Abstract: A material property sensor for a pressure transmitter comprises a sensing pattern immersed in a fill fluid. The pressure transmitter comprises a diaphragm configured for contact with a process fluid at an exterior surface of the diaphragm. The pressure transmitter further comprises a pressure sensor configured for sensing a pressure of the process fluid on the diaphragm. The pressure sensor and the diaphragm define a cavity within which the fill fluid is disposed such that the diaphragm of the pressure sensor is in contact with the fill fluid at an interior surface of the diaphragm. The sensing pattern is immersed in the fill fluid within the cavity and configured to measure an electrical property of the fill fluid at an initial time and at one or more subsequent times during operation of the pressure transmitter.

Abstract: A material property sensor for a pressure transmitter comprises a sensing pattern immersed in a fill fluid. The pressure transmitter comprises a diaphragm configured for contact with a process fluid at an exterior surface of the diaphragm. The pressure transmitter further comprises a pressure sensor configured for sensing a pressure of the process fluid on the diaphragm. The pressure sensor and the diaphragm define a cavity within which the fill fluid is disposed such that the diaphragm of the pressure sensor is in contact with the fill fluid at an interior surface of the diaphragm. The sensing pattern is immersed in the fill fluid within the cavity and configured to measure an electrical property of the fill fluid at an initial time and at one or more subsequent times during operation of the pressure transmitter.

Abstract: Disk drive spin-up is staggered to reduce peak power requirements. Spin-up of the drives is controlled by selectively delaying voltage inputs to the disk drives. Alternately, spin-up of the drives is controlled by staggering the timing of communications to the disk drives.

Abstract: Disk drive spin-up is staggered to reduce peak power requirements. Spin-up of the drives is controlled by selectively delaying voltage inputs to the disk drives. Alternately, spin-up of the drives is controlled by staggering the timing of communications to the disk drives.

Abstract: In a highly available environmental monitoring system, several slave devices are associated with either a fast polling list or a slow polling list. The fast polling list is polled by a master device more frequently than the slow polling list. A slave device is associated with the fast polling list if the slave device responds to a poll from the master device within a time period, and is associated with the slow polling list if the slave device does not respond to the poll from the master device within the time period. Furthermore, several control devices arbitrate to determine which shall be the master device for controlling several serial buses. The master device periodically switches between the plurality of serial buses to communicate with slave devices.

Abstract: A monitoring system in an alarm apparatus includes a central panel for controlling operation of the alarm apparatus, first and second terminals, the second terminal including a communication device, such as a microcontroller, to communicate with the central panel. A communication link comprising fiber-optic cables is further provided to connect the first and second terminals. The first terminal includes a signaling device to signal to the communication device when there is a break in the communication link. Responsive to the signal, the communication device signals to the central panel that there is a break in the communication link. In accordance with other aspects of the present invention, a plurality of intelligent peripherals, such as detectors and audible and visual alarms, are connected and controlled by the central panel via the fiber-optic cables.