4.2.2 Poll Tree Light Design 4.2.2.1 Components Specifications As stated before, the components’ list will only include the major components for the circuit. Unlike most other circuits, more resistors will be used in the poll tree light. One resistor will be placed before each LED light. In addition, the microprocessor CC2540 will be shared between all other circuits in the finish gate. Component Input Output Voltage (V) Current (A) Voltage (V) Current (A) CC2540 2.0 – 3.6 24 * 10-3 2.0 V – 3.6 V 4 * 10-3 TLC59281 3.0 – 5.5 1 * 10-6 3.0 – 5.5 40 * 10-3 Green LED Light 1.8 – 2.1 20 * 10-3 - - Red LED 1.9 – 2.1 20 * 10-3 - - Yellow LED Light 1.9 – 2.1 20 * 10-3 - - Table 10 Components’ Power Specifications Table 11 shows the pins’ details for each component. This table only shows the pins used for each component for this part of the finish gate. Component Pin # Detail CC2540 P0_0 SIN - Data Line P0_1 SCLK P0_2 Latch P0_3 Sout P0_4 Blank TLC59281 P1 GND P2 Sin – Data Line P3 S P4 Latch P (5,6,7,8) Output P21 Blank P22 Sout P23 IREF P24 Vcc 11 Components’ Output Pins Used
Power Supply Input/Output Power Supply Input (VCC) Verify VCC is between 4.75 VDCand 5.25 VDC at test point DC-DC Converter Output (VDD) Verify VDD is between 3.05 VDC and 3.55 VDC at test TP-Y IR Emitter/Detector IR Emitter Voltage Drop Verify VD is between 0.67VDC and 1.47 VDC at maximum operation point IR Emitter Sink Current Verify maximum current through IR Emitter is between 20 mA and 120 mA Note: Remove jumper for current measurement IR Detector Voltage Drop Verify minimum voltage drop across Detector Diode is 0.67 VDC Verify maximum voltage drop across Detector Diode is 1.8 VDC IR Detector Source Current Verify detector current is between less than 100µA Automatic Gain Circuit Verification of AGC Input reference voltage of 0.5 VDC and verify AGC output increases to maximum gain (2) Input reference voltage of 1.25 VDC and verify AGC output decreases to minimum gain (1) Generally speaking there are three modes of operation which are of relative importance when using photodiodes. They include the photovoltaic mode and photoconductive mode, each having specific benefits. The highest sensitivity can be obtained in the photovoltaic mode of operation, and with null biasing; the dark current offset is negligible. In this mode the detection, incident infrared or ambient light reacts with the photo-sensitive junction of the semiconductor, producing a potential across the device. This potential varies between manufactures but is typically between 0.6 VDC and 1.2 VDC. While this configuration is generally sufficient for most applications it is usually slower than the photoconductive mode. The photoconductive mode is faster but unlike the photovoltaic mode its dark current leakage is not optimal and therefore affects sensitivity. In the simulation circuit below the current source is acting like a photodiode (in conductive mode) which drives the differential input of the amplifier. The static gain of the amplifier is approximately 1.5. Graph 1 below shows the incident current verse voltage of the photodiode, while not obstructed the photodiode will maintain a constant slope before reaching saturation. The midpoint linear region can be used as a reference point for a digital transceiver. This would effectively couple the two systems together and therefore create the detection portion of the speed sensor. The voltage reference
Supply No Power Track Detection System is unplugged Plug in the Track Detection System to 120VAC Main power fuse is blown, damaged, or missing Replace main power supply fuse Servo Motors No Rotation No power or faulty connections Verify power and connections are secure Communication with system main application severed Reset starting gate assembly Servo motor is damaged or malfunctioning Replace servo motor Communications Main Application does not see Track Detection System Main application communications failure Restart software Starting Gate Assembly fails to communicate with the system Power if off Out of Range Invalid Host Starting Gate Verify In range Reset main application Finish Gate Assembly does not respond when commanded Power is off Out of range Invalid Host Reset Finish Gate Verify in range Reset main application Sensors Incorrect Position of TPS Track Position Sensors are in the incorrect locations of track Swap track sections Speed Detection Sensors Max and Min Velocities are incorrect Reconfigure Selection Jumpers Overflow Change Clock Speed Selection Jumpers Speed Sensors not detecting cars Miss alignment Verify alignment Speed Sensor not calibrating Failure to calibrate Verify alignment and reset sensor, re-calibrate manually if needed Position Sensors not calibrating Failure to calibrate Verify no obstructions and recalibrate Table 24 Troubleshooting Table