Instruction Manual VGC301A Controller
InstruTech, Inc.
Page 3
1
Introduction / General Information
1.1
Description
The VGC301 vacuum gauge controller is a convenient and inexpensive power supply and readout instrument for
the InstruTech CVG101
Worker Bee™
convection-enhanced
Pirani vacuum gauge or a Granville-Phillips
®
275
Convectron
®
gauge. The 1/8-DIN housing can be used as a bench top, or mounted in a cutout in an instrument
panel. The VGC301 is powered by 12-30 VDC, or by its self-contained universal 100-240VAC supply.
Thermal conductivity gauges measure pressure indirectly by sensing the loss of heat from a sensor to the
surrounding gases. The higher the pressure of the surrounding gas, the more heat is conducted away from the
sensor. Pirani thermal conductivity gauges maintain a sensor (usually a wire) at some constant temperature,
and measure the current or power required to maintain that temperature. A standard Pirani gauge has a useful
measuring range of about 10
-4
Torr to 10 Torr. By taking advantage of convection currents that are generated
above 1 Torr,
convection-enhanced
Pirani gauges increase the measuring range to just above atmosphere.
The VGC301 signals and relay functions are the same as found on similar convection gauge controllers from
other manufacturers. The VGC301 Controller, CVG101 vacuum gauge tube and gauge cable can be directly
interchanged with Brooks Automation, Inc. / Granville-Phillips
®
375 controller, 275 Convectron
®
gauge and gauge
cable. (Remote interface, relay and power connectors are different.)
1.2 Specifications
measurement range (signal)
1.0 x 10
-4
to 1000 Torr / 1.3 x 10
-4
to 1333 mbar / 1.3 x 10
-2
Pa to 133 kPa
display
LCD, 4 digits, user-selectable Torr, mbar, or Pa,
(4 digits from 1100 Torr to 1000 Torr), (3 digits from 999 Torr to 10.0 mTorr),
(2 digits from 9.9 mTorr to 1.0 mTorr ), (1 digit from 0.9 mTorr to 0.1 mTorr)
display engineering units
Torr, mbar, or Pa - user selectable
display update rate
0.5 sec
weight
9 oz (250 g)
operating temperature
0 to +40
o
C
storage temperature
-40 to +70
o
C
humidity
0 to 95% Relative Humidity, non-condensing
altitude operating
6,560 ft (2,000 m) max
storage
41,000 ft (12,500 m) max
analog output (user-selectable)
a) non-linear S-curve 0.375 to 5.659 Vdc, or
b) linear 0 to 10 Vdc - user scalable, or
c) log-linear 1 to 8 Vdc, 1V/decade
serial communications
RS232 and 2 wire/4 wire RS485 - ASCII protocol
housing
1/8-DIN panel-mount enclosure
input power
100-240 Vac, 50/60Hz, universal power supply or 12-30 Vdc, 2 W
setpoint relays
two single-pole double-throw relays (SPDT), 1A at 30 Vdc resistive, or ac non-inductive
connectors
gauge: 9-pin D-sub female
analog output and digital interface: 9-pin D-sub male
relay outputs: 6-pin pluggable terminal block
power: universal AC and 2-pin pluggable terminal block DC
RF/EMI protection
CE compliant