement.
Available on most ATI digital sensor/transmitters is an option called “Auto-Test.” This option consists of an electrochemical gas generator closely coupled to the sensor. Every 24 hours, the receiver automatically activates the generator, producing a small amount of gas that diffuses into the sensor, just as it would if a gas leak occurred. The microcomputer is the receiver analyzes the output of the transmitter to determine that the sensor is responding normally. When proper sensor response is detected, the generator is turned off and the system goes back to normal operation. If no sensor response is detected, the TROUBLE light on the receiver will flash and the trouble relay will activate. During testing, alarm relays are inhibited so that external alarms are not activated.
The Auto-Test feature ensures that each sensor is regularly tested with gas. Premature sensor failure or blockage of the sensor membrane is quickly detected. In addition, self-testing will alert maintenance personnel when a sensor has reached the end of its useful life. Since sensors normally last anywhere from 12 months to over 3 years, this feature allows users to determine when sensor replacement is needed.
Power Supply Module
A compact universal power supply in a DIN rail module similar to the receiver was developed. The power supply will accept any AC or DC input from 85 to 225 volts, without adjustment.
Other options include a battery back up system and horn and strobe light options.
|Concentration Display||4 Digit LED, sunlight readable|
|Input||Digital signal, 2 wire connection to remote sensor/transmitter|
|Output||Isolated 4-20 mA or 0-20 mA DC, 1,000 ohms maximum load|
|Alarms||Two adjustable concentration alarms, setpoints adjustable form 5-100% of range|
|Alarm Indicators||High intensity LED bars for Warning (low setpoint) and Alarm (high setpoint)|
|Indicator Function||Warning indicator non-latching, alarm latching|
|Alarm Relays||Three assignable alarm relays, 10 A, 120 VAC (5A, 250 VAC) resistive alarm relays assignable to either alarm setpoint|
|Relay Function||Configurable for normal/fail-safe, latching/non-latching and fast/slow operation|
|Relay & Indicator Reset||Activated from front panel switch or through remote reset|
|Trouble Alarm||Front panel LED indicator and SPDT, 10 A 120 VAC (5A, 250 VAC) resistive relay; Relay factory set to fail-safe operation|
|Trouble Function||Indicates loss of sensor/transmitter input or failure of sensor Auto-Test (if in use)|
|Gas Indicator||LED bar on front panel with gas symbol overlay|
|Mounting||Module mounts to 35 x 7.5|