Abstract: A system and method is disclosed for synchronizing clocks in a plurality of devices connected by a communication channel. A master control device is coupled to one or more slave control devices, e.g., event recorders, across a communication channel. Preferably, the communication channel is implemented according to an RS-485 interface. By periodically interrogating and monitoring the responses of each of the slave control devices, the master control device determines the transit time, i.e., communication, delays to each of the slave control devices. Operating in conjunction with this data, the master control device can then interpret and/or adjust any event times reported by the event recorders to improve the relative time accuracy of the event recorders as compared to a time maintained by the master control device. Consequently, the control system can achieve a relative time synchronization accuracy between the master and slave times to within 100 microseconds and preferably 100 nanoseconds or less.

Abstract: A multipoint communications system for transmitting the values of a multiplicity of analog parameters from one point digitally to another point and reconverting then into analog parameters. The system includes a plurality of input modules which communicate with respective output modules over a communications link. The input and output modules are configured similarly with a control processor connected to either multiplexing circuitry, in the case of an input module, or demultiplexing circuitry in the case of an output module. The multiplexing circuitry is connected to a plurality of configurable input circuits which receive the values of the various measured conditions or parameters. The demultiplexing circuitry is connected to a plurality of configurable output circuits which output the values of the various measured conditions or parameters. In a preferred protocol, a link master is chosen from among the input modules to generate a polling sequence for the input-output module pairs.

Abstract: A plurality of spaced parallel guides are mounted on a support. The edges of printed circuit boards are mounted in these guides. The printed circuit boards are formed with the male portion of an electrical connector at one end and a locking and regulating plunger at the opposite end.The support is provided with the female portion of an electrical connector which is positioned so that when the edges of the printed circuit board are mounted in the guides, the male part of the connector is aligned with the female connector whereby the male connector can penetrate the female connector. The plunger both locks the printed circuit board on the rack and regulates the depth of penetration of the male connector into the female connector.

Abstract: This invention relates to a pressure transducer and more particularly to a pressure transducer having means by which the pressure transducer can be removed from a pressurized line without loss of line pressure. The pressure transducer is mounted in a housing, which is adapted to be releasably mounted on a bracket. The bracket is provided with a tubular needle valve coupling which is adapted to be connected to a pressurized line. The coupling normally keeps the pressurized line closed, but when the housing of the pressure transducer is mounted on the bracket, the needle valve in the coupling is automatically actuated, opening the pressure transducer to the pressure in the line.