Abstract: In a modular signal mirroring system each point-to-point RF transceiver end has a controller module coupled to one or more I/O modules. The I/O modules have various input and output circuits. A signal received at the near end is reconstructed at the far end after being transmitted in an RF packet. The reconstructed signal may be the same as the input signal, inverted from the input signal or level-shifted from the input signal. It is representative of the input signal following the input signal's state after a time-quantization latency. Transmission between the two ends is via a periodic transmission controlled in a master slave protocol. If a transmission is not received in a timely manner or, in some systems, if intentional interference with transmissions is detected, the reconstructed signal is forced to a safe state determined by local switch settings. The settings include the last known good state.

Abstract: In a modular signal mirroring system each point-to-point RF transceiver end has a controller module coupled to one or more I/O modules. The I/O modules have various input and output circuits. A signal received at the near end is reconstructed at the far end after being transmitted in an RF packet. The reconstructed signal may be the same as the input signal, inverted from the input signal or level-shifted from the input signal. It is representative of the input signal following the input signal's state after a time-quantization latency. Transmission between the two ends is via a periodic transmission controlled in a master slave protocol. If a transmission is not received in a timely manner or, in some systems, if intentional interference with transmissions is detected, the reconstructed signal is forced to a safe state determined by local switch settings. The settings include the last known good state.

Abstract: A resistive liquid level/temperature sensor and transmitter including low voltage impedance measurement circuitry to convert three impedance values into indications of the temperature and the levels of two different liquids (e.g., oil and water) located within a storage tank. A resistive chain network including a plurality of series connected resistors and a corresponding plurality of reed switches extend longitudinally through a liquid level sensing probe that is dipped into the liquids in the tank. A pair of magnetic floats having different specific gravities surround the probe and rise to the two fluid levels. The magnetic floats close adjacent reed switches which create first and second current paths through the resistive chain network. The impedances of the first and second current paths are measured to provide an indication of the liquid levels. A resistive temperature device carried by the probe provides an indication of temperature.

Abstract: A cathodic protection monitor to be electrically connected to a cathodic protection rectifier that is adapted to prevent rust, corrosion and possible leakage in an underground pipe or storage tank above which the rectifier is supported. The cathodic protection monitor includes a CPU that reads, digitizes and stores analog current and voltage signals which are indicative of the effectiveness of the rectifier. The monitor includes an ISM band transceiver and antenna by which the CPU is polled and from which packets of stored data are transmitted to a data collector for retransmission and analysis by the pipe owner or maintenance crew. Synchronized timing signals are supplied (from the National Bureau of Standards) to a stable auxiliary clock by way of a WWVB transceiver and antenna so that a plurality of cathodic protection rectifiers can be turned on and off at the same time as may be required to compile ground voltage readings along the pipeline as part of a government-mandated survey.

Abstract: A cathodic protection monitor to be electrically connected to a cathodic protection rectifier that is adapted to prevent rust, corrosion and possible leakage in an underground pipe or storage tank above which the rectifier is supported. The cathodic protection monitor includes a CPU that reads, digitizes and stores analog current and voltage signals which are supplied from the DC output of the rectifier and are indicative of the effectiveness thereof. The monitor includes an ISM band transceiver and antenna by which the CPU is polled and from which packets of stored data are transmitted to a data collector at an overhead airplane or nearby motor vehicle for retransmission and analysis by the pipe owner or maintenance crew.

Abstract: The cathodic protection monitor includes a CPU that reads, digitizes and stores analog current and voltage signals which are supplied from the DC output of the rectifier and are indicative of the effectiveness thereof. The monitor includes an ISM band transceiver and antenna by which the CPU is polled and from which packets of stored data are transmitted to a data collector at an overhead airplane or nearby motor vehicle for retransmission and analysis by the pipe owner or maintenance crew. Synchronized timing signals are supplied (from the National Bureau of Standards) to a stable auxiliary clock by way of a WWVB transceiver and antenna so that a plurality of cathodic protection rectifiers can be turned on and off at the same time as may be required to compile ground voltage readings along the pipeline as part of a government-mandated survey.

Abstract: An ultrasonic monitor to measure the level of a fluid (e.g., oil or water) within a storage tank. The ultrasonic monitor is surrounded by a gas-tight, explosion-proof casing that is coupled to the top of the tank so that the acoustic axis of a (e.g., 59 KHz) ultrasonic transducer is directed downwardly towards the surface of the fluid. The ultrasonic transducer is encased within a protective (e.g., Delrin) housing so as to resist the hostile (e.g., acidic, gaseous vapors and extreme temperature) conditions within the tank. A main CPU is interconnected between the ultrasonic transducer and an RF transceiver having an antenna from which fluid level data calculated by the main CPU can be transmitted over a wireless communication path. A reference rod having at least one acoustic reflector located at a known distance therealong extends downwardly from the housing of the ultrasonic transducer towards the surface of the fluid.

Abstract: A system for monitoring a gas/oil well is provided with a monitoring unit, a relay unit and a host interface. A monitoring unit collects data regarding the status of the gas/oil well and wirelessly transmits that data to a relay unit. The relay unit, in turn, connects to a host interface using cellular communications and transmits the data. The monitoring unit can transmit information on demand or after an alarm condition is sensed. In either case, the monitoring unit is normally in a sleep mode. The relay unit can request information from the monitoring unit or respond to a wake up transmission sent to it from either the host interface or monitoring unit. The host interface receives data from the relay unit and then informs an end user of that data.