Sm-6299

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1000 Technology Drive, Pittsburgh, PA 15219 645 Russell Street, Batesburg, SC 29006 SM 6299 ATT-20 Audio Track Transceiver ASTS USA Part Numbers N454052-3901 through N454052-3906  Installation  Operation  Troubleshooting Copyright © 2015 Ansaldo STS USA, Inc. SM 6299, Rev. 2 December 2015 Notices Proprietary Notice This document and the information contained therein are confidential – the disclosure or other communication, copying, reproduction and any use whatsoever is forbidden without the written authorization of Ansaldo STS USA, Inc. Important Notice ASTS USA constantly strives to improve our products and keep our customers apprised of changes in technology. Following the recommendations contained in the attached service manual will provide our customers with optimum operational reliability. The data contained herein purports solely to describe the product, and does not create any warranties. Within the scope of the attached manual, it is impossible to take into account every eventuality that may arise with technical equipment in service. Please consult an ASTS USA local sales representative in the event of any irregularities with our product. ASTS USA expressly disclaims liability resulting from any improper handling or use of our equipment, even if these instructions contain no specific indication in this respect. We strongly recommend that only approved ASTS USA spare parts are used as replacements. © Property of Ansaldo STS USA, Inc., 2015 all rights reserved– the copying, reproduction and use of this work in any form whatsoever is forbidden without the written authorization of Ansaldo STS USA, Inc. 1000 Technology Drive, Pittsburgh, PA USA 15219-3120 645 Russell Street, Batesburg, SC 29006 www.ansaldo-sts.com SM 6299, Rev. 2, December 2015 i Revision History Revision History REV. 0 April 1997 1.0 June 2008 2 ii DATE December 2015 NATURE OF REVISION Initial issue Revised to current template. Updated parts lists and drawings. Incorporated ECO EE-1223 (2/00). Miscellaneous minor grammatical changes. Proof read comments resolved. Revised Figure 1-1 and Figure 6-1 to add R14 and label. Revised Table 6-4 and Figure 6-1 for items 126 and 127. Revised Table 6-5 to correct ATT-20 Unit part numbers. SM 6299, Rev. 2, December 2015 Table of Contents Table of Contents 1. GENERAL INFORMATION ............................................................................................................... 1-1 1.1. Introduction ............................................................................................................................... 1-1 1.2. Physical Description ................................................................................................................. 1-1 1.3. Specifications ............................................................................................................................ 1-1 1.3.1. Power Requirements .................................................................................................... 1-1 1.3.2. Transceiver Characteristics .......................................................................................... 1-2 1.3.3. Receiver Characteristics ............................................................................................... 1-2 1.3.4. Miscellaneous ............................................................................................................... 1-3 2. APPLICATION, INSTALLATION, AND ADJUSTMENTS ................................................................ 2-1 2.1. General ..................................................................................................................................... 2-1 2.2. Shunt Mode Track Circuit Application ...................................................................................... 2-1 2.3. Series Mode Track Circuit Application ...................................................................................... 2-2 2.4. Terminal Connections ............................................................................................................... 2-3 2.5. Mounting Requirements............................................................................................................ 2-3 2.6. General Considerations ............................................................................................................ 2-3 2.7. Shunt Mode Operation.............................................................................................................. 2-4 2.7.1. Shunt Mode Installation ................................................................................................ 2-4 2.7.2. Shunt Mode Adjustment ............................................................................................... 2-5 2.8. Series Mode Operation ............................................................................................................. 2-5 2.8.1. Series Mode Installation ............................................................................................... 2-6 2.8.2. Series Mode Adjustment without Cable Compensating PCB ....................................... 2-6 2.8.3. Series Mode Adjustment with Cable Compensating PCB ............................................ 2-7 2.9. Lightning Protection .................................................................................................................. 2-7 3. FUNCTIONAL DESCRIPTION .......................................................................................................... 3-1 3.1. General ..................................................................................................................................... 3-1 3.2. Shunt Mode Track Circuit ......................................................................................................... 3-1 3.3. Series Mode Track Circuit ........................................................................................................ 3-1 3.4. Detailed Circuit Description ...................................................................................................... 3-1 3.4.1. Transmitter .................................................................................................................... 3-1 3.4.2. Receiver ........................................................................................................................ 3-2 4. FIELD MAINTENANCE ..................................................................................................................... 4-1 4.1. General ..................................................................................................................................... 4-1 4.2. Test Equipment ......................................................................................................................... 4-1 4.3. General Checks ........................................................................................................................ 4-1 4.4. Shunt Mode Checks ................................................................................................................. 4-1 4.5. Series Mode Checks................................................................................................................. 4-3 5. SHOP MAINTENANCE ..................................................................................................................... 5-1 6. PARTS LISTS .................................................................................................................................... 6-1 6.1. ATT-20 Audio Track Receiver Kits ........................................................................................... 6-1 SM 6299, Rev. 2, December 2015 iii Table of Contents 6.2. ATT-20 Audio Track Transceiver Units .................................................................................... 6-1 6.3. ATT-20 Audio Track Receiver Parts List .................................................................................. 6-2 6.4. Cable Compensating PCB Parts List ........................................................................................ 6-5 7. RAIL TEAM AND TECHNICAL SUPPORT ...................................................................................... 7-1 List of Figures Figure 1-1. ATT-20 Dimensions ......................................................................................................... 1-3 Figure 2-1. Shunt Mode Track Circuit Application .............................................................................. 2-1 Figure 2-2. Series Mode Track Circuit Application ............................................................................. 2-2 Figure 2-3. Lightning Arrester and Surge Ripple Filter for Shunt Mode Application .......................... 2-8 Figure 2-4. Lightning Arrester and Surge Ripple Filter for Series Mode Application ......................... 2-9 Figure 3-1. Transmitter PCB Schematic Diagram .............................................................................. 3-3 Figure 3-2. Receiver PCB Schematic Diagram .................................................................................. 3-5 Figure 4-1. ATT-20 Test Circuit for Shunt Mode Application ............................................................. 4-2 Figure 4-2. ATT-20 Test Circuit for Series Mode Application ............................................................. 4-3 Figure 6-1. ATT-20 Parts Illustration .................................................................................................. 6-4 Figure 6-2. ATT-20 Wiring Diagram ................................................................................................... 6-5 Figure 6-3. Cable Compensating PCB Parts Layout and Schematic Diagram .................................. 6-6 List of Tables Table 1-1. Adjacent Frequency Rejection ......................................................................................... 1-2 Table 2-1. Terminal Assignments...................................................................................................... 2-3 Table 2-2. Ring-by Parameters for 0.1 Ohm Shunting ...................................................................... 2-5 Table 2-3. Cable Length vs. Frequency ............................................................................................ 2-6 Table 6-1. ATT-20 Unit Kits ............................................................................................................... 6-1 Table 6-2. ATT-20 Unit (Only) ........................................................................................................... 6-1 Table 6-3. Miscellaneous Application Units ...................................................................................... 6-1 Table 6-4. ATT-20 Unit Parts List ...................................................................................................... 6-2 Table 6-5. ATT-20 Part Tabulation .................................................................................................... 6-3 Table 6-6. Cable Compensating PCB Parts List ............................................................................... 6-5 iv SM 6299, Rev. 2, December 2015 General Information 1. GENERAL INFORMATION 1.1. Introduction This manual provides application, installation and maintenance information for the ASTS USA Audio Track Transceiver, Model ATT-20. The ATT-20 is a short-range transceiver operating in the audio frequency range of 12 to 20 KHz. The high frequency range was chosen to provide sharp block definition. The ATT-20 can be used in applications such as highway crossings, island circuits, switch lock release and general train detection in non-electrified and DC electrified territories. In most cases, insulated joints are not required and track circuits up to 300 feet in length can be realized. Units are available for operation in either shunt mode or series mode applications. 1.2. Physical Description The ATT-20 is a single unit transceiver containing separate transmitter and receiver printed circuit boards, mounted on a common chassis. The chassis is housed in a sheet metal box. The top cover of the unit is the faceplate to which Association of American Railroads (AAR) terminal posts are mounted. 1.3. Specifications 1.3.1. Power Requirements Power Supply Voltage: Maximum Ripple: Load Current: Fuse: 9.8 - 15.2 VDC 1 Vpp 600 mA. 3 / 4 Amp fast blow SM 6299, Rev. 2, December 2015 1-1 General Information 1.3.2. Transceiver Characteristics CAUTION The ATT-20 may be operated from (CPR) supply, batteries floating on regulated supply. Regardless of the filter (ASTS USA N451590-0301) supply and the ATT-20 Transceiver. Shunt Mode Output Voltage: Series Mode Output Voltage: Available Operating Frequencies: Carrier Frequency Tolerance: Modulation Frequency (All Units): Harmonic Output: a constant potential rectifier a CPR, or an electronically supply used, a surge ripple must be used between the 1.0 Vrms (modulated) into a 5-ohm load 0.25 Vrms (modulated) into a 1-ohm load 12.28 KHz, 15.0 KHz, 20 KHz. + 0.5 % 390 Hz + 0.5% -30 dB at second harmonic with 12 ohm load in shunt mode 7 ohm shunt mode; 1 ohm series mode 1.3.3. Receiver Characteristics Sensitivity: Input Impedance: Output Voltage: 70 mVrms (modulated signal) + 14 mV 7 ohms shunt mode, 1 ohm series mode 7.65 VDC into 400 ohms Table 1-1. Adjacent Frequency Rejection ATT-20 Frequency (KHZ) Adjacent Frequency of Concern (KHz) Rejection of Adjacent Frequency (dB) 12.28 15.0 -18.0 15.0 12.28 18.0* 20.0 -30.0 -21.0 -27.0 20.0 15.0 18.0* -44.0 -23.0 * Of concern where joint detectors are used. 1-2 SM 6299, Rev. 2, December 2015 General Information 1.3.4. Miscellaneous Reverse battery protection: Operating temperature range: Maximum block length: Built-in - 40°C to +70°C 300 ft. shunt mode at 3 ohm/1000 ft. ballast; 150 ft. series mode at 3 ohms/1000 ft. ballast. PN-150B, 400 ohm coil, (ASTS USA N322500-701) Refer to Figure 1-1. Recommended Relay: Overall Dimensions: Mounting Hole Dimensions: Weight: Terminal Connections: 2¼" x 8½" 4 lbs., 14 oz. AAR 4 5/8 (REF) 2 1/8 (REF) 2 1/4 (REF) 1 3 5 6 1/16 (REF) 7 4 6 XMT RCV 8 + RELAY - 91 /4 (REF) 2 + BATTERY - 8 (REF) 7 5/8 (REF) TL6 TL5 R14 RAISE LOWER RELAY VOLTS SHUNT MODE UNIT AUDIO TRACK TRANSCEIVER MODEL,ATT-20 PC.NO. SER.NO. FREQ. REV. TL1 TL2 3B3.0001.01 TL4 TL3 Figure 1-1. ATT-20 Dimensions SM 6299, Rev. 2, December 2015 1-3 General Information 1-4 SM 6299, Rev. 2, December 2015 Application, Installation, and Adjustments 2. APPLICATION, INSTALLATION, AND ADJUSTMENTS 2.1. General This section provides information on the application of the ATT-20, as well as installation and adjustment procedures for the ATT-20 and related equipment. It is also critical that this section be read in its entirety prior to any application considerations. 2.2. Shunt Mode Track Circuit Application In this application, the transmitter output and receiver input are connected by cable directly to the rails. The connection is made through surge protectors by twisted line pairs as shown in Figure 2-1. The point at which the transmitter wires are connected defines one end of the track circuit. While the other end of the track circuit is defined by the receiver connections to the track. The receiver detects the presence of a train by the loss of the audio frequency signal that is shunted away by the train axle. The shunt mode of operation is defined as a vital application. 300 FEET RING-BY MAX. USSP-21 USSP-21 1 3 1 3 2 4 2 4 1 3 5 7 2 4 6 8 HARD-WIRE SHUNT USED DURING SET-UP TO BATTERY ATT-20 3B3.0002.01 TWISTED PAIR Figure 2-1. Shunt Mode Track Circuit Application SM 6299, Rev. 2, December 2015 2-1 Application, Installation, and Adjustments 2.3. Series Mode Track Circuit Application In this application, the transmitter and receiver are wired in sequence via a jumper on the ATT20 unit. This jumper connects transmitter output terminal 4 to the receiver input terminal 6. The remaining transmitter output lead (terminal 3) and the remaining receiver lead (terminal 5) are twisted as a pair and each is connected to its respective rail (see Figure 2-2). The presence of a train axle across the rails completes the series signal path, thus detecting the approach of a train. The series mode of operation is a non-vital application. 75 FEET 60 FEET “O” OHM SHUNT 1 3 1 3 12V BATTERY 2 2 USSP-21 4 4 5 7 6 8 ADJUSTMENT SHUNT _ ATT-20 + CABLE COMPENSATING PCB L1 3B3.0003.00 1 C1 2 TWISTED PAIR T2 T3 T1 CT Figure 2-2. Series Mode Track Circuit Application 2-2 SM 6299, Rev. 2, December 2015 Application, Installation, and Adjustments 2.4. Terminal Connections AAR type terminals are located on the top of the unit for making external connections. Refer to Table 2-1 for terminal assignments. Table 2-1. Terminal Assignments Terminal No. Description 1 + Battery 2 - Battery 3 Transmitter Lead 4 Transmitter Lead 5 Receiver Lead 6 Receiver Lead 7 + Relay 8 - Relay Internal wiring is accessed through a hole with a grommet around it in the faceplate. Also located on the faceplate is an access hole which is intended for setting transmitter gain. This is a simple adjustment and can be accomplished with a screwdriver. 2.5. Mounting Requirements A convenient mounting bracket, which is an integral part of the case, provides four holes spaced 2-1/4 x 8-1/2 apart to facilitate wall, shelf or rack mounting. 2.6. General Considerations • Track leads to the transmitter and receiver must be a #9 AWG or heavier twisted pair. • Power supply must be 9.8 - 15.2 VDC and capable of supplying 1 ampere. A surge ripple filter (ASTS USA Part No. N451590-0301) must be used between any supply and the ATT-20. Power supply ripples must not exceed 1.0 Vpp. • Use higher frequency units when less ring-by is desired. • Provide lightning protection per Section 2.9. • The relay recommended to be used with ATT-20 is a vital PN-150B, ASTS USA No. N322500-701, 400 ohm, plug-in type. SM 6299, Rev. 2, December 2015 2-3 Application, Installation, and Adjustments 2.7. Shunt Mode Operation CAUTION When using the shunt track circuit configuration, do not repeat the use of the same frequency unless circuits are isolated by at least two (2) insulated points. Where less ring-by is desired, keep the track circuit length to a minimum and use the shortest possible track leads. Refer to Figure 2-1 and Table 2-2 for shunt track circuit application. 2.7.1. Shunt Mode Installation Refer to Figure 2-1 and proceed as follows to install the ATT-20 in shunt mode application: 1. Connect transmitter terminals 3 and 4 to terminals 3 and 4 of the USS-21 surge suppressor. Continue the cabling to the track from terminals 1 and 2 of the USSP-21. Repeat the above procedure for cabling receiver input terminals 5 and 6 to the rails. All transmitter and receiver cables must be #9 AWG or heavier and used as a twisted pair. Ensure the combined lengths of the transmitter and receiver cables do not exceed 500 ft. Also, do not exceed block lengths of 300 ft. 2. Connect terminals 7 (relay +) and 8 (relay -) to the relay. The recommended relay to be used with the ATT-20 is a PN-150B, 400 ohm plug-in type, ASTS USA Part No.: N322500-701. 3. If the ATT-20 is to receive its DC power from a battery or constant potential rectifier supply (CPR) or an electronically regulated supply, a surge ripple filter (Part No. N451590-0301) must be used as follows: a. Connect terminals 1 (+) and 2 (-) of the ATT-20 to respective "+DC" and "-DC" terminals of the ripple filter. See Figure 2-3. b. Jumper terminals 2 to N on the ripple filter and cable terminals B (positive) and N (negative) to their respective battery bus or supply terminals. Lightning arrestor USGA N451552-0101 should be across ripple filter terminals B and N. Refer to Section 5 for the details on lightning protection. 4. If the ATT-20 is to be powered from an electronic supply, this supply should be capable of delivering 1.0 ampere at 12 VDC (on the ATT-20 side of the surge ripple filter) and be dedicated to the ATT-20 that it is powering. 2-4 SM 6299, Rev. 2, December 2015 Application, Installation, and Adjustments 2.7.2. Shunt Mode Adjustment Proceed as follows to adjust the ATT-20 in a shunt mode installation: 1. Connect a hard-wire shunt across the rails outside of the defined block at the desired ringby distance from the ATT-20 receiver track connections (terminals 5 and 6). Table 2-2 shows typical ring-by parameters for 3.0 ohm/1000 ft. ballast and 0.1 ohm adjustment shunt. Note The adjustment shunt mentioned below is not a hard-wire shunt. The resistance of the adjustment shunt must accurately represent the desired shunting sensitivity. 2. Adjust the ATT-20 transmitter output level through the access hole in the top cover until the relay is energizes. 3. Remove the hard-wire shunt from the rails. 4. Place an adjustment shunt across the rails at the receiver connection (not the ring-by distance). The relay should deenergize. A compromise between the shunting sensitivity (adjustment shunt) and ring-by distance will be achieved per application. 5. Remove the adjustment shunt from the rails. The adjustment procedure is complete. Table 2-2. Ring-by Parameters for 0.1 Ohm Shunting Typical Minimum Ring-By (Ft.) Track Length (Ft.) Total Cable Length (Ft.) 12.28 KHZ 15.0 KHz 20.0 KHz 100 100 300 11 14 10 14 9 13 500 19 19 19 200 18 18 17 300 21 21 22 500 29 29 33 300 30 30 33 400 35 36 41 500 40 43 52 200 300 2.8. Series Mode Operation Series track circuit locations operating at the same frequency must be separated by at least two insulated joints. A typical series mode application would be at a switch lock. SM 6299, Rev. 2, December 2015 2-5 Application, Installation, and Adjustments 2.8.1. Series Mode Installation Refer to Figure 2-2 and proceed as follows to install the ATT-20 in a series mode application: 1. Connect a jumper strap between terminals 4 and 6 on the ATT-20 when the total single conductor cable length from the ATT-20 to the track is less what appears in Table 2-3 below. If the cable length is exceeded, connect terminals 4 and 6 on the ATT-20 to terminals 1 and 2, respectively, of the cable compensating circuit board (N131002-01). The cable compensating PCB is part of an ATT-20 kit. See Section 6.1 for part numbers. Table 2-3. Cable Length vs. Frequency Suffix No. N451052- Frequency (KHz) Total Cable Length (Length x 2 cond.) Jumper from Cable Compensating PCB to Terminal: -3904 -3905 12.28 15 < 75 feet < 50 feet T3 T2 -3906 20 < 25 feet T1 2. Connect terminals 3 and 5 to terminals 3 and 4 of the USSP-21 surge suppressor. 3. Connect terminals 1 and 2 of the USSP-21 to the track at a point 75 feet from the switch points. All cabling from the ATT-20 to the track must be #9 AWG or heavier twisted pair. 4. Connect terminals 7 (relay +) and 8 (relay -) to the relay. The recommended relay to be used with the ATT-20 is a PN-150B, 400 ohm, plug-in type, Part No. N322500-701. 5. If the ATT-20 is to receive its DC power from a battery, constant potential rectifier supply (CPR), or an electronically regulated supply, a surge ripple filter (Part No. N451590-0301) must be used as follows: • If the ATT-20 is to be powered from an electronic supply, this supply should be capable of delivering 1.0 ampere at 12 VDC (on the ATT-20 side of the surge ripple filter) and be dedicated to the ATT-20 it is powering. 2.8.2. Series Mode Adjustment without Cable Compensating PCB Proceed as follows to adjust the ATT-20 in a series mode, without cable compensating PCB installation: 1. Connect a hardwire shunt across the rails 65 feet from the ATT-20 track connections. 2. Adjust the ATT-20 transmitter output level through the access hole in the top cover until the relay is just energized. 3. Remove the hardwire shunt from the rails. The adjustment procedure is complete. 2-6 SM 6299, Rev. 2, December 2015 Application, Installation, and Adjustments 2.8.3. Series Mode Adjustment with Cable Compensating PCB Proceed as follows to adjust the ATT-20 in a series mode, with cable compensating PCB installation: 1. Place a zero ohm shunt across the track connections at the feed end. 2. Connect an AC voltmeter (Vrms) across terminals 5 and 6 on the ATT-20. 3. On the cable compensating PC board, adjust the slug in pot core inductor L1 until the voltmeter indicates a maximum. Note Depending on cable length, peaking of the signal might not be possible. After adjustment of inductor, place a small amount of RTV in the pot core adjuster area. 4. Remove the zero ohm shunt. 5. Connect a hardwire shunt across the rails 65 feet from the ATT-20 track connections. 6. Adjust the ATT-20 transmitter output level through the access hole in the top cover until the relay is just energized. 7. Remove the hardwire shunt from the rails. The adjustment procedure is complete. 2.9. Lightning Protection Block wiring diagrams showing the wiring of surge and ripple protection for the ATT-20 in both the shunt and series modes of operation appear in Figure 2-3 and Figure 2-4, respectively. Two lightning protection devices are to be used with the ATT-20. The track connections will be made through a USSP-21 secondary surge protection and the battery power supply line will be protected by a surge ripple filter that uses a USG-A lightning arrester across the power bus terminals. The USSP-21 surge protector is wired to permit line-to-line protection using a low voltage arrester and line-to-ground protection using high voltage arresters. Internal circuitry of the USSP-21 also includes series line inductors as well as back-to-back Zener diodes for suppression of low voltage transients. The ASTS USA part no. is N451552-0525. The surge ripple filter consists of a series line inductor and a four-terminal capacitor with a selenium suppressor diode across its terminals. The four-terminal capacitor guarantees loss of power to the load should one of the capacitor leads or plates open. SM 6299, Rev. 2, December 2015 2-7 Application, Installation, and Adjustments The line-to-line arresters used across terminals 1 and 2 of the USSP-21 and terminals B and N of the Surge Ripple Filter are USG-A N451552-0101. The line-to-ground arresters used across terminals 1 and 5, 2 and 6 of the USSP-21are USG-A N451552-0201. TO TRACK TO TRACK 1 USSP-21 5 2 1 6 5 2 USSP-21 3 4 3 3 4 5 TRANSMITTER 6 4 6 RECEIVER ATT-20 1 + DC + DC SURGE RIPPLE FILTER (N451590-0301) 7 2 + DC 8 RELAY _ _ DC 4 2 B 3B3.0004.01 _ N TO BATTERY OR POWER SUPPLY LIGHTNING ARRESTER PART NO. N451552-0101 TWISTED PAIR Figure 2-3. Lightning Arrester and Surge Ripple Filter for Shunt Mode Application 2-8 SM 6299, Rev. 2, December 2015 Application, Installation, and Adjustments TO TRACK 1 5 2 USSP-21 3 3 8 4 6 4 5 RECEIVER TRANSMITTER ATT-20 1 3B3.0005.01 + 2 DC _ + DC _ 8 7 DC + RELAY _ DC 4 2 B N TO BATTERY OR POWER SUPPLY TWISTED PAIR LIGHTNING ARRESTER PART NO. N451552-0101 Figure 2-4. Lightning Arrester and Surge Ripple Filter for Series Mode Application SM 6299, Rev. 2, December 2015 2-9 Application, Installation, and Adjustments 2-10 SM 6299, Rev. 2, December 2015 Functional Description 3. FUNCTIONAL DESCRIPTION 3.1. General The transmitter produces an output signal in the high audio frequency range and is sine wave modulated to provide noise immunity. First, the receiver detects the modulation information signal. It then amplifies and rectifies this signal to provide a DC output which drives the relay coil. The functional description of the ATT-20 applied to the shunt track circuit is covered in Section 3.2. Section 3.3 covers the series mode track circuit. 3.2. Shunt Mode Track Circuit As illustrated in Figure 2-1, the transmitter output and receiver input are cabled directly to the rails. The point at which the transmitter wires are connected defines one end of the track circuit. The other end of the track circuit is defined by the receiver connections to the track. The receiver detects the presence of a train by the loss of the audio frequency signal which is shunted away by the train axle. The shunt mode of operation is defined as a vital application. 3.3. Series Mode Track Circuit As illustrated in Figure 2-2, the transmitter and receiver are wired in series via a jumper located on the ATT-20 unit. This jumper connects the transmitter output terminal to the receiver input terminal. The remaining transmitter output lead and the remaining receiver lead are twisted as a pair with each is connected to its respective rail. The presence of a train axle across the rails completes the series signal path, thus detecting the presence of a train The series mode of operation is a non-vital application. 3.4. Detailed Circuit Description 3.4.1. Transmitter The transmitter circuit diagram is shown in Figure 3-1. Transistor Q1 and its associated circuitry comprise the modulation oscillator which produces 390 Hz. A constant signal level is maintained by Zener diode D1. Transistor Q2 buffers the modulation oscillator. Transistor Q7 and its associated circuitry comprise the carrier frequency oscillator. Selection of capacitor C3 determines the carrier frequency. Transistors Q3, R8 and R13 mix the carrier and modulation signals. Resistor R14 provides gain control. Inductor L1, capacitor C5, and resistor R17 form a bandpass filter which allows the modulated carrier to pass unaltered by low frequency or higher order harmonic disturbances. Resistor R15 and R19 form a voltage divider which sets the bias for transistor Q4. Capacitor C12 bypasses resistor R19. Transistors Q4, Q5, Q6 and Q8 make up a unity gain amplifier with low output impedance. Diodes D4, D5, D6 and D8 - along with resistors R20 and R21 - serve to SM 6299, Rev. 2, December 2015 3-1 Functional Description temperature compensate and bias both transistors Q5 and Q6. C13 is a bypass capacitor. Capacitor C6 and the primary of T3 couple the signal to the output circuitry. Inductor L5, jumper J2 and capacitor C9 from the shunt mode output, provide an output impedance of 7 ohms. Inductor L6, jumper J1 and capacitor C9 form the series mode output provide an output impedance of 1 ohm. Diode D7 prevents damage from reverse battery connection. Fuse F1 prevents damage from an overcurrent condition. Inductors L2, L3 and capacitor C11 provide RFI rejection. Capacitors C7 and C10 filter the power bus. 3.4.2. Receiver The receiver circuit diagram is shown in Figure 3-2. Capacitor C1, transformer T1 and resistor R1 form a medium Q input filter. Jumper positions should be J1 and J3 for both shunt and series mode boards. The input impedance is primarily determined by R1 (Shunt boards = 7 ohms, series boards = 1 ohm). Transistors Q1 and Q2 form a Darlington pair emitter follower which buffers the input signal. Resistor R4 and Zener diode D10 provide a fixed bias voltage for Q1 and Q2. Inductors L3 and L4; capacitor C3, C4 and C5; and resistors R6 and R7, together form a high Q bandpass filter. Diode D1 demonstrates the signal. Resistor R8 and capacitor C6 filter the carrier frequency. Transistor Q3 and its associated circuitry form an emitter follower to buffer the demodulated signal. Resistor R13 is selected to provide an input sensitivity of 70 mVrms (modulated signal). Transformer T2 and capacitor C9 form the demodulated filter. Transistors Q4 and Q5 are configured as an emitter follower which buffers the demodulated signal. Capacitors C11 and C12, along with diode D3 and D4, form a voltage doubler. This doubler produces a negative DC voltage which drives a level detector. The level detector consists of resistor R17 and diode D5. Once in conduction, D5 provides the feedback path necessary for Q6 and its associated circuitry to behave as an oscillator. The oscillator frequency is approximately 25 KHz. The output of the oscillator is buffered by transistor Q7 and Q10. Transistors Q8 and Q9 amplify the signal. Diodes D7 and Q11, along with capacitors C17 and C8, form a voltage doubler. They also rectify and filter the signal to provide a negative DC voltage to drive an external relay. The Q11 circuit decreases relay drop away time in lieu of the standard 2-diode voltage doubler circuit. Inductors L1, L2, L6, and L7 (along with capacitors C19 and C7) provide RFI rejection. Capacitor C10 filters the power bus. 3-2 SM 6299, Rev. 2, December 2015 Functional Description F1 TP4 B+ 1-1/2 A TL1 L3 C11 .01uf D7 VSK130 TP2 POWER TL2 R1 1K 332T R15 1K 1K T1 R2 820K Q2 2N3117 R6 1328T Q1 2N3117 + C10 C1 1.0uf .01uf C7 R3 390K R4 5.1K D2 1N914 R5 10K C2 .15uf R7 10K R8 10K 47uf TP3 D1 LVA450 Q4 2N3117 R13 33K R14 1M R16 C4 .22uf Q8 2N2270 10K Q5 2N6059 L1 D4 1N914 R22 3.6M R10 R9 3.3K 5.1K R17 TAB. 26T R23 C5 TAB. 10K R20 0.5 C13 6.8uf D8 1N914 Q7 2N3964 R21 0.5 C6 15T 26T L6 100uf SHUNT J2 C8 .47uf J1 COM C9 .47uf TL6 TRACK SERIES 6T R12 T2 258T R11 8.2K L5 T3 D5 1N914 TP1 Q3 2N3117 470K C3 TAB. C12 47uf R19 3.0K D3 1N914 D6 1N914 Q6 2N6052 TL5 TRACK R18 470 TL3 L2 TP5 B- 3B3.0010.00 TL4 GND Figure 3-1. Transmitter PCB Schematic Diagram SM 6299, Rev. 2, December 2015 3-3 Functional Description 3-4 SM 6299, Rev. 2, December 2015 Functional Description TL3 POWER C + TL1 L1 C1 T1 TRACK TAB. J4 TAB TP2 TP6 R6 C3 C4 D1 TBD TAB. TAB. 1N4936 Q2 2N2270 R10 R5 100 1N4003 TAB L3 R13 TBD 1N914 R8 200K C6 .0033uf C9 .15uf Q5 2N2270 1ST D2 C5 L4 TAB R14 1K 1K .02uf R7 TAB. D9 C19 .01uf C8 C10 47uf Q4 2N3117 Q3 2N3117 680 2ND 1ST TP1 Q1 2N3117 R2 J3 R11 47K T2 2ND R12 10K TAB. + C11 D4 10uf 1N4003 A TP3 R16 100 R15 1.5K D3 1N4003 + C12 10uf J2 TL2 L2 D10 R1 B TRACK TAB J1 LVA462 R4 10K C C15 .1uf R17 R22 10K A C 1.8K R23 300 R18 240K R20 1ST C13 .027uf R26 2ND 2K R19 270K Q10 2N2270 C16 .027uf C14 .56uf R21 2.4K TP5 Q8 2N3053 R25 24K C17 D6 1N4003 TP4 TL5 TL4 L6 + B Q7 2N3117 T3 2K D5 LVA450 R24 20K Q6 2N3117 RELAY - B GND 6.8uf Q9 2N4037 D7 VSK130 R3 2K C18 5uf C7 .01uf D11 1.5KE16CA TL6 3B3.0009.00 R27 680 R28 20 L7 RELAY + Q11 2N4037 Figure 3-2. Receiver PCB Schematic Diagram SM 6299, Rev. 2, December 2015 3-5 Functional Description 3-6 SM 6299, Rev. 2, December 2015 Field Maintenance 4. FIELD MAINTENANCE 4.1. General The following procedures may be used to check the ATT-20 at its field installation. These procedures should also reveal whether the fault is in the ATT-20 or a related unit or circuit. If fault lies with the ATT-20, the ATT-20 should be replaced with a new unit. When installing the new unit, please make certain to follow all installation procedures outlined in Section 2. Replacement units may be obtained through the ASTS USA Sales Office. 4.2. Test Equipment • True RMS reading DMM (Fluke 8010A or equivalent). • 5.0 ohm, 5 watt resistor 1% • 1.0 ohm, 5 watt resistor 1% 4.3. General Checks Proceed as follows to perform a general check of the ATT-20 unit before performing a series mode or shunt mode check: 1. Inspect all leads for breaks and loose terminal connections. 2. Check power supply voltage at terminals 1 (+) and 2 (-). The voltage should be 12 VDC nominal (9.8 minimum to 15.8 VDC maximum). Ripple voltage should not exceed 1.0 Vpp. 3. Check the fuse on the transmitter circuit board. If it is open, replace it with a 3.4 Amp fast-blow fuse. If the fuse is intact, disconnect the transmitter and receiver track connections at the unit. To test for proper operation in the shunt mode, refer to Section 4.4. To test for proper operation in the series mode, refer to Section 4.5. 4.4. Shunt Mode Checks Proceed as follows to perform a shunt mode check: 1. Connect the ATT-20 as shown in Figure 4-1. 2. Turn the RELAY VOLTS potentiometer fully clockwise. If the relay energizes, proceed to step 3. If the relay does not energize, check the relay connections for proper polarity and open circuits. If the same relay connections are good, replace the ATT-20 with one of a unit of the same operating frequency and repeat steps 1 and 2. If the relay still does not energize, replace it with another PN-150B, 400 ohm coil (ASTS USA Part No. N322500701). SM 6299, Rev. 2, December 2015 4-1 Field Maintenance 3. If the relay does energize, disconnect the resistor between terminals 3 and 5, and disconnect the jumper between terminals 4 and 6. Measure the open circuit voltage across terminals 3 and 4. The voltage should be equal to or greater than 2.3 Vrms. If this voltage should be equal to or greater than 2.3 Vrms, reconnect the resistor between terminals 3 and 5, and reconnect the jumper between terminals 4 and 6. Adjust the transmitter level so that it just energizes the relay. Measure the voltage across terminals 5 and 6 (receiver input). This voltage should be 70 mVrms + 14 mVrms. If not, replace the ATT-20 unit. ATT-20 + 1 3 5 5.0 OHM 12V BATTERY _ 2 4 7 1.0 OHM 6 8 3B3.0011.00 _ + PN150B RELAY Figure 4-1. ATT-20 Test Circuit for Shunt Mode Application The tests performed in Section 4.4 verify proper operation of the ATT-20 unit in a shunt mode application. If the track circuit installation still does not work properly, troubleshoot the cabling, connections, and peripheral equipment associated with the track circuit. 4-2 SM 6299, Rev. 2, December 2015 Field Maintenance 4.5. Series Mode Checks Proceed as follows to perform a series mode check: 1. Connect the ATT-20 as shown in Figure 4-2. 2. Turn the RELAY VOLTS potentiometer fully clockwise. If the relay energizes, proceed to step 3. If the relay does not energize, check the relay connections for proper polarity and open circuits. If the relay connections are good, replace the ATT-20 with a unit of the same frequency and then repeat steps 1 and 2. If the relay still does not energize, replace the relay with another PN-150B, 400 ohm coil (ASTS USA Part No. N322500-701). 3. If the relay energizes, disconnect the resistor between terminals 3 and 5, and disconnect the jumper between terminals 4 and 6. Measure the open circuit voltage across terminals 3 and 4. This voltage should be greater than or equal to 0.4 Vrms. Replace the ATT-20 if the open circuit voltage is less than 0.4 Vrms. If the voltage is greater than or equal to 0.4 Vrms, reconnect the resistor between terminals 3 and 5, and reconnect the jumper between terminals 4 and 6. Adjust the transmitter level to just energize the relay. Measure the voltage across terminals 5 and 6 (receiver input). This voltage should be 70 mVrms + 14 mVrms. If not, replace the ATT-20 unit. The tests performed in Section 4.5 verify proper operation of the ATT-20 unit in a series mode application. If the track circuit installation still does not work properly, troubleshoot the cabling, connections, and peripheral equipment associated with the track circuit. ATT-20 + 1 3 5 7 6 8 1.0 OHM 12V BATTERY _ 2 4 _ + 3B3.0012.00 PN150B RELAY Figure 4-2. ATT-20 Test Circuit for Series Mode Application SM 6299, Rev. 2, December 2015 4-3 Field Maintenance 4-4 SM 6299, Rev. 2, December 2015 Shop Maintenance 5. SHOP MAINTENANCE ASTS USA recommends that faulty ATT-20 units be returned to the factory for shop level testing and repair. Both the transmitter and receiver PCB’s must undergo special testing, calibration, and component replacement (per frequency) procedures. See Section 7 for contact information. SM 6299, Rev. 2, December 2015 5-1 Shop Maintenance 5-2 SM 6299, Rev. 2, December 2015 Parts Lists 6. PARTS LISTS 6.1. ATT-20 Audio Track Receiver Kits Each kit consists of a complete ATT-20 unit for series mode application and the Cable Compensating PCB. Table 6-1 lists the kit part numbers. Table 6-1. ATT-20 Unit Kits Kit Part No, ATT-20 Unit Cable Compensating PCB Application X451052-3907 N451052-3904 N13100201 Series X451052-3908 N451052-3905 N13100201 Series X451052-3909 N451052-3906 N13100201 Series 6.2. ATT-20 Audio Track Transceiver Units The ATT-20 unit part numbers and descriptions are listed in Table 6-2. Table 6-3 lists other devices that are used in certain ATT-20 applications. Table 6-2. ATT-20 Unit (Only) Part No. Frequency (KHz) Application N451052-3901 12.28 Shunt N451052-3902 15.00 Shunt N451052-3903 20.00 Shunt N451052-3904 12.28 Series N451052-3905 15.00 Series N451052-3906 20.00 Series Table 6-3. Miscellaneous Application Units Item Part Number Secondary Surge Protector USSP-21 N451522-0525 Between ATT-20 unit and track Surge Ripple Filter N451890-0301 Between ATT-20 power input and DC source Lightning Arrestor N451552-0101 Across battery terminals of Surge Ripple Filter Cable Compensating PCB SM 6299, Rev. 2, December 2015 Application N1310-0201 6-1 Parts Lists 6.3. ATT-20 Audio Track Receiver Parts List Table 6-4 and Table 6-5 contain parts lists for ATT-20 Audio Track Transceiver units N4510523901 through -3906. Refer to Figure 6-1 for the component locations. The internal wring diagram is shown in Figure 6-2. Table 6-4. Item 6-2 ATT-20 Unit Parts List Part Number Description Quantity 5 Refer to Table 6-5 CHASSIS 1 EA 10 R438872 COVER 1 EA 15 Refer to Table 6-5 PCB,ATT-20 TRANSMITTER 1 EA 20 Refer to Table 6-5 PCB,ATT-20 RECEIVER 1 EA 25 M181829 4 WAY BLOCK 1 EA 30 J5252720110 SCREW-10-32X5/8 SST 2 EA 35 J047733 WASHER,10 STEEL LOCK MED 2 EA 40 J048172 NUT,10-32 HEX STEEL 2 EA 45 J047818 WASHER,17/64X9/16 COP 40 EA 50 J480300 NUT,14-24 HEX BRASS NP 16 EA 55 J480301 NUT,14-24 HEX BRASS 16 EA 60 J525111 SCREW,8-32X1-1/4 RD HD STEEL 4 EA 65 J047714 WASHER-8 SHPRF LK SS 4 EA 70 J048166 NUT,8-32 HEX STEEL 4 EA 75 M337854 INS TUBING 8 EA 80 J052686 SCREW,8X3/8 RD HD 4 EA 85 J730041 TERM-PRE-INSUL, DIAGR 8 EA 90 (not shown) J078399 BAG-PLASTIC,#60F-0406 1 EA 100 (not shown) S705.11 WIRE, TAG 12" BUNDLE 1 EA 105 J075415 GROMMET, RUBBER 3/8"ID 1 EA 110 (not shown) A774169 TUBING.HT SHRINK 3/16ID 1 FT 115 (not shown) A774184 TUBING SHRINK FIT 1/16 1 FT 120 (not shown) A434083 CA-1 TW. PR. SHELDD. MIN 6 FT 125 J703310 CABLE TIE, SELF LOCKING 5 EA 126 J0759550056 LABEL, WHITE, POLY, #M-787, OILTAK 1 EA 127 J7928220039 RIBBON, THERMAL TRANSFER, R6007 1 EA SM 6299, Rev. 2, December 2015 Parts Lists Table 6-5. ATT-20 Part Tabulation CHASSIS Item 5 XMITTER PCB Item 15 RCVR PCB Item 20 ATT-20 Unit Freq. (KHz) Application N451052-3901 12.28 Shunt R451053-6302 N451605-6402 N451605-6502 N451052-3902 15 Shunt R451053-6302 N451605-6403 N451605-6503 N451052-3903 20 Shunt R451053-6302 N451605-6404 N451605-6504 N451052-3904 12.28 Series R451053-6303 N451605-6405 N451605-6505 N451052-3905 15 Series R451053-6303 N451605-6406 N451605-6506 N451052-3906 20 Series R451053-6303 N451605-6407 N451605-6507 SM 6299, Rev. 2, December 2015 6-3 Parts Lists TL5 TL6 TL6 TL5 75 70 65 60 15 COMP. SIDE 20 COMP. SIDE 55 50 1 5 3 7 30 35 40 TL6 TL5 45 2 + BATTERY - 4 6 XMT RCV 8 + RELAY - 85 25 R14 LOWER RAISE RELAY VOLTS SHUNT MODE UNIT AUDIO TRACK TRANSCEIVER MODEL,ATT-20 PC.NO. SER.NO. FREQ. REV. 5 TL1 TL4 TL3 TL2 3B3.0006.01 80 10 Figure 6-1. ATT-20 Parts Illustration 6-4 SM 6299, Rev. 2, December 2015 Parts Lists TL1 B+ TL3 B- TL6 TRACK TL5 TRACK 1 3 5 7 2 4 6 8 R R B SHIELD R B SHIELD R B B SHIELD R TL2 POWER TL4 RELAY + TL6 TL5 TRACK TL1 TRACK TL2 POWER TL3 GND TL4 SHIELD B GND RELAY - 3B3.0007.00 SHIELD XMITER PCB RCVR PCB Figure 6-2. ATT-20 Wiring Diagram 6.4. Cable Compensating PCB Parts List Refer to Table 6-6 and Figure 6-3 for Cable Compensating PCB, ASTS USA N13100201, parts, parts layout, and schematic diagram. Table 6-6. Item Cable Compensating PCB Parts List Part No. Description Quantity 5 N381621 BLOCK, TERM 1 EA 10 N13100101 PCB, CABLE COMPEN 1 EA 15 J047818 WASHER,17/64X9/16 COP 2 EA 20 J5000970128 SCR-SST 1/4-20X1-3/4 2 EA 25 J4751200112 WASHER, SST PLATE NO1/4 2 EA 30 J4751210111 WASHER, SST LOCK NO1/4 2 EA 35 J4802110108 NUT,1/4-20 SST HEX 2 EA SM 6299, Rev. 2, December 2015 6-5 Parts Lists Figure 6-3. Cable Compensating PCB Parts Layout and Schematic Diagram 6-6 SM 6299, Rev. 2, December 2015 RAIL Team and Technical Support 7. RAIL TEAM AND TECHNICAL SUPPORT The Rapid Action Information Link Team (RAIL Team) is a group of experienced product and application engineers ready to assist you to resolve any technical issues concerning this product. Contact the RAIL Team in the United States at 1-800-652-7276 or by e-mail at [email protected]. SM 6299, Rev. 2, December 2015 7-1 RAIL Team and Technical Support End of Manual 7-2 SM 6299, Rev. 2, December 2015