VG 300 Vacuum gauge The vacuum gauge VG 300 measures total pressures in medium and low vacuum field, up to 10-3 mbar. The measured pressure is indicated on the liquid crystal display (illuminated LCD - alpha-numeric and analogue) in three different measurement units, selectable by a small touch panel on the front side of the instrument. Two leds on the panel, red and green, display if the pressure set point has been reached. VG 300 is also a vacuum controller; it contains three relays, each with N.O. and N.C. contacts for remote applications, for example, the actuation of a vacuum valve or an alarm device. The two relays identified by HIGH and LOW are activated when the corresponding pressure set-points have been reached, either in the rising (HIGH) or in the descending (LOW) phase. Two L.E.D.'s, red and green on the front panel signal respectively the energised state of HIGH and LOW relays. The pressure value at the point where each of the two relays is energised, can be set separately and displayed on the indicator scale. The third relay identified by FAULT signals by means of a normally open contact, the malfunctioning of a system.