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S330.smartFill V02

Two pressurised tanks are used to supply liquid nitrogen to a group of cryogenic freezers. The tanks operate in 'mutual exclusion', i.e. in alternating mode. Each tank is equipped with a level transducer operating in 4/20 mA. When the system is switched on for the first time, the first tank is activated by opening solenoid valve #1. When its level falls below 10% (programmable threshold), solenoid valve #1 closes and the second tank comes into operation by opening solenoid valve #2. From this point on, the level of the second tank will be monitored and when it drops below 10% (programmable threshold), solenoid valve #2 will close and solenoid valve #1 will open again. This cycle will be repeated indefinitely. Whenever a tank falls below 10% (programmable threshold), a warning signal is generated via a relay inside the S330.smartFill device to alert the gas supplier that it is time to replace the empty tank with a full one. At any time, the user can press the appropriate button on the touchscreen display to switch from tank #1 to tank #2 and vice versa.