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Team Digital, LLC
SIC24 - Signal & Indicator Controller Application Information |
| General Information: The SIC24 can be used in a number of applications. Various types of signaling systems, Centralized Traffic Control (CTC) panels, semaphore signal motor drive control and controlling Digitrax's SE8C signal board are some types of uses for the SIC24. A computer is not required for controlling signals with the SIC24, but certainly could be used for enhanced operation. To get the best performace from your SIC24, check out Tips for Successful Operation. |
| Known
Problems: 4/29/05 - CV29 does not program correctly when the SIC24 is being programmed in page mode from the program track using a Digitrax system. Workaround - use direct mode programming. SIC24s with this problem can be identified by a single silver mark on the integrated circuit (IC) closest to the bus connectors. |
| Specific Applications: Below is a diagram showing a typical block signal system using a SIC24 and two DBD2s. This is the default signal configuration of the SIC24 as it comes from the factory. |
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| Below is a diagram showing a two track grade
crossing with two bell sound modules using a SIC24 and three DBD2s.
This is an example of the grade crossing setup. This setup is
implemented in
seven simple programming steps which include the option for one or two
track
operation
and the option for a control of one or two bell sound modules. The signal, bell and delayed gate lowering are initiated upon entering an approach. When the island is cleared the signal and bell stop and the gate is raised. If two bell sounds are used, bell 1 is activated when the approach block is occupied and bell 2 takes over when the island block is occupied. |
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| LED connections: The minimum LED current limiting resistor value is 470 ohms. Resistor values of 1K work well with most LEDs. The higher the resistance value, the lower the power supply requirements. |
| Using the SIC24 with Digitrax's SE8C: The SIC24 can be used to control a SE8C signal board. The SE8C uses sequential pairs of switch addresses to control it’s outputs. The switch state, throw or close, is used to differentiate between two of its outputs with the same address. When a SIC24 logic cell becomes true a SE8C switch message is sent. Each logic cell is assigned to one of the SE8Cs outputs. So a SIC24 can control up to 24 sequential SE8C outputs. This represents an address range of 12 SE8C addresses . Note: A SE8C output is used here to indicate one aspect (LED). You can download an Excel spreadsheet from the Support Tools page that gives an example of SIC24 logic cell assignments to control a SE8C. |
| Using the SIC24 with
Digitrax's DB4: The BD4 is a Digitrax block occupancy detector that was designed to work in conjunction with their DS54 or their SE8c. It was not designed to be a stand alone unit. When a block connected to a DB4 input becomes occupied, the respective output turns on causing a voltage to be applied to that output. When the block becauses unoccupied the output tuns off and the voltage drops to zero because of the connection to a DS54 or SE8c. The inputs on these devises have a pull down resistor that loads the output of the DB4. This resistor in conjunction with a capacitor on the DB4 output provides a delay. This delay is the time from when the block become unoccupied until the DB4 output turns off. They also provide the ground or reference point the DB4 requires to operate. The input of a Team Digital SIC24 does not have a pull down resistor nor does it provide the required reference point. Therefore, in order for the DB4 to operate with a SIC24 an interface is required. The best approach is to provide an isolated interface since the DB4 is powered from the track. The diagram below shows connections for one type of optoisolator. If all BD4 outputs are used with a SIC24 an IC with four isolators could be used. The reference point or ground of the BD4 is on pins 2, 4, 6 and 8 of the DS1 10 pin connector. One of these pins needs to be connected to the booster ground or LocoNet (Digirax system) ground. The DB4 outputs are on pins 1, 3, 5, and 7. An output is connected to the emitter diode anode of the optoisolator through a resistor. The emitter diode cathode is connected to one of the DB4 reference point pins. The optoisolator collector is connected to a SIC24 input. The optoisolator emitter (not to be confused with the emitter diode) is connected to the SIC24 ground. If the BD4 is used in conjunction with a DS54 and a SIC24, the BD4 reference should be connected to the DS54 ground as described in the DB4 manual. The diagram shows a 1K (one thousand ohm) resistor connected to the emitter diode anode. The value of this resistor effects the length of the DB4 turn off delay. The higher the value the longer the delay. However, if the value is too high the optoisolator will not work correctly. A 1K resistor provides a very short delay. Depending on the optoisolator you use, you may need to experiment with the resistor value. |
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| 10 Pin Connectors: Both input and output connectors are the same. The Team Digital TSA board plugs directly into these connectors can be used for easy screw terminal connections. Also flat ribbon cable insulation displacement (IDC) type mating connectors can be used. Mating connectors and ribbon cable are available at some Team Digital Dealers and at. Jameco : http://www.jameco.com mating connector part # - 32491 10' flat ribbon cable, gray part # - 135538 10' flat ribbon cable, multicolor part # - 112547 |