Controller Interface Device (CID)
ATACid

Design

The CID design criteria defined by ATAC are:

• easy set up and use
• small in size
• upgradeable
• economically feasible to build

In addition, the CID must include a NEMA TS 2-2003 serial connection and Ethernet connectivity.

Hardware Components

Embedded System

A PC/104 platform from Acrosser Technology, Inc., was selected for its compact form factor and an SDLC serial card from SeaLevel Systems, Inc., was incorporated into the CID. The AR-M9850E embedded system from Acrosser was chosen because it included a power supply, a case, an AR-B1423C embedded computer, and enough room for one expansion card. The AR-B1423C was a good match for the CID because it runs at 133MHz, uses inexpensive SODIMM RAM, has 10/100Base-T Ethernet, VGA video onboard, and DiscOnChip (DOC) support.

Memory

Non-volatile memory is required for the CID to operate as a stand-alone device. This is where CID's operating system and runtime files are stored, allowing it to start up by itself into a fully functional state. A 32MB M-Systems DiscOnChip solid state hard disk was selected since is it uses very little power, essentially unlimited write cycles, is fairly inexpensive, and has error correction and smart buffering. The AR-B1423C main board does not have built-in RAM; therefore, a 64MB SODIMM RAM card was incorporated and is more than adequate.

Software Components

The FreeDOS operating system was selected because it is open source, is actively supported, and available for no cost. For the SDLC serial card, custom drivers were required to meet the CID's requirements. Several software programs were developed to run on the CID and a PC, including CIDserv, CIDlink, and SerUpdt Configuration Utility.

CIDserv Software

The CIDserv software runs continuously on the CID. The program's major task is to keep the controller out of "Diagnostic Flash Mode" by relaying relevant diagnostic information to it. The CIDserv program exchanges status information with a computer through the use of TCP/IP sockets over Ethernet.

CIDlink Software

The CIDlink software was developed to receive and transmit pertinent data with the CID and illustrate this data in graphical form (see illustration). CIDlink, which was developed using Java, is used for verification, as well as testing since detectors may be activated by mouse clicking on the appropriate detector. CIDlink also has a "Virtual Cabinet" feature that allows the CID to act as a Malfunction Management Unit (MMU) and a Terminal and Facilities Bus Interface Unit (T&F BUI). It can also run in a "snoop mode" to observe the controller's signal and detector states. In addition, CIDlink has a “Detector Test” feature that allows users to setup test scenarios for placing calls at various rates and durations for a given period of time.

SerUpdt Serial Server

The SerUpdt Utility is a program written in Visual Basic that allows easy access to the Serial Update function of the CID. Using the RS-232 serial port, the user can set and retrieve the CID's IP address, port number, subnet mask, and gateway. It also allows the user to save and retrieve configuration files on the local PC.

Simulation Interfaces

VISSIM Interface

Interfacing the VISSIM simulation model to the ATACid is achieved through a dynamic link library (DLL) that runs within VISSIM for manipulating the detector and signal data in the simulation. Two configuration files (PUA and VAP) provide important parameters, such as the IP address and detector mapping.

Cube Dynasim Interface

Interfacing the Cube Dynasim simulation model to the ATACid is achieved through a dynamic link library (DLL) that runs within Dynasim for manipulating the detector and signal data in the simulation. A graphical user interface (GUI) developed using JAVA and serves as the application for providing the setup and communication between Cube Dynasim and the traffic controller.

Traffic Controller Configuration

The NEMA TS 2 controller needs to be configured correctly for operation with the CID. It will need to have the appropriate addresses enabled in order to allow it to send the required frames over its Port 1 or SDLC interface. The CID will receive these frames and then emulate the destination device. The CID emulates nine cabinet devices, including the four T&F BIU devices, four Detector BIU devices, and the MMU.

Operation

The CID replies to diagnostic information from the traffic controller, sends signal states from the traffic controller to the PC, and sends detector signals from the PC back to the traffic controller.

When simulation program is running, the traffic logic is executed at the beginning of each time step. The simulation program calls the control program (ATACid interface) to calculate the signal states for the next time step. The CID will regulate the speed of the simulation by pausing the simulation for a specified amount of time, which is based on the number of time steps per simulation second (0.1 to 1.0 seconds). For each time step in, the following tasks are performed:

• Detector information is gathered and sent to the CID,
• Detector information is formatted into NEMA TS 2 protocol and sent to the traffic controller,
• Traffic controller responds to the detector data and provides signal states,
• Signal states are sent to the CID, formatted into the simulation protocol, and relayed to the PC, and
• Signal states are sent to the simulation program and displayed within the simulation network.