Manual

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Table of Contents
1 Introduction .............................................................................. 1
1.1 Model 286 Features................................................................... 1
1.2 Front Panel Layout................................................................... 3
1.3 Rear Panel Layout..................................................................... 4
1.4 Model 286 Specifications @ 25 °C .......................................... 6
1.5 Controller Modes Description................................................... 7
1.5.1 Normal Mode ................................................................. 7
1.5.2 Auto-Changeover Mode................................................. 8
1.5.3 Pre-Cool Mode................................................................ 9
2 Installation .............................................................................. 11
2.1 Unpacking the Instrument..................................................... 11
2.2 Rack Mounting the Instrument ............................................. 12
2.3 Installing the Sensors in the Vessels..................................... 12
2.4 Connecting the Oscillator Cables to the AMI Sensors.......... 13
2.5 Connecting C and D Sensor Inputs to the Oscillator............13
2.6 Installing the Optional Solenoid-operated Fill Valves..........14
2.7 Connecting to Optional Analog Outputs................................ 15
2.8 Connecting to Communication Options ................................. 15
2.9 Connecting the Instrument to Power..................................... 15
3 Calibration .............................................................................. 17
3.1 Calibration Concepts............................................................... 17
3.2 Calibration Methods................................................................ 19
3.2.1 Open Dewar Calibration ............................................. 21
3.2.2 Closed Dewar Calibration........................................... 22
3.2.3 Approximate Calibration ............................................ 26
3.3 Calibration Menu Reference................................................... 29
3.3.1 CAL Menu and Passcode Entry.................................. 30
3.3.2 Sensor Input Selection ................................................ 30
3.3.3 Action for Selected Input............................................. 30
3.3.4 Select Calibration Sub-Menu...................................... 31
3.3.5 Perform Calibration Sub-Menu .................................. 33
4 Operation................................................................................ 37
4.1 Operational Guidelines........................................................... 37
4.1.1 Energize the Instrument............................................. 37
4.1.2 Assign Sensor Inputs to the Channels....................... 38