Communications: electrical – Selective – Intelligence comparison for controlling
Reexamination Certificate
1999-07-07
2003-02-25
Horabik, Michael (Department: 2635)
Communications: electrical
Selective
Intelligence comparison for controlling
C714S819000, C714S037000
Reexamination Certificate
active
06525647
ABSTRACT:
FIELD OF THE INVENTION
The invention generally relates to a Door Controller Unit (DCU) of the type typically used to control the operation of a door operator for a doorway of a passenger transit vehicle. More particularly, the invention relates to a system and method for verifying the authenticity of the door control signals that the DCU receives from a Central Door Controller (CDC).
BACKGROUND OF THE INVENTION
The background information below is provided to assist the reader to understand the environment in which the invention will typically be used. The terms used herein are therefore not intended to be limited to any particular narrow interpretation unless explicitly stated otherwise in this document.
Shown in
FIG. 1
is a typical passenger transit train. It has a lead railcar
16
and a plurality of trailing railcars
16
each linked serially by means of a mechanical coupler. Various electrical trainlines span the length of the train. Each trainline is composed of a series of interconnected wires or wire pairs, with each such wire/pair bundled (along with the wires/pairs of the other trainlines) within a protective conduit contained within each railcar. Each such conduit connects via a connector to another such conduit on a neighboring railcar so as to extend each trainline along the train. These trainlines are used to carry the electrical signals that are needed to operate and control the various systems on each railcar in the train.
Each railcar in the train typically has its own power distribution network (LVDN) from which it provides the relatively low voltage needed to power all of the electrical/electronic systems on the vehicle. The power level provided to the LVDN typically ranges from 12 to 150V dc (52V dc nominal), depending on the particular type of railcar at issue and the power requirements imposed by the transit authority.
Like the lead railcar, each of the trailing railcars may be equipped with one or more motors and a propulsion controller unit with which to control them. These propulsion controllers are connected by one or more trainlines to a master controller unit (MCU) located in the lead railcar. Using the controls of the MCU, a train operator can control, in addition to the mechanical brakes on each railcar, the operation of all of the propulsion controllers in the train. It is thus from the MCU that the train operator can operate the motors on all railcars in unison to propel or brake the train.
Transit railcars each have one or more doorways
12
through which passengers can enter and exit the vehicle. For railcars with more than one doorway, the openings
12
may be located in the same sidewall or opposite sidewalls of the vehicle. Near each doorway
12
is installed a Door Hardware System (DHS), also referred to as a door operator
15
, to which the door panel(s) attach. The door operator is what actually moves the door panel(s) back and forth over the doorway to open and close the doors, depending on whether its pneumatic or electric motor is commanded to operate in the opening or closing direction. Plug doors, pocket doors, outside sliding doors and station platform doors are just some examples of the types of door systems currently being used in the transit industry.
The doors of the railcars in a passenger train are also centrally controlled from the lead railcar. Specifically, a central door controller (CDC)
1
housed in the lead railcar communicates with, and controls, one or more door controller units (DCU)
74
on each railcar through a number of discrete door control trainlines. The central command (i.e., door control) signals that the CDC
1
conveys along these trainlines each typically takes the form of a DC signal, the exact level depending on the requirements imposed by the transit authority. Each DCU
74
controls one or more door operators
15
, and their associated motors, based on the input signals that it receives from two sources: (1) the central command (i.e., door control) signals received from the CDC
1
via such trainlines and (2) the various local door hardware signals received from the door operator(s)
15
and related hardware.
Transit authorities typically use a separate trainline to convey, to the DCUs on every railcar in the train, each of the central command signals. The following central command signals are typical: door unlock, door open, door close, door lock, side select enable, cliff side select enable, zero speed, park brake applied, and low speed. As noted earlier, there are many different types door systems in use in the passenger transit industry. Consequently, not every transit authority uses every one of the aforementioned central command signals. In some systems, for example, the door unlock and lock signals may be subsumed by the door open and close signals, respectively.
Each door control trainline typically takes the form of a single-switched input format or a doubled-switched input format. The particular format depends on the preference and tradition of the transit authority at issue. In the single-switched format, only the main input line is activated when a central command signal is sent, its associated return line (commonly the ground) being hardwired to the CDC. In the doubled-switched format, both the input line and its associated return are activated together at the CDC. When a double-switched input is not in use, both of its lanes are shorted together at the CDC to reduce the chance that unwanted bias voltages (or ground loops) will inadvertently be interpreted by a DCU as a valid incoming central command signal.
The electrical characteristics of the central command signals are also prescribed by the transit authorities. Some transit authorities implement their central command signals as a −50V DC signal, referenced to ground. The voltage, current, polarity and other attributes of the central command signals, however, vary among transit authorities. For this reason, the input circuitry of a DCU must be designed to comport with the input requirements imposed by the transit authority.
The electromagnetic environment in which a transit train operates has profound affect on the electronic circuitry of a DCU. As an electrically powered conveyance, a transit train typically acquires the energy it needs to power its operations from an overhead catenary, a third rail or similar power carrying conduit. An energy collector, mounted to at least one railcar in the train, rides along the power conduit as the train travels along its route of travel. The energy is conveyed from the power conduit through the energy collector and ultimately delivered to the power distribution networks and the propulsion controller units on the train. It is well known that voltages spikes are inflicted on the powered systems of a moving train as the energy collector bridges the small gaps between adjacent segments of the power conduit. Nearby radio and TV transmitters, power transmission lines, lightning, cellular telephones and other emissive sources add to the hostile electromagnetic environment in which the electrical/electronic systems of the train operate.
These adverse electrical influences tend to induce unwanted voltages and other spurious noise within the door control trainlines. Unless filtered out by the input circuitry of a DCU, such electrical noise can obscure, or, under the right conditions, even be confused with, the electrical characteristics of the central command signals. Left unfiltered, or otherwise inadequately protected, such noise can conceivably be interpreted by a DCU as a valid incoming central command signal and cause the doors to operate unintendedly. For this reason, transit authorities usually require the door control trainlines to be well filtered and optically coupled to the DCUs.
The input circuitry of prior art DCUs have therefore been designed to include filter circuitry and an optocoupler for each one of the discrete door control trainlines strung from the CDC. Commonly used to couple electronic systems that operate at different voltages, each optocoupler in a DCU provides high elec
Brown Vernal
Horabik Michael
James Ray & Associates
Westinghouse Air Brake Technologies
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