The Varian L8350-301 Multi-Gauge Controller is a half-rack modular vacuum measurement and control instrument supporting simultaneous operation of up to three ion gauges, eight thermocouple gauges, and multiple specialty gauge types. Its flexible architecture accepts up to five optional printed circuit boards (PCBs), enabling field reconfiguration without factory intervention. The unit accommodates Bayard/Alpert, UHV, inverted magnetron, cold cathode, and capacitance diaphragm gauges—including up to four ConvecTorr™ gauges and two capacitance diaphragm boards with two heads each. A backlit custom-color LCD with ±45° viewing angle displays pressure readings via a 15-segment bar graph spanning 10⁻³ Torr to atmosphere, three-digit mantissa with optional fourth digit, and ±1½ digit exponent. All front-panel controls provide access to measurement, setpoint, and remote I/O functions. The controller operates from 90–127 VAC or 208–250 VAC (50/60 Hz) and retains parameter values for up to four years of accumulated off-time during power loss.
Technical Specifications
• Gauge Capacity: Three ion gauges, eight thermocouple gauges, four ConvecTorr™ gauges, or two capacitance diaphragm boards (two heads per board)
• Capacitance Diaphragm Gauge Accuracy: 0.1% to 1%, full-scale range 0.1–1000 Torr
• CDG Heated Sensor Range: 35–75°C (reduces condensation, extends warm-up time)
• Modular Slots: Up to five optional PCB positions
• PCB Restrictions: Maximum three high-profile boards (Bayard/Alpert, UHV, cold cathode, capacitance diaphragm); two thermocouple boards; one setpoint board; one manual I/O board; two capacitance diaphragm boards maximum
• Power Input: 90–127 VAC or 208–250 VAC, 50/60 Hz, switchable
• Operating Temperature: 0°C to 50°C
• Calibration Temperature: 25°C ±5°C, 90% relative humidity (non-condensing)
• Data Retention: Four years accumulated off-time
• Display: Backlit custom-color LCD, ±45° viewing angle (downward bias), 15-segment pressure bar graph with annunciators for units, emission, degas, and setpoint status
– Key Features
• Modular PCB insertion/removal enables in-field gauge type and function reconfiguration
• Front-panel keyboard controls all functions except rear power switch
• Readable in dark rooms and typical laboratory lighting conditions
– Typical Applications
• Multi-point vacuum system monitoring across pressure ranges from 10⁻³ Torr to atmosphere
• Process control with setpoint and remote I/O integration
– Compatibility & Integration
• ConvecTorr™, ion, thermocouple, Bayard/Alpert, UHV, inverted magnetron, cold cathode, and capacitance diaphragm gauge support
• Optional setpoint and remote I/O boards for process automation
