Intrinsically safe multi-drop communications link
AssigneeTechnical Oil Tools Corporation
InventorTommy L. Jobe
Life of this patent
Estimating the term…
Abstract
A multi-drop communication link, consisting of a master and a plurality of slaves is intrinsically safe for use in a hazardous environment. Slaves are in parallel and communicate with the master through transmit and receive shunt-diode safety barriers. An opto-coupler interface is provided between each slave and the transmit and receive circuits communicating with the master. The opto-couplers comprise infrared emitter-detector pairs which can be spaced apart by an intrinsically safe distance.
Claims12
An intrinsically safe multi-drop communications link between a master and a plurality of slaves, comprising:
- a transmit line extending from the master and toward each slave;
- a receive line extending from the master and toward each slave;
- voltage-limiting means and current-limiting means between the master and the transmit and receive lines;
- and
- opto-coupler interfaces respectively between each slave and the transmit and receive lines, each opto-coupler interface comprising an emmitter-detector pair spaced apart by an intrinsically safe distance, whereby intrinsically unsafe conditions cannot occur.
An intrinsically safe multi-drop communications link comprising a master having an output and an input means and a plurality of slaves, the slaves being in parallel;
- a transmit line extending from the master output means toward each slave;
- a receive line extending from each slave toward the master input means;
- a first shunt-diode safety barrier circuit in the master output means and a second shunt-diode safety barrier circuit in the master input means;
- and an opto-coupler interface at each slave communicating between each slave and the transmit and receive lines extending thereto, the opto-coupler interface comprising emitter-detector pairs spaced apart by an intrinsically safe distance whereby intrinsically unsafe fault conditions cannot occur.
An intrinsically safe multi-drop communications link for use in the presence of potentially flammable hydrocarbon vapors produced from a subterranean oil or gas well bore;
- comprising:
- a master computer located in the potential presence of the hydrocarbon vapors;
- a plurality of slave devices each located in the potential presence of the hydrocarbon vapors;
- a master output and a master input;
- a first shunt-diode safety barrier circuit at the master output and a second shunt-diode safety barrier circuit at the master input;
- a transmit line and a receive line extending from the master computer toward each slave device and communicable respectively with the master computer through the first and second shunt-diode safety barrier circuits;
- and
- an opto-coupler interface at each slave device communicating between each slave device and the transmit and receive lines extendig thereto, each opto-coupler interface comprising emitter-detector pairs spaced apart by an intrinsically safe distance whereby intrinsically unsafe fault conditions cannot occur in the multi-drop communications link.
Dependencies are inferred from the claim text.