The HPS® hot cathode sensor is Bayard-Alpert style, which utilizes a fine wire collector located at the center of a grid. Due to its small area, few x-rays hit the collector; therefore, the gauge can measure very low pressures. The 909AR transducer includes two yttria-coated iridium filaments for reduced downtime. Yttria-coated iridium is resistant to damage caused by high oxygen partial pressures and exposure to atmosphere. The tube sensor operates at lower temperatures, giving a lower chemical reaction rate and minimizing thermal interference. The sensor includes a screen to shield it from large particles.
The Series 909AR includes RS232 / RS485 digital communication as a standard feature. Digital communication allows for all adjustments and monitoring to be delivered real-time, via a host computer. For additional process control, the 909AR has a relay set point. The set point pressure, hysteresis and direction can all be adjusted and monitored via the digital port. The Series 909AR also features analog controls and analog output with 0 to 10 volts semilogarithmic output, 1 volt per decade for simplified system integration.
