Train Door Control

• Problem:   The 2000 summer games in Sydney spawned a massive overhaul of the commuter rail system. Our customer was selected to provide new door control electronics and a new automated voice message system that would allow computer controlled voice messages to be played over the intercom. An additional requirement was a system retrofit into the existing car wiring.

• Solution:  Group Alpha designed a combined door control/intercom system which communicates over either the DC voltage rail provided within the car, or across the audio twisted pair cabling. The system consists of a master controller located in the driver's cab connected to a system of car controllers that are located within each of the cars. The master controller has mass storage for storing the various audio messages and makes the decisions about what message to play based on the train location. The individual car controllers provide the interfacing to the door position sensors and the door actuators. There is a customer response system consisting of the intercom system and help buttons. This was a very aggressively scheduled project where Group Alpha was able to finish the car integration and system qualification in Sydney in a 3½ month period.

Train Braking System

• Problem:   A major supplier of transit vehicle braking systems needed to update their system electronics to incorporate today's 32 bit microprocessors and modern inter-module communications. The new architecture needed to use as many of the existing peripheral cards as possible. The resulting system needed to have both high availability and high reliability.

• Solution:  A comprehensive analysis of the existing system was conducted and problem areas identified. The result was to redesign their Z-80 based central processor card to use an embedded Intel 386. This provided an order of magnitude improvement in computing bandwidth. The analog I/O subsystems were also redesigned to provide substantial improvement in accuracy and reliability. To implement the communications channel that provides redundancy, a LonWorks based twisted pair (FTT-10) network was chosen. The LonWorks gateways that interfaced the existing electronics to the LonWorks network used a shared memory architecture that required no changes to the system bus. This system was safety critical and all hardware and software were developed under strict development process control and underwent extensive verification and validation. The result was a system that provided a substantial improvement in computational bandwidth and reliability.

Automated Test Equipment

• Problem:   Bay Area Rapid Transit had completed a major refurbishment of its transit vehicles. The car builder had delivered test equipment but the transit authority quickly realized that they needed additional capabilities to improve throughput and test coverage. The requirement was for a test system to test the friction brake electronics both at the sub-system level and to provide for card diagnosis and repair. BART mandated that the new test system utilize National Instruments hardware and software to minimize the impact on training since their personnel were already familiar with those tools.

• Solution:  All of the test hardware (excluding the fixture) was built using National Instrument's standard equipment. A custom fixture was developed that provided equipment protection, signal level shifting, and test connections. The resulting system performs a comprehensive subsystem test to functionally test the braking electronics and to identify problem board assemblies within the braking system. A custom user interface was developed that interfaces to Teststand. It provides enhanced user functions and provides full documentation for the unit under test including: schematics, theory of operation, representative waveforms, and full test documentation. This information is changed based on the context of the test but can be presented at any time by user selection. The complete system was developed in approximately six months with the machine qualified and on line in less than seven months from the time the order was placed.

Gasoline Pump Controller

• Problem:   Our customer was a supplier of submersible pumps for pumping gasoline. The client wanted a pump drive controller that would maintain the pump output pressure so that the volume of gasoline dispensed at the nozzle would be constant regardless of the number of gasoline dispensers operating at that time. Our customer also wanted the controller to be able to perform leak detection tasks and interface to their other equipment across a LonWorks® network.

• Solution:  The final design implemented a 5HP variable speed drive that powers the pump's 3 phase electric motor. A separate pressure transducer was used to measure gasoline pressure. The controller automatically varies the motor speed to maintain a constant head pressure in the gasoline lines. Additionally, the pump controller implemented the leak detection algorithms so that a single package provided the basic pump and leak detection functions needed in a gas station. This product was also required to be "fail safe" and underwent extensive qualification testing at UL to insure that it could be used in this hazardous environment.

Highway Sign Controller

• Problem:   A leading builder of highway signs needed a controller that would allow remote control of the prices shown on interstate gasoline signs. The system needed to be modular since the number of products to be displayed varied from sign to sign and the system required a number of wide area networks to meet specific site needs.

• Solution:  The sign's digits are written on scrolls of material that are positioned by two motors. Each product has a controller that controls the scroll's position so that the proper price is shown on the display. A unique sensor arrangement allows for precise digit positioning even in the harsh environment that these signs are subjected to. The system uses a product controller to control a single product's price for both sides of the sign. The product controllers communicate with the central controller across a twisted pair LonWorks network. The central controller provides system power and acts as a communications interface to a hand held programming device, the POS system used within the gas station and a number of wide area networks. The sign's main controller emulates a Gilbarco gasoline dispenser so that when the POS updates the gas prices at the pump, the sign's display is automatically updated to reflect the change. The system supports several wide area networks.

Automated Meter Reading and Load Shed System

• Problem:   A manufacturer of cable TV systems wanted to provide a system that would allow a utility company to be able to read the power meters and control the power consumption (load control) using their cable plant as the communications medium. The system would communicate to a given house through the CATV system and then be sent to the client devices using the home power lines so that no additional wiring would be required.

• Solution:  We developed a gateway that would interface the CATV signals to either of the prevalent power line technologies used in home automation, LonWorks and CeBUS. Since network management functions would be required, we also developed a set of programming API's that were used to implement the network management software on Unix based servers that were located at the cable plant head end. Within the home the gateway communicates over the power line using either the narrow band LonWorks power line technology or CeBus's spread spectrum technology. Both technologies were required since specific utilities had already made commitments to a particular technology. The system interfaces with Honeywell thermostats and various LonWorks and CeBus electric meters. We also developed load shed devices that could be connected to high energy loads within a home so that the utility could control their consumption.

Precision Conveyor

• Problem:   A major supplier of precision conveyor systems needed to provide a system that would allow very precise movements. The system needed to be modular, easily adaptable to multiple configurations, to comply with some of the prevalent CE control systems and be low cost.

• Solution:  The system provided used a distributed set of stepper motor controls that employed microstepping to achieve both smooth motion and precision movement. These motor drives were connected together within a particular conveyor segment using a CAN communications system. The result was a system that could be allow for flexibility of configuration, reliable operation, and low cost. Several different controllers were developed. A single motor controller for straight line conveyor segments, a dual motor control for two way motion control, and a discrete I/O interface to allow limit switches, optical sensors, and other types of sensors and actuators to be controlled. Finally, we provided a Profibus to CAN gateway that allowed for a given conveyor subsystem to be controlled from a Siemens or compatible PLC.

Hospital Bed Controller

• Problem:   A major supplier of hospital beds needed an embedded controller to provide heating, zoned mattress pressure, and patient orientation. The system needed to be inexpensive, highly reliable and patient safe. Since the bed was used to treat burn and other critical patients, the control systems needed to be free from any system related problem that might endanger a patient.

• Solution:  The system was broken into two separate subsystems: a user interface module that was mounted on the bed's foot rail, and a main control unit that was mounted under the bed. These units communicate between each other across an RS-485 link. The main control unit performs all of the bed control functions. These functions include, head/foot position, blower head pressure, individual zone pressures, and blower air temperature. The user interface module provides the nurse/operator with a keypad and status display. This allows the individual patient parameters (height. weight) to be input so that the beds operating characteristics may be calculated for optimum therapeutic value. Because of the therapeutic nature of the bed, it underwent not only the normal regulatory approvals (UL, CE) but also was subjected to the FDA approval cycle which not only considers the final product but also the rigor and quality of the development process.

Home Automation System

• Problem:   Our customer provided home automation systems that allowed the home owner to electronically control his lighting and other energy consumption. The only problem was that their system used a proprietary communications technology that required new wiring to be pulled within the home so that it might be installed. This severely limited the target market to only new build homes. Further, the system was difficult to maintain and costly.

• Solution:  Group Alpha developed a new system based on LonWorks power line communications. The resulting system consisted of a set of switch and actuator modules, a central memory store that allowed various power/lighting schemes to be preprogrammed and stored, and an input/output bridge that allowed non-LonWorks devices to be interfaced to the system. All of these modules communicated to each other across the power lines within the home eliminating the need for additional wiring. The system provided a communications port that allowed either a local PC or a remote PC attached via modem to be attached and program the system. It also allowed for a remote service rep to be able to connect and diagnose and reconfigure the system. This feature allows the support cost and customer service response time to be substantially reduced. This particular system was one of the first systems introduced that used the Echelon LNS software architecture for network management.