SPECIAL SPECIFICATION 6004 Digital Card Rack Inductive Loop Detector Assembly

Transcription

1 2004 Specifications SPECIAL SPECIFICATION 6004 Digital Card Rack Inductive Loop Detector Assembly 1. Description. Furnish and install a digital card rack inductive loop detector assemblies. 2. Materials. Furnish, assemble, fabricate, or install new materials as shown on the plans and in accordance with this item. A. Detector Panel. Provide a fully wired detector input panel as shown on the plans. Mount the detector panel on the rear wall of the cabinet. Size the detector panel for up to 24 loops. Construct panels of in. aluminum. Provide a 3 in. horizontal slot in each corner of the panel for a 0.25 in. mounting bolt. Bring all inputs from the loops through posted X 5/16 in. or 8-32 X 5/16 in. binder screw terminals. Protect each loop pairs with lightning surge suppressers approved for loop inputs by the Departments' Traffic Operations Division Signal Operations Engineer. Mount the suppressers either on the front or behind the panel. Wire the detector harness into the cabinet. Provide additional harnesses as required. Provide the connector end of each harness with 12 in. of vertical and horizontal movement. Arrange connectors so that they may plug into a connector located on either the front or the rear of an amplifier when the face of the amplifier is on the cabinet door side. Provide connection pins as shown in Table 1. Provide a chassis ground bus bar and connect it to the loop lead-in grounds and the cabinet by an insulated braided copper ground strap. Bond the strap to the cabinet. Table 1 Detector Panel Connection Pins Connection Pin No. of Connection Pins External 24 V Power Supply 1 Loop Inputs 48, 2 for Each Detector Logic Ground 1 Spares 0 Chassis Ground Bus 1 Bus B. Detector Unit. Provide detector units in accordance with Article of the NEMA TS-2 Specification, latest edition. Provide digital solid state detector units. Design the units for card mounting and 24 VDC operation. Design the detector units to permit access to the internal components. Provide units that sequentially scan 2 detector channels. Provide units with channels that do not consume more than 100 ma. Provide 8 sensitivity selections for each channel. Provide 3 switch selectable operating frequencies for each channel. Provide an indicator on the front to distinguish between detection, detection delay, and detection extended for each channel

2 Locate the sensitivity, frequency, and mode programming on the front of the unit for each channel. Use thumbwheels or dip switches to input programming settings. Extend and delay time programming may be via dip switches on the circuit board. Provide the following delay and extend output features for each channel. Ensure the delay and extend features function simultaneously. Delay Output - Furnish a variable delay circuit from 0 sec. to 30 sec. with 1 sec. increments. Delay the detector output of a vehicle in the loop for the selected time. Reset the time after the vehicle leaves the loop; however, disable the delay circuit immediately when logic ground is present on Pin 1 for Channel A or Pin 2 for Channel B. Extend Output - Furnish a variable extend circuit from 0 sec. to 7.5 sec. in 0.25 sec. increments. Extend detector actuation after the vehicle leaves the loop. The timing circuit shall reset after the extension has expired; however, the extended circuit shall not be disabled when logic ground is present at Pin 1 or Pin 2 of the connector described herein. Provide the following selectable modes for each channel: Presence Mode - When a vehicle occupies the loop, maintain a detection output for the length of time the vehicle is on the loop and for the time period programmed for the extend output. Pulse Mode - When a vehicle passes over a loop, cause an actuation lasting between 75 msec. and 150 msec. If a vehicle stops in the loop area, detect subsequent vehicles passing over the unoccupied area of the loop within 3 sec. Provide a switch programmable presence time from 1 min. to 15 min. with 1 min. increments. Retune to the environment immediately or upon the loss of green for that phase upon termination of the programmed presence time. Regain 100% of the selected sensitivity within 0.5 sec. of clearing the loop. Provide a 2 x 22 pin PCB edge connector with in. pins centers and gold flashed contacts on the card. Wire each detector unit with the pin assignments as shown in Table 2. Provide a conductivity equivalent of at least 2 oz./sq. ft. of copper on circuit traces. Return to normal channel operation within 2 sec. of electrical power restoration. Provide the units that operate when a resistance to ground on either loop lead is varied from 100 megohms to 50 ohms. Isolate the loop input from the detector circuitry with an isolation transformer for each channel. Provide solid state and optically isolated outputs for each channel. Provide a disable switch for each channel output. If a detector loop circuit becomes open, produce an output until corrected. Produce an output within 5 msec. in response to a 0.13% or greater negative change in loop inductance and terminate the output within 5 msec. when the change is removed

3 Provide lightning protection within the unit. The protection shall enable the amplifier to withstand the discharge of a 10 microfarad capacitor charged to plus or minus 1000 V directly across the detector input pins with no load present and to plus or minus 2000 V directly across either the detector inputs or from either side of the detector inputs to earth ground. Table 2 Detector Unit Pin Assignments Pin No. Function A Logic Ground B Detector Unit DC Supply C External Reset D Channel A Loop Input E Channel A Loop Input F Channel A Output (+) H Channel A Output (-) J Channel B loop Input K Channel B loop Input L Chassis Ground W Channel B Output (+) X Channel B Output (-) 1 Channel A Delay/Extension Input 2 Channel B Delay/Extension Input 6 Detector Unit Address Bit No Detector Unit Address Bit No Detector Unit Address Bit No Data Transmit Output (TX) 21 Data Receive Input (RX) C. Detector Card Rack. Provide a detector card rack in accordance to Article of the NEMA TS-2 Specification, latest edition. Design the detector card rack for 8 detector units. Number the detector unit slots 1 to 8 from left to right on the front of the rack. Fabricate the detector card rack frame with aluminum. Set the slots in a modular fashion such that the PCB edge connectors plug into the rear while sliding between top and bottom card guides. Provide each slot with outward turned mounting flanges. Mate each slot in the rack with a 2 x 22 pin readout card-edge connector with in. pin spacing. Wire each slot as shown in Table 1. Provide key slots between pins B & C and between pins M & N. Secure each card-edge connector with threaded hardware. Design the rack to have wires enter and exit in the lower left rear corner. Label the wires and run them to the detector panel and other parts of the cabinet. Wire loop inputs with shielded twisted pair leads. Connect twisted pair lead grounds to a chassis ground bus bar on the back of the rack. Do not bus the loop outputs together in the rack assembly. Wire and label the detector channels to the Detector Panel as shown in Table

4 Table 3 Detector Channel Labels SLOT CHANNEL DETECTOR No. CHANNEL DETECTOR No. 1 A 1 B 2 2 A 3 B 4 3 A 5 B 6 4 A 7 B 8 5 A 9 B 10 6 A 11 B 12 7 A 13 B 14 8 A 15 B 16 Bus the Logic Ground (Pin A), Detector DC Supply (Pin B), External Reset Inputs (Pin C), Chassis Ground (Pin L), Data Transmit (Pin 19), and Data Receive (Pin 21) to a common point and wire to the Detector Panel. Connect the Data Address Bits No. 0, No. 1, and No. 2 to the logic ground as shown in Table 4. Table 4 Detector Module Communications Address Slot Channels Bit No. 0 Bit No. 1 Bit No OFF OFF OFF ON OFF OFF OFF ON OFF ON ON OFF OFF OFF ON ON OFF ON OFF ON ON ON ON ON Voltage levels: OFF=Not Connected ON=Connected to Logic Ground D. Power Supply. Provide a shelf mounted, enclosed 24 VDC power supply in accordance to Article of NEMA TS-2, latest edition. Furnish on the front panel a power on LED, a power on-off switch, an appropriate sized fuse for the 120 VAC input line, and a metallic shelled connector. Connect the connector to the chassis ground internally and mate with a MS-3106A-18-1SW cable connector or equivalent. Use the connection pin terminations pins as shown in Table 5. Table 5 Power Supply Connection Pin Terminations PIN FUNCTION A B C D E F G H I J AC Neutral Line Frequency Reference AC Line +12 VDC +24 VDC Reserved Logic Ground Earth Ground 12 VAC Reserved

5 Furnish and install 1 power supply cable per power supply in each cabinet. Terminate the wires to bus bars, terminals on the front of the backpanel, detector panels, or connector as appropriate. Use connections with forked spade lugs or otherwise as needed. Cut each individual wire to the length required to reach its connection point. 3. Electronic Components. Provide electronic components in accordance with Special Specification, Electronic Components. 4. Functional Tests. If directed, forward 2 sample detector units, card rack, and power supply to the Department's test facility in Austin for additional testing. The Department's loop detector test facility has the following loop configurations: Four 6 x 6 ft., 3 turn loops connected in series/parallel. Two 6 x 30 ft., 2 turn loops. One 6 x 80 ft., 1 turn loop. One 6 x 30 ft. quadrapole, turn loop. Two high speed 6 x 6 ft., 3 turn loops. Perform testing using the following test vehicles: Class 1 - A standard 10 speed, 26 in. bicycle. Class 2-50 CC motorcycle. Class 3 - Automobile ranging from 1700 to 2000 lb. Class 4 - Standard C-50 tractor-trailer combination. Perform tests on the unit to ensure detection of the test vehicles in all loop configurations with a 100 ft. and 1000 ft. lead-in attached. When testing, adjust sensitivity so no output occurs when the vehicle is more than 36 in. from the perimeter of the loop. Allow no crosstalk between adjacent loops connected to separate channels or loop detector units with or without a vehicle on one of the loops after adjustment. Detect test vehicles traveling in the speed range of 5 mph to 80 mph. In the presence mode, detect test vehicles stopped over a loop. Continuously detect Class 3 and 4 vehicles for the programmed presence time or for at least 30 min. Upon departure of test vehicles from the loop, detect another vehicle after 1 sec. In the pulse mode, test for a single pulse output for test vehicles moving over a loop. Test for normal operation when a resistance to ground on either loop lead is varied from 100 megohms to 50 ohms gradually in a 15 min. period. Test for normal operation as loop integrity is restored in the same time interval. When an induced open circuit in a loop circuit is restored, test for normal operation within 2 sec. or upon termination of the programmed presence time. Connect a 150 picofarad capacitor in parallel across a functioning 6 x 6 loop with a Class 3 vehicle over the loop. Test for normal operation of the channel. Test the lightning protection, by grounding the detector chassis and the detector inputs with a dummy resistive load attached equal to 5.0 ohms

6 If required, perform additional testing in accordance with Article 2, Special Specification, Testing, Training, Documentation, Final Acceptance, and Warranty. 5. Documentation. Provide 2 copies of documentation in accordance with Article 4, Special Specification, Testing, Training, Documentation, Final Acceptance, and Warranty. 6. Warranty. Provide warranty in accordance with Article 6, Special Specification, Testing, Training, Documentation, Final Acceptance, and Warranty. 7. Measurement. This Item will be measured as each Detector Unit, Detector Card Rack, and Power Supply furnished, installed, and tested. 8. Payment. The work performed and materials furnished in accordance with this Item and measured as provided under "Measurement" will be paid for at the unit price bid for "Detector Unit", "Detector Card Rack," or "Power Supply". This price is full compensation for equipment, cables, and connectors; documentation; testing; and labor, materials, training, and equipment