The AVC-485 Automatic Valve Controller is designed to permit either manual or fully automatic operation of diffusion, turbo, or cryopumped high vacuum pumping systems. Provision is made, or can easily be added by the customer, for a variety of interlocks to protect the vacuum system from improper sequencing of values or the presence of unusual but damaging conditions. 
 
The AVC-485 is powered from a 115 volt, 2 amp source and will handle the three basic electropneumatic vacuum valves (roughing, foreline, high vacuum) and a solenoid vent valve in any vacuum system. A screw-driver switch determines the operation mode with separate panel light indicators. 
 
Time delay, for sequential automatic valve operations is preset. Settings can be changed to match a customer’s requirements. 
 
A clear and bold schematic of a typical system is on the front panel to assist in tracing the function being performed. In the automatic mode, LEDs on the schematic indicate valve status. 
 
The panel meter indicates the station pressure in the chamber and at the foreline or regen line. The sensors are the highly reliable and stable GT-034 thermistor tubes. 
 
Operator-Selectable Phases – Pressing the system stop button closes all vacuum valves except the foreline valve on Diffusion/Turbo pump systems, putting the system in a standby condition. Pressing the system vent button puts the chamber in the standby condition and then opens the chamber vent valve. The vent valve is closed automatically after a preset time to conserve backfill gas.