GDS 305 – Sequential Gas Sampling System 1-48 Way

  • 1-48 sample points
  • Monitor up to 4 gas types
  • No sample line purge delay
  • Wide range of sensor types
  • 4 line alpha/numeric display
  • Selectable sample line sequence
  • Display of each sample line location
  • Easily installed and maintained
  • Full indication of all operations
  • Event logging / Modbus / RS232 / RS485
  • Line blockage and pump fail monitoring
  • Variable sample time for optimum cycle time
  • High integrity, comprehensive self check fault monitoring
  • Centralised one man calibration offers minimum running costs
  • Split system operation – optional
  • Line blockage, blow back – optional
  • Hazardous area operation – optional
  • Remote repeater panel – optional
  • LED/text indicator panel – optional
  • Auto flood cut off – optional
  • Enclosure internal gas monitoring with automatic system shutdown – optional
  • Sample line multiplier – optionalshutdown – optional



The GDS 305 system is designed to monitor gas levels from a number of sample-points, targeted at situations where the positioning of conventional gas sensors may not be practical.
This may be due to equipment security, cable routing, access for detector head installation/maintenance, harsh environment or a cost effective means of monitoring designated hazardous areas, typically – tunnels, marine applications, underground/high level voids, process control, landfill, multi storey car parks, brewing, horticulture, retail.


Gas samples are sequentially extracted for a timed period by a central control unit via fixed sample lines. A high rate sample is taken by the main pump during which a reduced rate sample is passed across the sensor device.
The central unit provides gas level readouts with two alarm trip points per line, providing a range of signal outputs for annunciator and control functions.

Technical Data

Sensor Points
  •  1-48
  •  1-4 4~20mA input
  •  Combustible gas L.E.L. % Vol
  •  Toxic gas P.P.M. % Vol
  •  Oxygen – % Vol
  •  Refrigerant – ppm
  •  Depletion/enrichment
Power Supply
  •  230/115v AC 50/60 Hz
  • 300W max
LED Indicators
  •  System healthy
  •  Main power
  •  Standby power
  •  High gas alarm
  •  Low gas alarm
  •  System, flow, sensor fail
  •  Comms fail
  •  Skip/hold
  •  Sampling
  •  4 line alpha/numeric indicates all functions and status in text. Sample line locations (user settable)
User interface
  •  8 panel mounted push buttons:- Reset, Scroll, Hold, Dim, Enter, Down, Up, Select
  •  PC – event log / data log, data to and from system controls
Relay Outputs
  •  Global Low S.P.C.O.
  •  Global High S.P.C.O.
  •  Global Fault S.P.C.O.
  •  Flow Fail S.P.C.O.
  •  Power Fail S.P.C.O.
  •  Cabinet Sensor S.P.C.O.
  •  32 programmable relays

Additional 32 optional

  •  RS232– Data Stream
  •  Modbus 2 x RS485
  •  Can bus – internal
  •  Audible alarm all alarm conditions
  •  LED/display dimming
  •  User/Eng password
  •  LCD backlight
  •  Event logging
  •  Sample line size 8mm OD 6mmID
  •  Nylon, PTFE, Copper, Stainless Steel. Max length 200m specials 300m+
  •  Sample vent x 2-10mm
  •  Tubing entry enclosure base, side option
  •  Response time 15 to 45 seconds
  •  Colour- powder coat ash grey BSA01
  •  Size 800H x 600W x 350D
  •  IP 63
  •  Wall mount
  •  Weight 65kg
  •  EN60945: 2002

Maritime general requirements

  •  EN61010: 2001
  • Electrical Safety – LVD


GDS 305 sequential gas sampling system

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