GT-430 Thermistor Digital Display

GT430 Thermistor

GT-430 Product Manual – click to download (Note: Requires the Adobe Acrobat Reader.)

The 430 THERMISTOR GAUGE reads from atmosphere to 1 X 10-3 Torr plus Trend SensingTM, a unique feature that allows the user to see which direction the pressure is going.


  • Measures from atmosphere to 1 X 10-3 torr
  • NO mounting restrictions of sensor (as with Convectron Gauges)
  • Trend SensingTM shows direction of pressure change
  • Easy to read pressure display
  • Two adjustable independent relay outputs
  • LED indication of Pressure range, set point indication/set value and status
  • RS-232 serial interface
  • Analogue output (0-3 volts) for remote display/monitoring
  • Leak detection function over vacuum range
  • Front panel LED’s for relay output status
  • Panel mountable (1/8 DIN) or bench top use
  • Uses GT-034 sensor


The GT-430 thermistor vacuum gauge is a digital single station gauge for use in harsh environments. It incorporates Trend SensingTM technology that indicates which direction pressure is going. Trend SensingTM enhances vacuum leak detection capabilities. The controller is housed in a 1/8 DIN-style case. The unit uses the rugged and proven GT-034 thermistor sensor and covers a pressure range of 1 X 10-3 Torr to atmosphere. Pressure is displayed 4 digit monitor with torr and millitorr indicators. A nine segmented bar graph displays pressure direction. This segmented display provides high sensitivity that it can be used for vacuum leak detection with a solvent.

The relay set point for each station may be viewed by pressing the “View” buttons on the front panel. The gauge features two independent relays that can be set within the range of the gauge, each set point includes a separate high and low pressure value. Three front panel buttons allow the user to toggle through and adjust the values. LED’s indicate which value is being displayed with separate LED’s to indicate the status of the set points. The unit features an RS-232 serial interface that allows a remote system to request information and a separate linear analog voltage output that is proportional to pressure.

GT 430 Thermistor Gauge

Principle of Operation

A single resistor element is employed in a bridge-type detector driven from a constant regulated power source. The inverse resistive characteristics of the sensor unbalances the bridge as pressure changes occur, thereby causing a current change. A microprocessor scales the changes into pressure units. Trend SensingTM electronics enhances the sensitivity of each range by displaying the rate of change of the pressure on a separate bar graph.

Leak Detection

Trend SensingTM technology puts the gauge in constant Leak Detect Mode. Front panel Bar graph high sensitivity indicates to vacuum pressure changes. The bar graph will give quick feedback when the pressure makes a rapid change.


Power Input: 100-120 VAC 50/60 Hz 15 watts or 9-12 VDC
Pressures Scales: 760 Torr to 1 X 10-3 Torr
Number of Sensing Stations: One
Pressure Sensing Tube: Type GT-034 with 1/8” pipe thread or 0.406” diameter O-Ring sealing surface.
Tube Cable: 10 ft length standard with both 9-pin gauge and octal sensor connector
Cabinet Dimensions: 3.78” wide 5.1” deep 1.89” high
Mounting Hole Dimensions: 3.64″ wide x 1.75” high (allow 8” for mounting depth)
Relay Connections:One removable six position terminal block with common, normally closed, normally open connections for each set point.
Relay Trip Points Adjustments: Entire range of gauge
Relay Types: SPDT 5 Amp 250 VAC Max
RS-232: RX, TX, and COM (9600 Baud)
Analog Output: 0-3 Volt, (COM and OUT)
0-100mTorr:  +/-10% or 1mTorr, whichever is greater
100-500mTorr:  +/-15%
500-1000mTorr:  +/-20%
above 1000mTorr:  +/-40%

Ordering Information

THERMISTOR GAUGE – DIN panel mount with digital display dual set points scale indication from atmosphere to 0 torr with cable, less sensor – Part Number 500681-0010

GT-430 Thermistor  Digital Display with Trend Sensing Technology – As above, complete with GT034 sensor –  Part Number 500681-0011

GT-034 Thermistor gauge sensor – Part Number 277289

Vacuum Port Adapters

  • KF-16 to 1/8″ FPT KF – Part Number 500230-16
  • KF-25 to 1/8″ FPT – Part Number 500230-25
  • KF-40 to 1/8″ FPT – Part Number 500230-40
  • KF-50 to 1/8″ FPT – Part Number 500230-50
  • CF-16 to 1/8″ FPT – Part Number 500231-1
  • CF-35 to 1/8″ FPT – Part Number 500231-2
  • 1″ hole mount to 1/8″ FPT – Part Number 500236

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