Vacuum Sensors or Vacuum Gauge can send a signal to a readout or a vacuum controller.
Sensors do go bad overtime and are typically easy to replace.
Gauge cables are not always included when purchasing a vacuum gauge / sensor.
Duniway Stockroom Corp I 100 K Vacuum Ionization Tube
Edwards Penning Vacuum Gauge Head Model CP25-K
Granville 275 Pirani Sensor for Vacuum
Granville 275071 Cables with Sensor for Vacuum Readout
Varian Eyesys ConvecTorr Vacuum Gauge
Varian Ionization Gauge Model 563 Glass Sensor