Smart transmitter, GD-70D, C3H8 (propane), 0-100% LEL



GD-70D for C3H8 (propane), 0-100% LEL

The new Model GD-70D smart gas detection transmitter series sets a new standard for performance, flexibility, and versatility. The GD-70D sample-draw transmitter offers an array of sensor technologies unmatched in the industry, including unique offerings, such as our hydrogen-specific or LEL versions.

The long life high capacity pump and wide variety of sensing elements are replaceable in a few seconds, with no tools required! The smart sensors retain all calibration and sensor-specific data in non-volatile memory, so sensors can be hot-swapped in the field with no programming required. The sensors also retain calibration information, which means they can be conveniently calibrated separate from the transmitter, avoiding transport of calibration gases to the field location. The GD-70D firmware automatically corrects for long-term zero and span “drift” minimizing maintenance and maximizing reliability.

The GD-70D can be used as a stand-alone device, offering a number of communication protocols to existing PLC systems, or can be integrated with RKI’s Beacon series of single and multi-channel controllers.

All GD-70D transmitters include a large, easy to read integral LCD display, tri-color bar graph for visual notification of alarm status, programmable low and high alarm relays, and fault relay. Pump flow is self-tuning for maintenance-free operation. Because all GD-70D base units are identical, sensors can be interchanged with no programming or tools required, resulting in maximum flexibility to the user.
  • Monitor combustibles, O2, and a wide range of toxics
  • Monitor vaporized hydrogen peroxide (VHP) fumigation and disinfection
  • Plug and play smart sensors retain calibration and sensor data
  • Common platform (Main unit / Sensor / Pump) for all detection methods
  • Universal main unit (all sensor types)
  • Multifunctional sensor unit (New Intelligent sensor)
  • No internal tubing (main unit) / No coil (pump)
  • Front access, no tool required, easy sensor and pump replacement
  • Large size LCD screen
  • Various communication methods available (4-20mA, NT and PoE)
  • Minimal maintenance cost through enhanced troubleshooting firmware functions
  • Small mounting space
  • Environmentally friendly
  • Wide variety of sensors available
NCU Gas DetectedDetection RangeAlarm 1Alarm 2IncrementsPart #
H2 (Hydrogen)0 - 100% LEL10% LEL50% LEL1% LEL
H2 (Hydrogen)0 - 2.00% volume (NCU Type)1.00% vol1.00% vol0.01% volGD-70D-H2-20K
C4H10 (Isobutane)0 - 100% LEL 25% LEL25% LEL1% LELGD-70D-LEL-ISOB
CH4 (Methane)0 - 100% LEL25% LEL25% LEL1% LELGD-70D-LEL-CH4
CH4 (Methane)0 - 2% volume (NCU Type)1.00% vol1.00% vol0.01% volumeGD-70D-CH4-20K
Main Unit Specifications

Communication4-20mA DCDC power line communicationPoE method
Detection principleDifferent type depending upon sensor unit and detectable gas (see table)
Sampling methodSample draw (auto-adjustment of flow rate) 0.5 L / min +/-10%
Display• Large LCD display (white backlight)
• Gas concentration
• Flow rate, communication status, pyrolyzer status, gas detected
• Error code, content of error
Gas alarmsTwo alarm levels:1st alarm Red
2nd alarmRed
Fault alarmYellow
External output1st, 2nd, and trouble alarms:Relay contact output for each alarm
Self diagnostic functionSystem failure, sensor failure, flow failure, communication error NT / ET / Analog
DataloggingEvent history, alarm history, calibration history. Alarm trend (180 sec before / after 1st alarm)
Alarm Contact SpecificationsNo-voltage contact, 2 step independent, normally open (factory setting) or normally closed
Normally de-energized (energized during alarm, factory setting) or normally energized (de-energized during alarm)
Capacity:125 VAC 0.25A or 24 VDC 0.5A (resistive load)
Recommended Contact CableCable of CVV, etc. (1.25sq) - max. 6-core
Recommended Tubing4 mm x 6 mm Teflon
Max Tubing Lengths30 meters
Operation temp. & humidity0 ~ 40ºC, 30 ~ 70% RH (non-condensing)
Operating settingsAll operational settings are user adjustable through front panel
Power requirementsDC 24V+/- 10%, approx 1.5W (Max 4W including sensor unit)PoE standard arrangement
Note: Approx. 2.5W (Max 5W) with SGU sensor unit
DimensionsWidth2.8 in.70 mm
Height4.7 in.120 mm
Depth5.9 in.150 mm
WeightApprox. 0.9kg (2.0lbs), including sensor unit
MountingWall-mounting base plate by 2 or 3 screws
Sampling tubing4 x 6mm PTFE tubing recommended. Tube fittings provided as standard accessories
BushingCable type varies depending on communication method (Cable bushing optional)
Flow Rate0.5L/min ±10%
Outer ColorGas detector:Grey
Front door:White

Sensor Unit Specifications

Detection principleElectrochemical typePyrolysis-particle typeNew ceramic (Catalytic combustion)Semiconductor
Gas to be detectedRefer to list of
detectable gases
NF3/COS0-15ppm TEOS in air and othersCombustible gasCombustible gas
Toxic gas
Detection rangeSee Detection Gas chart
Detection methodPump suction typePump suction type/pyrolysis typePump suction type
Alarm setpoint valueSee Detection Gas chart
Alarm accuracyWithin ±30% to the alarm setpoint value±25% to the alarm setpoint valueCombustible: ±25% to the alarm setpoint value
Toxic: ±30% to the alarm setpoint value
Alarm delay time60 seconds or less by providing the gas 1.6 times the alarm setpoint (excluding delay in the tube and in the communication)30 seconds or less by providing the gas 1.6 times the alarm setpoint (excluding delay in the tube and in the communication)Combustible: 30 seconds or less by providing the gas 1.6 times the alarm setpoint (excluding delay in the tube and in the communication)
Toxic: 60 seconds or less by providing the gas 1.6 times the alarm setpoint (excluding delay in the tube and in the communication)
Alarm typeTwo-step alarm (H-HH)
Power consumption Approx. 1.5 W (Max. 4 W)Approx. 3W (Max. 5.5W)Approx. 2.5W (Max. 5W)
consumption (EA)
24 V: Approx. 3W (Max. approx. 5W)24 V: Approx. 4.5W (Max. approx. 6.5W)24 V: Approx. 4W (Max. approx. 6W)
PoE: Approx. 4.5W (Max. approx. 7W)PoE: Approx. 5.5W (Max. approx. 8.5W)PoE: Approx. 5.5W (Max. approx. 7W)
consumption (DV)
Approx. 2 W (Max. 4.5 W)Approx. 3.5W (Max. 6W)Approx. 3W (Max. 5.5W)
Operating temperature (at a constant condition)0 - 40ºC0 - 40ºC0 - 40ºC0 - 40ºC0 - 40ºC
Operating humidities (Non-condensing)30 - 70%RH30 - 80%RH95%RH or less
Self diagnosis functionSensor trouble, system failure
Date logging functionEvent history, alarm history, calibration history, Alarm trend (60 sec. before/after 1st alarm)

Pyrolyzer Unit Specifications

ApplicationNF3 / TEOS gases detected in air
UsageUsed by connecting to “GD-70D” (Main unit)
Power LampLED (Green color)
Warming-up:Flashing at every 1 sec interval
Trouble:Flashing at every 0.2 sec interval
Self-diagnostic functionPyrolyzer unit trouble
Fan trouble
System trouble
Operating temp. & humidity0-40° C, 30-70% RH (non-condensing)
Operational settingsAll operational settings are user adjustable through front panel
Power requirementsDC 24V+/- 10%, approx. 25W (max)
DimensionsWidth2.8 in. (70 mm)
Height4.7 in. (120 mm)
Depth5.9 in. (150 mm)
WeightApprox. 1.2kg (2.6lbs)
MountingWall-mounting base plate by 2 or 3 screws
Sampling4x6mm PTFE tubing recommended. Tube fittings provided as standard accessories
Bushing1.25sq 2 core cable for power supply DC24V (Cable bushing optional)
  • Placeholder

    Flow sensor for GD-70D

  • Placeholder

    Pump, RP-70 for GD-70D

  • Placeholder

    Pyrolyzer unit only for GD-70D

  • Placeholder

    Sensor, Isobutane (iC4H10) 0-100% LEL, sensor unit


Additional information

Weight 2 lbs
Dimensions 5.9 × 2.8 × 4.7 in