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1. NNO ri ar gt gt D ppp m TT 18 18 6 85 Figure 1 1 UNION SWITCH amp SIGNAL QJ ILLUSTRATIONS Typical AFO IIC Track Circuit Operation Typical AFO IIC Highway Crossing Layout With Overlapping Track Circuits AFO IIC Receiver Block Diagram AFO IIC Transmitter Block Diagram Maximum Block Length Requirements for diocking Reactor Applications of Reactor to AFO IIC Track Circuits Track Lead Lightning Protection Transmitter and Receiver Track Lead Lightning Protection Coupling Units and Connections Power Supply Lightning Protection Typical Wire Connections for Transmitter and Receiver Track Coupling Unit Internal Wiring Connections Groups 1 and 2 N451052 1901 and 1902 Track Coupling Unit Internal Wiring Connections Groups 3 and 4 451052 1903 and 1904 AFO IIC Transmitter Unit Schematic Diagram Transmitter Test Set Up Physical Locations of Transmitter Test Points Schematic Locations of Transmitter Test Points Transmitter Test Oscillograms AFO IIC Receiver Unit Schematic Diagram Receiver Test Set Up Using Matched Trans mitter and Receiver iii 5 3 4 5 5 5 6 5 7 5 8 5 11 12 5 14 4 UNION SWITCH SIGNAL Figure 5 8 Table No ILLUSTRATIONS Cont d Receiver Test Set Up Using Function Genera tor and Audio Amplifier Physical Locations of Receiver Test Points Schematic Locations of Receiver
2. D is less than 0 7 ohm Blocking Reactors may also be used for applications as shown in Views B to D Figure 2 3 View B Allows the dc track circuit to be shunted by a switch circuit controller without shunting the signal View C Defines the AFO track circuit at a specific point with insulated joints and allows the dc circuit to pass View D Keeps the AFO signal out of the fouling circuit at a turnout 2 5 TRACK LEADS AND POWER SUPPLY Leads from the AFO IIC units to the track should be arranged to minimize their series inductance Unsheathed single wires may be used in pairs provided that they are twisted 3 twists per foot or kept together within the same conduit Metal sheathed single wires should not be used Sheathed wire or conduit is not required for AFO IIC wiring within the wayside housing Transmitter and Receiver Unit of the same frequency should have its own leads to the track The battery charger rectifier leads should be wired directly to the battery and then to the power busses or equipment to prevent the battery from being removed from the circuit due to a broken wire and to ensure a ripple free power supply A resistor should never be placed in the power lead to a transmitter 4 or receiver since the total power lead resistance must be less than 0 15 ohm for transmitters and 0 5 ohm for receivers either of these values is exceeded or if a signal or rippl
3. R2 7 nns JLiLIOs4 d 89 R13 e gt Figure 2 Input Filter Component Layout Rev 6 85 6134 p A 5 UNION SWITCH amp SIGNAL ining Input Filter 451522 5302 to 5321 Frequency Determ Components A 3 3 pe 559822 65 56 8 pres 15 meme 5 Mee e Re pie IER low wise LL Fs fe Joes em fe E es bes LE o gt e bes pow pes eni Lime LER buat ewe ep 9 9 22 erio jee bed 10112289 20 oe bee se ie 9 241 1509 bzos goos 9215 eis 680262 iove ues fpes pos t y 28538287 poe 821500 Bes ojs pos c 82102421 01 Jeejee ses jose 422
4. l i i 50 H H i i 1 t i Poi tgs i H 21 1 501 i ii i i om m 1 1 12 1 1 4 1 4 ane 1 i 6u i i i anoo 1 T 1 H 1111 1 t 1 am tji x LCS i d 75 Hfi i t on 095 00981 M i 037 1111 i ii Am 4 1 9 9 1 4 d 8 H pars av 1 i Cr i a 3 i i po 3 d i fu i H fv i TO 1 H fet gt Laa tA 1535 1 17 34 3402 Wous 1 4 1 i Ld i La am o am o am a am o om o em 0 am a am 0 TT E 5 com 4 O homo ue suc m 6 mm mii ano am cum sm donem Ce aaia an i 9 vi el T 6 9 Schematic Locations of Receiver Test Points Rev 6 85 Figure 5 10 6134 p 5 18 UNION SWITCH amp SIGNAL D CONNECTION POINT 16 OSCILLOSCOPE TIME BASE INCREASED BY 10X 2 0 V DIV CONNECTION POINT 14 VERT 0 5 V DIV CONNECTION POINT 11 VERT 1 0 o gt 28 gt gt CONNECTION POINT 17 VERT 2 0
5. THE BRACKETED NOMENCLATURE IS VALID THE UNBRACKETED COMPONENTS ARE FORMANCE OF THIS IRCUIT ALL DELETED FROM F451522 45XX THESE BOARDS ARE NOT COVERED IN THIS MANUAL COMPONENTS SHALL BE REPLACED THE SECONDARY CIRCUIT OF THE OUTPUT TRANSFORMER T3 HAS ONE 1 EXTRA TAP FOR SUFFIXES 2935 THRU ONLY BY THOSE SPECIFIED ON THE 2944 AND 15 SHOWN SEPARATELY US amp S BILL OF MATERIAL 3UFFIXES 2935 THRU 0451318 0301 Rev 6 Figure 5 1 AFO IIC Transmitter Unit Schematic Diagram Rev 6 85 6134 5 3 4 UNION SWITCH amp SIGNAL QJ waveforms and voltages generated the AFO IIC transmitter Small variations in the actual waveforms and voltages may occur with the particular unit under test These are acceptable for test results NOTE The oscilloscope horizontal sweep rate settings required to produce the represented waveforms will vary depend ing on the selected frequency and code rate of the AFO II unit under test Except where noted the oscilloscope time base is the same for all waveform diagrams Battery voltage 12 1 Vdc The oscilloscope probe input imped ance is 10 megohms OSCILLOSCOPE PROBE GND TRANSMITTER OUTPUT LOAD 20 10W 190 TOL TO TRANSMITTER PCB JUNCTIONS C3 R5 AND R8 D2 WHEN SPECIFIED IN TEST DC POWER SUPPLY 12 1 VDC FREQUENCY COUNTER Figure 5 2 Transmitter Test Set Up 6134 p 5 5 D UNION SWITCH amp SIGNAL Connection Poin
6. 1 l cio 02 1 2 2N5962 04 l 03 R21 2N2210 184003 ER R24 06 T8 18 6 c9 1 aur 1 01 01UF J 2N5962 LOK D5 i 1N4003 ch 05 068UF 2N4037 IN281 R25 i 5 lt lt 470 i 3 L L3 K gt 1 C 000 74 BOARD 2 d DEMODULATOR RELAY DRIVER 2 N451522 68XX Q0 oA oom UMS 6 CMM D P 6 sui S ee 2 5 6 UEM 4 4 G WARNING THIS IS A VITAL SAFETY CIRCUIT ANY CIRCUIT CHANGE OR SUBSTITUTION COMPROMISE THE SAFE PER FORMANCE OF THIS CIRCUIT ALL COMPONENTS SHALL BE REPLACED ONLY BY THOSE SPECIFIED ON THE US amp S BILL OF MATERIAL x Figure 5 6 AFO IIC Receiver Unit Schematic Diagram Rev 6 85 6134 5 11 12 UNION SWITCH amp SIGNAL 5 level detector 22 KHz output signal of the oscillator is amplified by Q2 03 04 and Q5 The signal is then rectified and filtered by C12 C13 D6 and D7 to produce a negative dc voltage sufficient to energize the AFO relay To guard against false pickup of the track relay due to radio interference inductiv
7. Connect the frequency count is er to the junction of C3 and R5 and AAR terminal 2 dc Connect the frequency counter 2 to the junction of R8 and D2 and AAR terminal 2 NOTE UNION SWITCH amp SIGNAL D Verification Frequency should be within 13 of modulation rate Check value against Table 2 1 If modulation frequency exceeds 1 limit go to section 5 2 6 Carrier frequency should be within 0 4 of its specified frequency If carrier fre quency exceeds the 0 4 limit go to section 5 2 6 For a quick check go to step 6 and verify that the level of the output waveform is correct If not con tinue with step 3 Connect oscilloscope to Con 3 nection Point 2 shown in Fig ures 5 3 and 5 4 Connect oscilloscope to con 4 nection Point 3 shown in Fig ures 5 3 and 5 4 Connect oscilloscope to Con 5 nection Point 5 shown in Fig ures 5 3 and 5 4 Connect oscilloscope to Con 5 nection Point 7 shown in Fig ures 5 3 and 5 4 Amplitude of modulated carrier Signal should be 8 8 0 8 volts P P See Fig 5 5 os cillogram 2 for general shape and dc level of waveform P P and dc values are incor rect go to section 5 2 6 Amplitude of modulated carrier signal should be 1 55 0 2 volts P P See Fig 5 5 os cillogram 43 for general shape and dc level of waveform If P P and dc values are incor rect go to section 5 2 6 Amplitude of modulated carrier signal should be 2 8
8. Ideally frequency selection of AFO IIC units should be staggered When designing an AFO IIC system observe the following rules 1 Obtain optimum separation from the sum and difference frequencies of assigned AFO IIC frequencies 2 Avoid harmonics up to the fifth harmonic of AFO IIC frequencies 3 Minimize harmonic mixing and the mixing of harmonics with the assigned AFO IIC frequencies 4 Obtain optimum separation from the 60 cycle power frequency and its harmonics and the mixing of these with AFO IIC frequencies 2 1 2 Compatibility with Motion Monitor Table 2 2 shows the frequency compatibility between some pre selected AFO IIC and Motion Monitor frequencies Other AFO IIC frequency allocations must follow these rules 1 Avoid AFO frequencies which are a harmonic of the Motion Monitor frequency up to the seventh harmonic 2 Obtain optimum separation from the 60 cycle power frequency and its harmonics and the mixing of these with Motion Monitor frequencies and its harmonics 6134 2 1 UNION SWITCH 8 SIGNAL Table 2 1 Basic Audio Frequency Ranges Frequency AFO IIC 22 Coupling Unit Frequency Designation Frequency Range 1 2 3 4 5 6 7 8 9 Table 3 2 6134 2 2 870 885 930 945 980 1050 1120 1180 1215 1285 1330 1420 1520 1660 1860 1945 2140 2365 2540 2720 3360 3410 800 875 876 960 961 1055 1056 1155 1156 1265 1266 1385 1386 1520
9. continue with step 4 l Repeat Step 2 Same as step 2 5 4 5 Procedure Follow Up Failure of the coupling unit to meet the frequency or output level specifications can be attributed to any of the components in the unit The most likely are the capacitors coupling unit that fails the above tests should be returned to US amp S for repair and recalibration NO attempt should be made to replace components and return the unit to service 5 5 BLOCKING REACTOR The AFO Blocking Reactor is not serviceable either in the field or at the factory defective it should be replaced with a new unit 6134 p 5 25 26 SERVICE MANUAL 6134 Appendix 9 Parts List for AFO IIC Audio Frequency Overlay System and Support Equipment DECEMBER 1984 Rev June 1985 UNION SWITCH amp SIGNAL DIVISION ID0001F DN0003F AMERICAN STANDARD INC 6 85 250 2314 1 ICAN ST INC SWISSVALE 15218 USA UNION SWITCH amp SIGNAL A l UNIT PART NUMBERS 1 1 Frequency Classed Units Frequency AFO IIC AFO IIC Coupling Range Hz Transmitter Receiver Unit N451052 Carrier N451052 N451052 Groups 2 1 2 Miscellaneous Units Blocking Reactor All AFO IIC Frequencies N451036 0302 Blocking Reactor All AFO IIC Frequencies Microcode Application N451036 1701 Surge Ripple Filter 12 Vdc 2 5 amps N451036 0702 Lightning Arrester 32 Vdc 25
10. 0 18 0 15 mFd 0 10 mFd 0 082 mFd 0 056 mFd 0 039 mFd US amp S Part No J709145 0337 J709145 0139 J709145 0138 J709145 0262 J709145 0149 J709145 0073 J709145 0150 Rev 6 85 Oto RS ee O 4 1 O RY RELAY DRIVER PCB 5 UN451522 68 DEMODULATOR AND 4 UNION SWITCH amp SIGNAL D 155 REV 8 1 1 1 1 41 41 FREQUENCY HZ gem c 1 xis VI R5 Or O TP8 eu ID D D EJ qr 1 RE TO CIT RIO 1 po 17 E E 2 22 E vL M 4 E H E h 2 C 8 658 04 4L 750 LE LI ES Figure A 3 Rev 6 85 Demodulator Input Driver PCB Component Layout 6134 p A 9 Q UNION SWITCH amp SIGNAL 4 AFO IIC TRANSMITTER BASIC ASSEMBLY See Figure 4 Box Bracket Support Cover Bracket Mounting Block Terminal Holder Fuse Fuse 2 Amp Grommet Screw 10 32 x 5 8 Rd Stl Washer 10 Lk Stl Nut 10 32 Hex Stl Screw 1 4 20 x 1 2 Rd Stl Washer 1 4 Lk Stl Nut 1 4 20 Hex Stl Screw 10 32 x 1 2 Rd Stl Washer Nut 14 24 Hex Brass Terminal Nut 14 24 Hex Brass Screw 6 32 x 1 4 Rd Stl Washer 6 Shakeproof Lk Stl Wire 20 Red Wire 20 White Wire 20 Brown Wire 20 Yellow Transmitter PCB Refer to section A 4 X for part num
11. 1444 N451522 4501 J 720888 33 121754_114 106549 033 109034 3 1169056 1 33 N451030 4427 44 1451030 4454 44 451030 4447 44 REDDERE MEER 124 03 ZOSP ZZSIGTN dod 2 9 jeg Aouenbeigd 2 TWNDIS 8 H21IMS NOINn Y NN UNION SWITCH amp SIGNAL D THIS PAGE INTENTIONALLY LEFT BLANK 6134 15 by UNION SWITCH amp SIGNAL A 6 Box Bracket Cover Bracket Mounting Block Terminal Board Component Support 1 2 in Grommet Rubber Screw 10 32 x 5 8 Rd Stl Washer 10 Lk Stl Nut 10 32 Hex Stl Screw 1 4 20 x 1 2 Rd Stl Washer 1 4 Lk Stl Nut 1 4 20 Hex Stl Screw 10 32 x 1 2 Rd Stl Washer Nut 14 24 Hex Terminal Nut 14 24 Hex Brass Screw 6 32 x 3 8 Rd Stl Washer 6 Shakeproof Lk Stl Capacitors Selected at Manufacture 1 0 mFd 200 Vdc 0 5 mFd 200 Vdc 0 1 mFd 200 Vdc 0 05 400 Vdc 0 01 400 Vdc Wire 20 Red Wire 20 Orange Wire 20 Yellow Wire 20 Green Brass Refer to section 7 6134 p A 16 TRACK COUPLING UNIT BASIC ASSEMBLY See Figure A 6 US amp S Part No 451053 5101 451053 5201 451053 5602 451053 5501 181831 9751169 9052566 9047733 90
12. oscillogram 14 for general shape and dc level of wave form P P value is incor rect go to section 5 3 6 Amplitude of 22 KHz signal should be 10 4 1 0 V See Figure 5 11 oscillogram 16 for general shape and dc level of waveform P P value 15 incorrect go to section 5 3 6 The receiver relay should be energized and the dc voltage falls between 5 5 and 8 0 Vdc 5 3 6 Procedure Follow Up Failure of any step from 5 through 10 can indicate a number of circuit or component defects If the receiver does not satisfy step 6 steps 1 through 5 should be rechecked If the step 5 result does not meet the 0 03 volts P P tolerance but shows 0 25 volts P P instead return to step 3 and readjust the power amplifier output level to 3 3 millivolts RMS This is the upper allowable limit of the receiver s input level Then recheck step 6 A shift in the carrier and or modulation frequency equal to their allowable tolerances could affect the signal level in step 6 When an AFO IIC receiver fails the verification test it should be returned to US amp S for repair and recalibration This is particularly true if any of the following components are defective Demodulator Relay Driver Board Integrated circuit Capacitors Cl C2 Resistors R4 R5 Input Filter Board Inductors L1 L3 Transformers T2 4 T5 Capacitors Cl C2 C3 C4 C5 CX Resistors R3 R6 R7 R9 R10 R13 These components either direc
13. 1 LEAD 1 C C C gt lt 5 4 O lt gt OUTPUT TRACK INPUT TRACK OUTPUT LEAD 2 LEAD 2 CIRCUIT DIAGRAM FOR BOARD 2 N451053 5802 Figure 3 3 Track Coupling Unit Internal Wiring Connections Groups 3 and 4 N451052 1903 and 1904 6134 p 3 4 UNION SWITCH amp SIGNAL D After making the proper internal connections connect the unit to the track as follows see Figure 2 5 1 Connect track leads from terminals 1 and 2 to the rails on the transmitter side of the insulated joints 2 Connect track leads from terminals 3 and 4 to the rails on the receiver side of the insulated joints 3 1 4 Blocking Reactor See Figure 2 3 Asc required by the application connect the Blocking Reactor in series with one side of a circuit or track lead using terminals 1 and 2 3 2 EQUIPMENT ADJUSTMENTS NOTE Do not proceed with the following adjustments until all wiring connections have been completed Initial adjustments must be made as follows l Using a voltmeter check for correct output voltage on the dc supply that will be used at the transmitter and receiver nominal 12 volts 2 Connect dc power to all AFO IIC equipment make certain to observe proper polarity NOTE The equipment will not be damaged if dc power is applied with the wrong polarity but the protective fuses will be blown and must be replaced before further operation 3 Connect dc voltmeter minimum 10 000 ohms volt sen
14. 1521 1665 1666 1825 1826 2000 2001 2190 2191 2400 2401 2630 2631 2885 2886 3160 3161 3465 3466 3800 3801 4165 4166 4560 4561 5000 Selected Compatible Frequencies of AFO II and Motion Monitor Equipment UNION SWITCH amp SIGNAL D 2 1 3 Compatibility With Coupling Units Compatible AFO IIC and Track Coupling Unit frequencies are shown in Table 2 1 Frequencies not compatible with the AFO IIC Track Coupling Units must be applied in a track section where it is not necessary to bypass an insulated joint 2 1 4 Basic Application Rules Certain basic rules must be followed in the application of AFO IIC track circuit equipment to ensure maximum effectiveness and security These are as follows 1 not repeat the same frequency on the same track unless the track circuits are separated by two pairs of insulated joints a If a coupling unit is used to bypass a set of insulated joints these joints may not be counted in applying Rule 1 above b Frequency separation between adjacent AFO IIC pairs in the same block must be at least 25 apart 2 same AFO IIC frequency must not be located adjacent on parallel tracks 3 When more than one highway crossing is involved in an AFO layout a ripple free power supply must be provided for the transmitters Surge Ripple Filter N451036 0702 is available for insertion between the transmitter and the power supply refer to section 2 7 In selecting and applyin
15. 3 2 and 3 3 for coupling unit wiring connections NOTE Since each Track Coupling Unit has tuned internal taps for each frequency in its class one unit is required for each frequency passed around the insulated joint pair Mac Each time an AFO IIC signal is coupled around insulated joints the effective length of the AFO track circuit is reduced by an average of 200 to 300 feet depending on the location of the unit within the track circuit Due to severe restriction of effective track circuit lengths coupling units cannot be used to bypass insulated joints in the higher frequencies 2 4 BLOCKING REACTOR 2 4 1 General Application Blocking Reactors are used to block the AFO signal while passing dc and low frequency ac For example to prevent shunting the AFO Signal through the battery a Blocking Reactor must be installed in series with one lead of an existing dc battery rail connection which occurs near an AFO IIC track circuit The purpose of the reactor is to block the AFO signal while passing and low frequency ac See View A of Figure 2 3 This is not necessary if an AFO IIC track circuit occurs near the relay end of an existing dc track circuit The coils in the relay will provide the necessary impedance to block the AFO signal See Figure 2 3 for other applications ut 6134 p 2 4 Rev 6 85 4 UNION SWITCH amp SIGNAL 2 4 2 AFO and Microcode Compatibility In applications where Microcode
16. 7 lt sol _____ mw N mauu 21 15 i 211021 Sml det as 2 a En Figure 5 Transmitter Component Layout 6134 p A 13 Cn gt 1 gt PART NO OHM PART OHM PART MFO PART NO MFO PART MFO 0451030 5 0451030 SH 0451030 SH 4502 80010815 451522 4501 77121064 15 7120115 82 7106143 22 17109033 110 J103033 10 451030 4408 44 451030 4448 44 451030 4428 44 4503 816 T0360 1121064 15 7720715 82 2106143 2217109033 10 13109033 110 4403 4 44111 493 4504 961 10 1055 1121064 11 56 7120893 6 8 2106143 22 7103033 10 1 106816 18 sa 4444 4505 1056101155 3 __ 4121080 2 1120893 68 7106143 22 1106816 8 77086 44 4493 4506 1156 10 1265 11121080 2K 1720893 6 8 7105562 1 12 7106816 8 13106838 5 4au 1 4501 1066 TO 1385 11121080 12 12120758 5 6K 3 706562 1 12 1106816 8 13706838 15 443 11 asso 4031 4508 1386 10 1520 7121064 5 7720758 56 7 106562 1 12 13106816 8 17109034 13 s Jj cup M 4509 1521
17. Capacitor 15 mFd 10 20 Vdc J706891 C9 10 12 Capacitor 0 0033 mFd 2 200 J709145 0082 11 11A Capacitor Capacitor 100 mFd Tant 10 20 Vdc 706416 01 Diode Zener 1N4730A 3 9 Vdc J726150 0120 D2 4 5 Diode 144003 17723555 D3 Diode 61432 J723881 Operational Amplifier 3160 J715029 0223 IC2 Operational Amplifier 3130T J715029 0128 Ll Inductor L2 Inductor 01 3 Transistor 2N5087 J731398 0027 Q2 Transistor 2N5210 J731398 0026 04 Transistor 2N2270 J731186 Q5 Transistor 2N4037 J731291 Q6 7 Transistor MJ1000 J731427 Resistor 120 Ohms 5 2 J735519 0058 R2 Resistor 3 3K Ohms 5 1 2 J720888 R3 9 15 Resistor 10K Ohms 5 1 2 J720883 R4 5 Resistor R6 6 Resistor TBD 7 Resistor R8 Resistor 47K Ohms 5 1 2 W J720846 R10 Resistor Ohm 5 1 2 W J720882 Rll 11A Resistor TBD R12 Resistor 330K Ohms 5 1 2 W J720890 R13 Resistor 150K Ohms 5 1 2 W J720840 R14 16 Resistor 15K Ohms 5 1 2 W J720885 R17 Resistor 100 Ohms 5 1 2 W J721194 R18 Resistor 30 Ohms 5 1 2 W 723586 Tl Transformer T2 Transformer 451030 3551 T3 Transformer 451039 3801 Rev UNION SWITCH amp SIGNAL D if 6 on oe A Al ISP 19 Qe 5 1 R9 r m 7 E D VETO TM quei ode dtf od 1220 R12 cun N N UNE
18. See Figure A 2 C1 C2 C3 Frequency Determining part part numbers TBD values determined during assembly and testing Capacitor Capacitor TBD Capacitor 0 1 mfd 200 Vdc Capacitor 0 1 200 Vdc Capacitor 10 mfd 20 WVdc Diode Schottky 1N6263 Diode 1N914A Inductor Resistor 1 2K Ohms 5 1 4W Resistor TBD Resistor 5 6K Ohms 5 1 4W Varistor Disc 1 4 W 15 Vdc Resistor Resistor 270K Ohms 5 1 2 W Resistor 2 7 Megohm 5 1 2 W Resistor 820K Ohms 5 1 2 W Resistor Ohms 5 1 2 W Resistor TBD Resistor 1 Megohm 5 1 4 W Resistor TBD Resistor 13K Ohms 5 1 2 W Resistor 22K Ohms 5 1 4 W Resistor TBD Resistor 2K Ohms 5 1 2 W Transistor 2N5962 18 6134 p A 4 Capacitor 0 022 mFd 10 100 Vdc 4LD Resistor 2 7K Ohms 5 1 4 W 4 Ter 4 Ter refer to section A 3 3 for 17706844 7702280 709145 0211 706373 726150 0127 7726031 J735519 0342 J735519 0343 J735534 J720760 J735519 0074 J720776 J720838 J735519 0345 J735254 J735519 0319 J735519 0360 J721080 J731398 0040 Rev 6 85 UNION SWITCH 8 SIGNAL INPUT FILTER N451522 53 REV 8 FREQUENCY HZ _ 7 1 ax l
19. Stl 4052531 15 Washer 8 Lk Stl J047681 16 Nut 8 32 Hex Stl 7048166 17 Terminal J730039 18 Wire 18 Teflex White A045010 0004 19 Wire 418 Teflex Black A045010 0001 20 Wire 18 Teflex Red A045010 0003 21 Wire 418 Teflex Blue A045010 0005 22 Inductor Torodial 23 Capacitor Frequency determining part refer to section A 7 2 for part numbers A 7 2 Frequency Determining Components Torodial Unit No PCB No Inductor N451052 N451053 Ll L2 Capacitor N398916 001 Cl mFd 200 Vdc J701760 C2 0 mFd 200 Vdc J702617 N398916 002 0 mFd 200 Vdc 7701760 2 0 mFd 200 Vdc 7702617 438610 1 3 10 mFd 200 2709033 N438610 001 1 3 10 mFd 200 Vdc J709033 6134 p A 18 Rev 6 85
20. be traversed the frequency of an AFO IIC transmitter receiver pair on either side of the joint must be the same as the coupling unit Four coupling units are available Each is capable of passing sever al different distinct frequencies three units pass six frequencies one passes four frequencies see Figure 3 2 The units have tuned taps for each frequency in its group Thus a different unit is re quired for each frequency to be passed around the insulated joints The frequency determining taps are located inside the unit and must be connected to the proper taps as determined by the selected opera ting frequency The Track Coupling Unit has the same housing and mounting options as the AFO IIC receiver and transmitter Table 3 1 contains general part number references for the Track Coupling Units 1 6 2 Blocking Reactor The Blocking Reactor blocks the AFO signal while passing dc and low frequency ac Reactor 451036 0302 is recommended for this application It has a dc resistance of 0 01 ohm and a current rating of 7 amperes This reactor may be mounted on a relay rack in a PN 250 space or on a wall or shelf Dimensions are 8 x 5 mounting plate with a depth of 3 5 8 Refer to section 2 4 for various applications to AFO IIC track circuits WARNING AFO EQUIPMENT IS DESIGNED TO OPERATE OVER A NORM ALLY EXPECTED VARIETY OF ENVIRONMENTAL CONDITIONS HOWEVER ELECTRIC PROPULSION EQUIPMENT EMPLOYING PHASE CONTROL OR CHOPPER CONTROL MAY
21. between the track leads to each unit and series arresters from each track lead to a common ground bus bus should be connected directly to the housing signal poles and all grounds at the location to limit the surge voltage between any connections on the equipment or between the equipment and the housing NOTE Ground wires should be short and without sharp bends Each of the series arresters should limit the surge voltage across itself to less than 1500 volts peak to prevent the between any two points from exceeding 3000 volts peak 2 6 2 Track Terminal Protection Lightning damage can occur from surges entering the AFO IIC units either through the track terminals or through the battery terminals These terminals must be protected as follows The track terminals of each AFO IIC Transmitter and Receiver should be protected by both series and shunt lightning arresters as shown in Figure 2 4 and the coupling unit as shown in Figure 2 5 Reference 1 in these figures should be a US amp S USGA Arrester with a minimum breakdown rating of 500 peak volts and a maximum rating of 1300 peak volts Reference 2 should be a US amp S USGA Arrester with a minimum breakdown rating of 75 peak volts and a maximum rating of 200 peak volts Ground connections reference 3 should be made to the common low voltage ground bus system that includes grounds at cases or houses Make ground connections and jumpers with 46 AWG wire Messenger
22. frequency A negative dc voltage is developed from the rectified output to power a high frequency oscillator which acts as a level detector The output of the oscillator is amplified and again rectified to develop a negative dc voltage to drive the relay Also included on the Demodulator Relay Driver board is power surge protection circuitry at the battery connection to protect the solid State electronics against voltage spikes Reversed battery protection is also included 1 3 4 Specifications Input Voltage 9 5 16 2 Vdc Input Current 0 07 amp at 12 Vdc Output Voltage 5 05 Vdc minimum with 3 mV RMS 400 ohm load input signal and 9 5 volts battery Signal Sensitivity 3 0 0 3 millivolts RMS minimum detectable signal 14 1 2 0 millivolts P P during the period of the modulation cycle when the signal is at a maximum Input Impedance Track 1 25 ohm at center of assigned frequency nominal Output Load 400 or 500 ohm Relay Bandwidth 3 db at 4 0 of assigned frequency Operating Frequencies Refer to Table 3 1 Temperature Range 409 to 719 409F to 1609 Surge Protection Built in Dielectric Breakdown Test 3000 Vdc rms at 60 Hz between track leads and input battery leads 1 4 RECEIVER RELAY A 400 or 500 ohm biased dc relay is typically used as a receiver relay for the AFO IIC system Refer to section 2 2 for recommended relays and application data 6 85 6134 p 1 5 UNION
23. is used the overlap distance will be increased proportionately The following adjustment should be made when the ballast is in good condition 20 ohms or higher per one thousand feet This should avoid any appreciable decrease in shunting sensitivity with any further improvement in ballast Also all batteries must be fully charged and all track equipment connected when the adjustment is made 6 Loosen the receiver sensitivity adjustment lock nut and adjust the receiver sensitivity so that the relay just drops out with the shunt in place Observe and record the voltmeter reading 7 Tighten the sensitivity adjustment lock nut and check the voltmeter to see that such tightening has not changed the voltmeter reading necessary loosen the nut readjust the sensitivity and tighten the nut again 8 Remove the track shunt The relay should then pick up 9 Observe and record the voltmeter reading 10 Check that the circuit shunts with a 0 06 ohm shunt at the transmitter end of the circuit NOTES If a transmitter or receiver is ever removed re placed in service the circuit must be readjusted according to the above procedure 6134 3 6 UNION SWITCH SIGNAL D Multiple receivers are frequently used provide several track circuits with one transmitter shunting of each receiver must be adjusted individ ually Adjustment of one receiver will not appreci ably affect the adjustment of another re
24. ripple filter must be used more than one filter is required because of current capacity all transmitters should be connected to one filter and all receivers to another filter A transmitter and receiver of the same frequency should not be connected to the same surge ripple filter nor should they be connected to the same battery unless a surge ripple filter is employed to isolate their power leads This requirement is satisfied by placing a surge ripple filter in the power leads to either unit but preferably the receiver When more than one transmitter receiver pair is powered from the same source connecting all the receivers to one filter up to the filter s current capacity will satisfy the requirement Refer to Table 6 1 for Surge Ripple Filter part number 6134 p 2 11 12 22221222 UNION SWITCH amp SIGNAL D SECTION III INSTALLATION AND ADJUSTMENTS NOTE All equipment must be installed in accordance with approved application plans CAUTION LEAVE DC POWER FOR ALL AFO IIC EQUIPMENT DISCONNECTED UNTIL INITIAL EQUIPMENT ADJUSTMENTS ARE COMPLETE section 3 2 OTHERWISE EQUIPMENT DAMAGE MAY RESULT 3 1 WIRING CONNECTIONS 3 1 1 AFO IIC Transmitter See Figure 3 1 l Connect the positive and negative power supply to terminals 1 and 2 respectively Make certain to observe correct polarity 1 dc 2 2 Connect the track leads to terminals 3 4 3 1 2
25. series tuned filter comprised of Cl and 11 Along with the above components C2 C3 C4 T2 L3 and T4 make up a narrow band pass filter The filter passes the ampli fied carrier with its modulation side bands but rejects noise and adjacent channel signals The output of the filter is terminated by network Rl R2 and 84 which imposes within limits a constant load to the filter R2 provides a level adjustment to compensate for var iations from filter to filter Step up transformer T5 sufficiently increases the signal level to enable detector Dl to operate in its linear region at low temperatures Network R3 R13 is used for fac tory adjustment of the receiver for minimum sensitivity The 8 R9 R10 C7 and C8 circuit shifts the dc operating level to about half the battery supply voltage 01 and Q2 make up emitter follower circuit which transforms the impedance to suffi amp ient output level To prevent potential electrical interference which could result in energizing the relay the Darlington s circuit 01 and Q2 acts as a signal limiter circuit whose output is limited to approximately 1 5 Vpp Extraneous electrical impulses are limited to the 1 5 Vpp therefore having no effect on the demodulator circuit on the Demodulator Relay Driver board Demodulator Relay Driver Board 451522 68 The output of the Input Filter board is resistively coupled to the active band pass filter consisting of and associated cir
26. shown in Figures 5 9 for general shape dc of wave and 5 10 TP5 on board 1 form If P P value is incor rect go to section 5 3 6 Amplitude of signal should be Connect a high impedance in put probe of the oscillosope 0 29 03 V P P Figure to oscilloscope Connection 5 11 oscillogram 11 for gen Point 11 shown in Figures 5 9 eral shape nd dc level of and 5 10 turret lug E waveform P P value is incorrect go to section 5 3 6 NOTE DC voltages of all the measured ac signals must fall within 103 of those levels shown in the test point oscillogram in question unless otherwise noted 7 Connect oscilloscope to Con 7 Amplitude of signal should be nection Point 12 shown in Fig 4 9 07 V P P See Figure ures 5 9 and 5 10 4 5 11 oscillogram 412 for gen board 2 eral shape and dc level of waveform If P P value is incorrect go to section 5 3 6 6134 p 5 21 4 UNION SWITCH amp SIGNAL OPeration Connect oscilloscope to 8 nection Point 14 shown in Fig ures 5 9 and 5 10 2 Connect oscilloscope 9 nection Point 16 shown 14 ures 5 9 and 5 10 EET on board 2 Connect a dc voltmeter across 110 terminals 6 R and 5 R see Figure 5 10 Verification Average amplitude of 22 Khz signal should be 0 55 0 1 V P P DC level should be 2 0 0 3 Vdc See Figure 5 11
27. wire or metallic sheath of cable if used may serve as tie in between cases or houses 2 6 3 Battery Line Protection Although the AFO IIC Transmitter and Receiver have built in surge suppression they require additional protection across the power supply This is accomplished by using the USG Shunt Arrester reference 2 of Figure 2 6 across the power leads to the AFO IIC equipment 6134 p 2 9 Y UNION SWITCH 8 SIGNAL TRANSMITTER N451552 0302 USG A ARRESTER WITH TERM BLOCK N451552 0101 USG A ARRESTER 3 GROUND BUS TWIST PAIR Figure 2 4 Track Lead Lightning Protection Transmitter and Receiver lt TO TRANSMITTER E C LH TO RECEIVER 2 3 COUPLING UNIT 3 N451552 0302 USG A ARRESTER WITH TERM BLOCK 2 15520101 USG A ARRESTER 3 GROUND Bus TWIST PAIR Figure 2 5 Track Lead Lightning Protection Coupling Units and Connections BUS 2 UNITS 2 451552 0301 USG A SHUNT ARRESTER WITH TERM BLOCK Figure 2 6 Power Supply Lightning Protection 6154 p 2 10 UNION SWITCH amp SIGNAL QJ 2 7 SURGE RIPPLE FILTERS Normal operation of AFO IIC Transmitters and Receivers directly from a rectifier is not recommended since reliability of filter components will decrease due to excessive ripple If the battery supply has a ripple or an ac signal greater than 0 5V peak to peak a surge
28. 0 01 mFd 5 100 Vdc 706589 Capacitor 0 068 mFd 5 100 Vdc 706569 Capacitor 1 mFd 10 35 706387 Capacitor 0 01 mFd 500 V J706647 Capacitor 0 005 mFd 400 V J709145 0011 Diode 1 4003 J723555 Diode Zener 1 748 3 9 Vdc 5 J726150 0071 Diode 1 281 J723881 Operational Amplifier LM224J J715029 0262 Inductor 10 000 micro H J703315 Inductor J709602 Transistor 2N5962 18 J731398 0040 Transistor PN3644 5 J731283 Transistor 2N2270 J731186 Transistor 2 4037 J731291 Resistor 38 3K Ohms 1 1 4 W J735519 0350 Resistor TBD Resistor 20K Ohms 1 1 4 W Resistor 1 Megohm 5 1 2 W J735519 0351 J735519 0345 Resistor 39K Ohms 5 1 2 W J720765 Resistor 4 42K Ohms 1 1 2 W J735519 0173 Resistor 20 Ohms 5 1 2 W J072276 Resistor Ohms 52 1 2 W J720882 Resistor 100 Ohms 5 1 2 7720838 Resistor 10K Ohms 5 1 2 1720883 Resistor 470 Ohms 5 1 2 9721065 Resistor 2 2 Megohm 5 1 2 W J720845 Resistor 1 Megohm 5 1 2W J720839 Frequency Determining part refer to section A 3 5 for part numbers TBD Values determined during assembly and testing Rev 6 85 6134 7 4 UNION SWITCH amp SIGNAL 3 5 Demodulator Relay Driver 451522 6802 to 6808 Frequency Determining Components PCB Basic 6801 6134 p A 8 Modulation Frequency Hz Capacitors Cl C2 Description 0 22 mFd
29. 0 3 volts P P See Fig 5 5 os cillogram 45 for general shape and dc level of waveform P P and dc values are incor rect refer to section 5 2 6 Amplitude of modulated carrier signal should be 5 0 0 4 volts P P See Fig 5 5 os cillogram 7 for general shape and dc level of waveform If P P and dc values are incor rect refer to section 5 2 6 6134 p 5 9 4 UNION SWITCH amp SIGNAL 5 2 6 Follow Up failure of any step the above procedure be caused by 1 ety of circuit or component defects Failure to meet the frequency tolerance requirement in steps 1 and 2 may be due to a long term drift of associated components in the respective oscillator circuits When an AFO IIC transmitter fails the verification test it should be returned to US amp S for repair and recalibration This is particularly true if any of the following components are defective Inductors L1 L2 Integrated Circuit ICl Transformer Tl zener Diode D1 Capacitors Cl C2 C3 C4 C5 Resistors R2 R3 R4 R5 R6 R6A Cll R7 R8 R9 11 Transistor Ql R11A R17 These components either directly or indirectly affect the tuning of the carrier and modulation oscillators and gain adjustment 5 3 RECEIVER UNIT N451052 31XX TEST PROCEDURES 5 3 1 Detailed Circuit Descriptions See Figure 5 6 Input Filter Board N451522 53XX The track signal is applied to this board through a low impedance
30. 1522 68XX Refer to section A 3 2 for part numbers Refer to section A 3 4 for part numbers 6134 p A 2 Rev 6 85 UNION SWITCH amp SIGNAL D 1 1 d 1 t 1 1 1 1 3 WABCO M Iase dca z CA poe 13218 mies apm SER PART 160 4945 052 Kean yrs SENSITIVITY OFF INCREASE 25 33 Fuse _ R BATTERY 2 2 Boaro 2 J NPuT 2 8 gyi mu gt BOARD 6 a LESEND VIEW WIRING DIAGRAM Paw Sot COMPONENT SWE RECEIVER QAAR TERMINAL Figure 1 AFO IIC Receiver Basic Assembly and Chassis Wiring 6134 p A 3 D UNION SWITCH amp SIGNAL A 3 RECEIVER PRINTED CIRCUIT BOARDS 3 1 Standard Vs Frequency Determining Components The parts listed in this section are divided into Standard and Frequency Determining cateogories same operating values for all boards frequencies Frequency Determining components have variable Standard components have the regardless of the selected operating values to define the frequency and modulation rate of the board These are listed according to the defined frequency and basic part number for the board A 3 2 Input Filter N451522 5302 to 5321 Standard Components
31. 2 1 Detailed Circuit Description See Figure 5 1 The carrier frequency is determined by Tl and Cl typically adjustable via Tl over an approximate 20 variation in frequency RA in conjunction with the turns ratio in Tl is chosen for an approximate 110 feedback a compromise between failure to oscillate and continued oscillation should 1 fail to open The modulation frequency is fixed at one of six chosen rates and chiefly comprises ICl acting as a Twin Tee oscillator The 8 volt P P output is controlled by the Zener voltage of Dl approximately 4 Vdc This is intended to assure operation of Dl by incorporating it into the tank circuit of the carrier oscillator Transistor Q2 acts as a collector modulated mixer The combined signal is buffered through Q3 and passes through 11 to have the low frequency components filtered out by C5 11 and C5 are tuned to the carrier frequency and adjustable via 11 over a an approximate 20 frequency range 11 is the gain adjusting resistor signal passing through C6 now appears as a conventional 100 amplitude modulated signal IC2 is used primarily a buffer stage into transistors Q4 and Q5 and receives feedback from their common emitter output The feedback from the output allows the stage to operate class C improving efficiency 8 couples the signal into T2 which is used as a driver transformer to Q6 and Q7 the output transistors Both Q6 and Q7 act as emitter followers to drive T3 the o
32. 22 0 9 poer 8 vos 18 55362260 96 24 0 poer effec 29 e 3 954 seizes soseo b 4 f 220 1 fos t 9 ofiso t poss 9 pze 894 9 6012 66 8480 58160 05 0 0 594 is izis ocarsen o1 980 58 5021 16 ai pew on isvd 77 ON oN 5 000 66 94016903 ns 05016 0 mola iem yw GD WOME ve 239011294 Y2 62 mono v vO BAIT 433 49199901 ADOI 2 259 209 1069 09709 9NISA 3315 2 34 22 83 NOLINONI 21 12 WOLI IVar Rev 6 85 P A 6 6134 4 UNION SWITCH amp SIGNAL 3 4 Demodulator Relay Driver N451522 6802 to 6808 Standard Components See Figure A 3 Capacitor Capacitor 47 mFd 10 20 Vdc J706254 Capacitor 100 mFd 10 20 Vdc J706416 Capacitor
33. 48172 9052642 9047775 9480265 9052565 9047818 7480300 2730044 7480301 7525031 7047713 34701760 7701073 2706181 9701573 9701572 045219 0002 045219 0004 045219 0007 045219 0005 Rev 6 85 UNION SWITCH amp SIGNAL D 15 F451052 19 Rev P uud Eod Seer H E 3 a i MS 5 Gu 2 2 fi x iq Situ vw 4 15 G E 1 5 4 z lt a 9 lt eu 52 1 50 9 zH 12 D 6d lt OUTPUT H OUPLING UNIT LEAD 1 TRACK INPUT INPUT LEAD 2 TRACK InPUT 3 d T 1 is 4 E i 3 i 0 5 19 2 17 6134 Assembly and Chassis t Basic Main 1 Track Coupling Un Figure A 6 Rev 6 85 4 D UNION SWITCH amp SIGNAL 7 TRACK COUPLING UNIT COMPONENT BOARD 451053 580 See Figure A 7 A 7 1 Standard Components 1 Turret Lug M377206 Washer Felt 162571 3 Washer Insulated 328033 4 Screw 10 32 x 3 1 2 Rd Stl J052637 5 Washer 10 Flt Stl J457077 6 Washer 10 Lk Stl J047733 7 Nut 10 32 Hex Stl J048172 8 Strip terminal J724317 9 Screw 6 32 x 1 Rd Stl J525097 10 Washer 6 Flt Stl J047996 11 Washer 6 Lk 541 7047662 12 Nut 6 32 Hex Stl 7048148 13 Transformer 451039 1202 14 Screw 8 32 x 1 2 Rd
34. CREATE AN EX CESSIVE AMOUNT OF ELECTROMAGNETIC INTERFERENCE IN THE AUDIO SPECTRUM THUS CAUSING IMPROPER AND PO TENTIALLY UNSAFE OPERATION OF THE RECEIVERS SIMILARLY THE OPERATION OF HAND HELD RADIO TRANS MITTERS IN THE VICINITY OF OPEN WAYSIDE HOUSINGS MAY CAUSE SUFFICIENT RADIO INTERFERENCE TO RESULT IN POTENTIALLY UNSAFE OPERATION OF AFO AND OTHER ELECTRONIC DETECTION EQUIPMENT Proper application of AFO equipment under the conditions described above requires special engineering analysis Contact the US amp S District Sales 452444045 to discuss possible audio frequency interference of the AFO equiupment in the customer s application 6134 p 1 8 UNION SWITCH amp SIGNAL SECTION II APPLICATION 2 1 FREQENCY SELECTION 2 1 1 General The AFO IIC System provides transmitter and receiver units with all frequencies between 800 and 5000 Hz The frequency spectrum is divided into 20 groups as shown in Table 2 1 desired frequencies of the transmitter and receiver units are selected in accordance with unit part numbers Refer to section 1 1 for these part numbers WARNING THERE MUST BE At LEAST A 25 SEPARATION BETWEEN THE ASSIGNED FREQUENCIES OF ANY EQUIPMENT CONNECTED TO THE TRACK WITHIN A COMMON BLOCK BETWEEN INSULATED JOINTS IN A TWO TRACK SYSTEM THE FREQUENCY SEPAR ATION OF TRACK 1 AND TRACK 2 UNITS MUST NOT BE LESS THAN 5 OTHERWISE A HAZARD MAY BE CREATED THAT COULD LEAD TO UNSAFE OPERATION
35. PPLY Figure 5 7 Receiver Test Set Up Using Matched Transmitter and Receiver 6134 p 5 14 Q UNION SWITCH amp SIGNAL diodes D3 and 04 refer to section 5 2 1 for transmitter circuit description a result the transmitter output signal is overmodulated by an amount that can vary from one unit to the next and depends on the forward characteristics of the two diodes in question some cases therefore the transmitter would require more signal level during the on part of the period in order to provide the receiver with the same energy level This Go No Go method of testing of the receiver can result in its sensitivity having a relatively wide range of 2 7 and 4 3 millivolts RMS as measured with a true RMS voltmeter The ohm potentiometer in this set up must be adjusted so that the signal at scope test point 11 see page 5 19 20 is at 0 29 0 03 volts P P To accomplish this change the oscilloscope s vertical deflection adjustment to 0 1 V div ac The receiver input level at this point in time should not exceed 4 3 millivolts RMS as measured with a true RMS voltmeter Figure 5 8 shows the receiver unit test set up with a function generator and audio power amplifier 7 5 and 1 3 ohm resistors must be non inductive The carrier and modulation frequencies developed on the function generator must be set according to those of the receiver under test The index of modulation must be 95 or better as meas
36. REACTOR 4 1 General Applications 4 2 AFO and Microcode Compatibility 5 TRACK LEADS AND POWER SUPPLY 6 LIGHTNING PROTECTION 6 1 General 6 2 Track Terminal Protection 6 3 Battery Line Protection 7 SURGE RIPPLE FILTERS TALLATION AND ADJUSTMENTS WIRING CONNECTIONS 1 AFO IIC Transmitter 2 AFO IIC Receiver 3 Track Coupling Units 4 Blocking Reactor EQUIPMENT ADJUSTMENTS ELD MAINTENANCE 1 GENERAL 2 REQUIRED TEST EQUIPMENT 3 INSPECTION AND INITIAL CHECKS 4 MAINTENANCE PROCEDURES 4 1 Equipment Substitution Method 4 2 Voltage Measurement Method 6 85 i UNION SWITCH amp SIGNAL D iit PRP REP EPP Pee 54 d 4 d d QJ QJ I2 i B i2 S PREP lt d d EO ES ERO ES EX EO EO EO EO 89 RSS BO 3 1 I XO XO xo OY iS gt D ED S WWWW WWW 111141 OOH Pe ee de 111411 PPE l UNION SWITCH amp SIGNAL CONTENTS Cont d Section V HOP MAINTENANCE GENERAL TRANSMITTER UNIT N451052 29XX Detailed Circuit Description Required Test Equipment Test Set Up Procedure Comments Procedure Steps Procedure Follow Up RECEIVER UNIT N451052 31XX TEST PROCEDURES Detailed Circuit Descriptions Required Test Equipment Test Set Ups Procedure Comments Procedure Steps Procedure Follow Up TRACK COUPLING UNIT Required Test Equipment Test Set Up Test Procedure Comments Test Procedure Procedu
37. Receiver See Figure 3 1 1 Connect the positive and negative power supply to terminals 1 and 2 respectively Make certain to observe correct polarity dc 1 dc 2 2 Connect the track leads to terminals 3 and 44 3 Connect the and relay leads to receiver terminals 5 and 6 respectively Make certain to observe correct polarity 3 1 3 Track Coupling Units See Figures 2 5 3 2 and 3 3 The Track Coupling Unit selection groups 1 2 3 and 4 refer to Table 3 1 is based on the class of the frequency for which it is used Total track lead resistance should be kept below 0 15 ohm per pair coupling units should not be used within 100 feet of receiver or transmitter One unit is required for each frequency to be passed around the insulated joints Before connecting a coupling unit to the track set the proper as frequency as follows 1 Remove the unit from the sheet metal cover and locate the four wires on terminal strips within the cover The connections of these wires are used to set up desired frequency See Table 3 1 and Figures 3 2 and 3 3 6134 p 3 1 4 UNION SWITCH amp SIGNAL Me TRANSMITTER RECEIVER Figure 3 1 Typical Wire Connections for Transmitter and Receiver 2 Connect the black and brown wires to one of the assigned frequencies as indicated on terminals one to eight 3 Connect the white and blue wires only when one of the first three frequencies in each g
38. SWITCH amp SIGNAL 1 5 TRANSMITTER N451052 29XX 1 5 1 General The AFO IIC Transmitter has a fixed output It operates on a dc battery voltage range of 9 5 to 16 2 volts The modulated signal is designed to provide noise immunity for the circuit and reduce battery consumption by the transmitter The AFO IIC Transmitter contains one printed circuit board Transmitter 1 5 2 Transmitter Board N451522 45XX See Figure 1 4 The Transmitter board accomplishes four functions including generation of the basic carrier frequency generation of the modulation rate frequency summing of the carrier and modulation signals and voltage amplification The fundamental carrier signal is generated at the carrier oscillator and is coupled to a summing circuit A modulation oscillator generates the modulating signal It is coupled to the summing circuit where it causes the carrier signal to increase and decrease in amplitude at the modulation rate The signal after being coupled through a buffer stage is of very low energy level and requires several stages of current and voltage amplification The final stage of amplification transforms the high impedance output of the emitter follower and provides low impedance coupling to the track through a two transistor push pull power amplifier The amplifier has at its output a series resonant circuit The series resonant circuit allows easy passage of the modulated carrier frequency signal and in
39. TO 165 721064 1 5 3120168 5 6K J 106562 12 106838 5 17106817 14 sas o _ 4510 1666 TO 1825 1121080 2K 12120154 9 J 106549 0330 106838 5 12106811 14 e 11 _ 4511 182610 2000 1110080 2 14120154 9 7 106549 103313 106817 4 17709034 13 san 449 11 em 4512 2001102190 ___ 721080 12 13120144 39K J 106549 1 033 9106838 15 ms 4454 4439 4513 219110 2400 1120888 33K J 720888 133K J 1065493 033 J 106817 4 13109034 13 4 4031 4514 2401T0 2630 11120888 3 3K 5 720888 33K J 105549 103317 106838 5 1 1 4411 4l 4515 263110 2885 1120888 33 71720888 33 108549 0337 108838 15 L oes 4411 4516 258610 360 720888 33K JT21255 124K J 705549 033 7106838 15 1 44111 4511 3161 3465 1120888 133 121255 24 5 106549 033 7 7106817 14 4623 445 1 _ 4518 3466 To 3800 1120888 33 7171255 2 4 7 106549 033 J 709034 13 1109056 33 4424 1 45 u 4519 3801 10 4160 11120888 33k J721254 1 7705549 033 106838 15 4425 4520 4164110 4560 7170588 33K J121254 1 4 7105549 033 106838 5 sza t 444
40. Test Points Receiver Test Oscillograms Track Coupling Unit Test Set Up AFO IIC Receiver Basic Assembly and Chassis Wiring Input Filter Component Layout Demodulator Input Driver PCB Component Layout AFO IIC Transmitter Basic Assembly and Chassis Wiring Transmitter PCB Component Layout Track Coupling Unit Basic Main Assembly and Chassis Wiring Track Coupling Unit Component Board Assembly TABLES Basic Audio Frequency Ranges Selected Compatible Frequencies of AFO II and Motion Monitor Equipment Coupling Unit Internal Terminal Board Connections iv 5 18 5 19 20 5 24 3 5 9 11 13 17 19 6 85 UNION SWITCH amp SIGNAL 9 SECTION 1 GENERAL INFORMATION 1 1 PURPOSE This manual describes the principles of Audio Frequency Overlay AFO IIC track circuits and provides application information for the AFO IIC equipment This information is essential for planning AFO IIC installations It includes track circuit data necessary for laying out track circuits and frequency allocation rules which are necessary to provide optimum efficiency of operation 1 2 DESCRIPTION 1 2 1 General The AFO IIC is designed to provide train detection in territories without insulated rail joints so long as certain warnings and application rules are observed These are described in Sections I and II of this manual AFO IIC can be used for highway crossing application or for cont
41. UNION SWITCH 8 SIGNAL 645 Russell Street Service Manual 61 34 Batesburg SC 29006 Operation Installation and Maintenance AFO IIC Audio Frequency Overlay System Transmitter N451052 29XX Receiver N451052 31XX Track Coupling Unit N451052 190X June 1985 An ANSALDO Signal Company 1981 1984 1985 Union Switch amp Signal Inc Printed in USA Revision Index This service manual supersedes all previously issued manuals Please destroy all outdated manuals Revision 04 81 Revision 12 84 Revision 06 85 5 6134 06 85 I II III IV CONTENTS ion GENERAL INFORMATION 1 1 PURPOSE DESCRIPTION General WHE Track Circuit Operation Circuit Protection AFO IIC RECEIVER N451052 31XX General Input Filter Board N451522 53XX Demodulator Relay Driver Board N451522 68XX Specifications RECEIVER RELAY AFO IIC TRANSMITTER 451052 29 General Transmitter Board N451522 45XX Specifications AUXILIARY EQUIPMENT Track Coupling Units N451052 19XX Blocking Reactor PEP RPP Pee ww Ww N OY OY 4 C Ww N e gt N e PLICATION l FREQENCY SELECTION Ds General 1 2 Compatibility with Motion Monitor 1 3 Compatibility With Coupling Units 1 4 Basic Application Rules 2 RECEIVER RELAY 3 TRACK COUPLING UNITS 4 BLOCKING
42. V DIV CONNECTION POINT 15 VERT 0 5 CONNECTION POINT 12 VERT 2 0 VIDIV ul zi 99 2 2 2 16 2 0 VIDIV CONNECTION POINT 13 VERT 0 5 ox 82 gt 28 gt gt Receiver Test Oscillograms Figure 5 11 5 19 20 6134 p UNION SWITCH SIGNAL 9 5 3 5 Steps OPeration Verification 1 Loosen the receiver sensitiv 1 ohmmeter reading between ity adjustment lock nut and the black and orange wires of adjust the potentiometer for the sensitivity potentiometer maximum sensitivity R2 should be 0 ohms 2 Set the carrier function gen 2 erator for continuous output at the assigned carrier fre quency 0 2 and adjust the power amplifier output level to 3 0 millivolts RMS Turn on the amplitude modula tion adjust to the assigned modulation frequency 0 53 and adjust amplifier output level to 3 0 0 3 mV RMS 4 Connect oscilloscope across 4 The scope should show the the receiver input terminals index of modulation adjusted 3 and 44 to at least 95 or better but not exceeding 100 Connect a high impedance in Amplitude of signal should be put probe of the oscillosope 0 26 V P P or higher See to oscilloscope Connection Figure 5 11 oscillogram 9 Point 9
43. Vac 451552 0101 Lightning Arrester 250 Vdc 175 Vac N451552 0201 Lightning Arrester 32 Vdc 25 Vac W Term Block X451552 0301 Lightning Arrester 250 Vdc 175 Vac W Term Block X451552 0302 Rev 6 85 6134 p A 1 4 UNION SWITCH amp SIGNAL 2 AFO IIC RECEIVER BASIC ASSEMBLY See Figure 1 l Box R451053 5101 Bracket Support E R451053 5201 3 Cover M451053 6001 4 Bracket Mounting M451053 5501 5 Block Terminal M181830 6 Holder Fuse 071889 7 5 1 8 071075 8 Grommet J751173 9 Screw 10 32 x 5 8 Stl J052566 10 Washer 10 Lk Stl J047733 11 Nut 10 32 Hex Stl J048172 12 Potentiometer 100K Ohm 1 4 W R2 J620850 0057 13 Screw 1 4 20 x 1 2 Stl J052642 14 Washer 1 4 Lk Stl J047775 15 Nut 1 4 20 Hex Stl J480265 16 Screw 10 32 x 1 2 Rd Stl J052565 i 17 Washer J047818 18 Nut 14 24 Hex Brass J480300 19 Terminal J730044 20 Nut 14 24 Hex Brass J480301 21 Screw 6 32 x 1 4 Rd Stl 525055 22 Washer 6 Shakeproof Lk Stl J047713 23 Washer 3 8 Lk Int Tooth Steel J475210 25 Wire 420 Red 045219 0002 26 Wire 20 White gt 045219 0003 27 Wire 20 Orange A045219 0004 28 Wire 20 Blue A045219 0006 29 Wire 20 Yellow A045219 0007 30 Wire 20 Brown A045219 0009 31 Wire 420 Black A045219 0001 32 Wire 20 Green A045219 0005 33 Wire 20 Violet 045219 0010 34 Input Filter 451522 53 35 Demodulator Input Driver N45
44. bers 6134 p A 10 R451053 5101 R451053 5201 M451053 5603 181831 7071889 9710026 9751169 9052566 9047733 9048172 9052642 9047775 7480265 9052565 9047818 7480300 9730044 9480301 17525055 7047713 M451053 5501 A045219 0002 045219 0003 045219 0009 045219 0007 Rev 6 85 UNION SWITCH SIGNAL QJ F451052 28 Rev 2 M un IN ovum Serie o v3 e map o 12 3 4 27 e b 15 10 LEGEND TWISTED PAIR AAR TERMINAL 4 0 BATTERY PCB AOU TRACK 1 TRANSMITTER 09 OUTPUT TRACK 2 BATTERY WIRING DIAGRAM TRANSMITTER Figure 4 AFO IIC Transmitter Basic Assembly and Chassis Wiring 6134 p 11 4 UNION SWITCH amp SIGNAL A 5 TRANSMITTER PRINTED CIRCUIT BOARD NOTE Refer to section A 3 1 for description of Standard VS Frequency Determining components Frequency Determining part part numbers 6134 p A 12 refer to section A 5 2 for A 5 1 Transmitter PCB 451522 4502 to 4521 Standard Components See Figure A 5 Cl 5 Capacitor C2 3 Capacitor 0 1 mFd 5 200 Vdc J706827 4 Capacitor 0 22 mFd 5 200 Vdc J709144 0091 C6 Capacitor 0 82 mFd 10 50 Vdc J709145 0328 C7 Capacitor 82 5 300 Vdc J706939 C8 13
45. ceiver 10 After completing all adjustments a check should be made throughout the AFO track circuit end to end to insure that the track relay will shunt down with a 0 06 ohm shunt anywhere within the limits of the track circuit between the transmitter and all receivers 6134 p 3 7 8 ors UNION SWITCH amp SIGNAL 5 FIELD MAINTENANCE 4 1 GENERAL Repairs to AFO IIC transmitters receivers and related equipment should not be attempted in the field defective unit should be replaced with a properly working spare and then repaired Defective units may be returned to US amp S for repair or replacement A Returned Material Report RMR form may be obtained through any district sales office Faulty units may be isolated either through direct substitution with spare units or by taking input and output voltage measurements on the installed units Substitution of complete units is recommended NOTE If an AFO IIC Transmitter Receiver or Receiver relay must be replaced the associated track circuit must be readjusted as described in section 3 2 4 2 REQUIRED TEST EQUIPMENT A dc voltmeter is required for all types of AFO IIC field maintenance The voltmeter is used to check battery supply voltage When a spare transmitter and receivers of the proper frequency are carried to the installation no other test equipment is required When spares are not available a multimeter is required
46. cuitry filter amplifies the modulation frequency but rejects noise and adjacent channel signals C5 C6 D2 and D3 produce a negative dc from the output signal to operate a low power oscillator which acts as a 6134 p 5 10 6 85 a m o m i ea m ON FRONT SENSITIVITY Ri6 2 7K 146263 e 2 z 5 5 3 E 2 C6 D2 022UF RI3 INSI4A R6 IM 9 4 13 BOARD INPUT FILTER N451522 53XX QE 9 6 9 UND EL TE TE EL D D Wes 9 Um 6 900 6 UM uns 9 Gum Gum 8 wet iem c c Gm 5 um 9 Cum 4 xa Gam D 4 9 mm 4 WO D451318 1101 Rev 8 UNION SWITCH SIGNAL VJ cc IUE IST SIUE IUE i 1 5 1 i TP T Ri4 L5 3 B 009 1 8 2 20 lt gt j Fuse i Ri2 1 4 42K 144003 i UH 1 1 000 gt 1 6 9 LS 1 i 5 i ME 01 MFD 152 442 1 ZOV 209 ATER C5 lis ATUF R22 1
47. de distant requirement is really critical two No 2 blocking reactors may be paralleled when microcode is located at least feet from the adjacent unit 2 AREA WHERE BLOCKING REACTOR 15 REQUIRED jep MICROCODE Diagram a Microcode Application Rev 6 85 6134 2 4 4 UNION SWITCH amp SIGNAL Blocking Reactor No 1 N451036 0302 inductance of 1 9 mh and has a DC resistance of 0 01 ohm 222 Blocking Reactor No 2 N451036 1701 inductance of 1 0 mh and has a DC resistance of 0 01 ohm 6134 2 4 Rev 6 85 Q UNION SWITCH amp SIGNAL MAXIMUM C LENGTH TO OBTAIN 3 MV AT THE RECEIVER WITH 06 OHM SHUNT AND VARIOUS BALLAST CON DITIONS IN OHMS PER 1000 N fr ui gt o z u 2 lt TRACK CIRCUIT LENGTH IN THOUSAND FEET Figure 2 1 Maximum Block Length 6134 p 2 5 UNION SWITCH amp SIGNAL The need for the reactor depends upon the impedance presented by the existing dc equipment their leads their distance from the AFO IIC track circuit and the AFO IIC frequency employed One reactor is effective for all AFO frequencies Figure 2 2 shows the relationship between minimum impedance AFO IIC frequency and distance For example if the AFO frequency is 1330 Hz and the distance is 200 feet a reactor must be installed if the impedance in path A
48. e greater than 6 0 5 volt peak to peak exists the power leads a surge ripple filter must be employed The following total lead wire resistances are the maximum permissible for maximum track circuit length and minimum receding ringing distance l Transmitter to Rails 15 ohm 25 Receiver to Rails 0 15 ohm 3 Receiver to Relay 25 00 ohms 4 Battery to Receiver 0 5 ohm 5 Battery to Transmitter 0 15 ohm 6 Coupling Unit to Rails Each End 0 15 ohm 6134 2 6 MINUMUM R jara RED IMPEDANCE IN OHMS OF CIRCUIT A B C D AH APPROXIMATE EXISTING IMPEDA PE D RESISTANCE OF A 8 AND C D ANG pt E TT F 55 N DISTANCE d IN FEET Figure 2 2 Requirements for Blocking Reactor 6134 p 2 7 4 D UNION SWITCH amp SIGNAL AND DC REACTOR AFO IIC TRANSMITTER OR i RECEIVER DC BATTERY VIEW A 1 REACTOR VIEW 2 REACTOR VIEW REACTOR AND DC L4 REACTOR VIEW Figure 2 3 Applications of Reactor to AFO IIC Track Circuits 6154 p 2 8 UNION SWITCH SIGNAL D 2 6 LIGHTNING PROTECTION 2 6 1 General In order to limit surge voltages from lightning it is important to use suitable arresters between any points of exposure This is best accomplished using a shunt arrester
49. e beads L2 L8 were inserted in line with the leads from the receiver box Capacitors Cl4 C17 are used for additional decoupling 1 provides reverse battery protection and C4 provides power surge protection at the battery connection Network R12 R13 provides a reference voltage for ICl while C3 further dampens any noise riding the battery line 5 3 2 Required Test Equipment Device Specifications Oscilloscope Tektronics Bandwidth 50 MHz 2215 or equivalent Time base 05 usec to 5 sec div Time base accuracy 4 Voltage accuracy 4 Sensitivity 2 mV div Frequency Counter HP Freq range 5 Hz to 2 MHz 5307 or equivalent CPM Mode 50 to 100 counts minute Input impedance 1 0 megohm Input sensitivity min 10 mV RMS Power Supply 6267B or Voltage range 0 to 40 equivalent Current range 0 to 10 amps Ripple at any given output within above range less than 10 mV P P DC Voltmeter Simpson 260 Voltage range 0 to 5000 V or equivalent Input resistance 20 000 ohms Vdc 5 000 ohms Vac Accuracy 2 Ohmmeter resistance range 0 to 20 megohms 3 ranges Ohmmeter accuracy 2 F S dc 3 F S ac Function Generator Internal AM capability Wavetek 146 or equivalent Frequency range 0005 Hz to 10 Mhz Output impedance 50 ohms Output voltage 10 volts P P into 50 ohm load Sine distortion Less than 0 5 10 Hz to 100 Relay US am
50. ectifies the signal to provide an output to operate an external relay contacts of the relay are then employed in the same fashion as conventional track relay contacts transmitter and receiver require a dc power source for operation 6134 p 1 1 gt v UNION SWITCH amp SIGNAL UNOCCUPIED TRACK CIRCUIT i OCCUPIED TRACK CIRCUIT 90911011 POWER LL SOURCE RELAY 2 CONTROLLED CONTROLLED CIRCUITS CIRCUITS 5 4 ERE ENERGIZED AFO SIGNAL SHUNTED DEENERGIZED Figure 1 1 Typical AFO IIC Track Circuit Operation 2 TRACK SIGNAL 1 TRACK SIGNAL TRANSMITTER 2 FREQUENCY TRANSMITTER 1 FREQUENCY 11 ume 01 22 me het AFO IIC TRANSMITTER RECEIVER 2 1 TRANSMITTER RECEIVER HIGHWAY CROSSING Figure 1 2 Typical AFO IIC Highway Crossing Layout With Overlapping Track Circuits 6134 p 1 2 UNION SWITCH amp SIGNAL series AFO IIC track circuits be superimposed track section see Figure 2 3 Each track circuit is designed to operate independently without interference from other AFO IIC or dc track circuits This is most important where adjacent highway crossings have overlapping approach limits Also it allows an overlap at the crossing for an island circuit as shown in Figure 1 2 1 2 3 Circuit Protection Surge protec
51. ensitivity 6 0 3 millivolts RMS 6134 p 5 15 UNION SWITCH amp SIGNAL FREQUENCY COUNTER FUNCTION GENERATOR CARRIER AND MODULATION AUDIO FREQUENCY VOLTMETER Figure 5 8 Receiver Test Set Up Using Amplifier 6134 p 5 16 DC POWER SUPPLY 12 1 VDC AUDIO POWER AMPLIFIER OSCILLOSCOPE 1 RECEIVER 5 2 1 Function Generator and Audio N 48 9 PET LT 5 Connection Point Numbers 8 17 17 INPUT FILTER OO OO OO DEMODULATOR AND 451522 53 iim RELAY DRIVER PCB FREQUENCY 2 UN451522 68 8 EN LIL Lt ttt FREQUENCY HZ da OO M i 7 Ore i 1 S 1 HE 6 di E 5 CC 1 IF o0 R10 10 o 3 e Nus old 13 13 JO LO m m C af 7 s E Figure 5 9 Physical Locations of Receiver Test Points Q 8 HILIMS UNION SWITCH amp SIGNAL att 4 SI 0 oen om 5 5 pm h 1 xx89 zzS15EN 2516 1 WIAQUO 13s 1000430 11 104681 1 08808 1 6508 1 1 i i 1 ES ot szo ce t i 0 31990 bi gt H t i
52. g the frequencies the required length of the track circuit must also be considered since the AFO signal attenuation in the track circuit is directly proportional to the frequency Figure 2 1 a block length versus frequency curve shows the maximum effective block length permitted for the AFO IIC equipment NOTE For each coupling unit used in an AFO IIC track cir cuit the effective length of that track circuit is reduced by 500 feet 6134 p 2 3 UNION SWITCH amp SIGNAL Figure 2 1 represents the maximum lengths for adjusting the track circuit at 3 5 and 20 ohms ballast resistance and does not consider P the increase in receding ringing distance resulting from a drop in 2 ballast resistance 2 2 RECEIVER RELAY E The AFO IIC receiver incorporates an electronic level detector which is designed to simplify relay requirements US amp S relays DN 22BH or the PN 150BH are recommended for the AFO IIC receiver relay However other 400 to 500 ohm relays such as the US amp S PN 150B N322500 701 or the DN 11B N274069 be used with the AFO II equipment 2 3 TRACK COUPLING UNITS Three Track Coupling Units are provided to pass any one of the six frequencies in the group for which either is tuned and connected refer to Table 2 1 fourth Track Coupling Unit is capable of passing four frequencies All other frequencies are rejected Refer to section 6 X for part number and frequency cross references See Figures
53. hibits passage of any unwanted signals such as harmonics 1 5 3 Specifications Input Voltage 9 5 16 2 Vdc Input Current 0 40 06 amp at 12 V input 2 ohm output load Output Voltage 5 0 0 4 VP P during ON period 2 Ohm load 12 0V battery of modulation Output Impedance 1 Ohm Nom at center of assigned frequency Operating Frequencies Refer to Table 3 1 Temperature Range 409C to 719 409F to 160 F Surge Protection Built in Min Ballast Resistance 3 ohm 1000 Ft 6134 p 1 6 UNION SWITCH amp SIGNAL D RECEIVER OUTPUT TRANSFORMER WITH RESONANT OUTPUT CIRCUIT EMITTER DRIVER FOLLOWER TRANSFORMER AMPLIFIER FOLLOWER AMPLIFIER BUFFER STAGE WITH CURRENT GAIN EMITTER CARRIER SUMMING MODULATION OSCILLATOR CIRCUIT RATE WITH TUNED OUTPUT OSCILLATOR TRANSMITTER BOARD Figure 1 4 AFO IIC Transmitter Block Diagram 6134 p 1 7 D UNION SWITCH amp SIGNAL l 6 AUXILIARY EQUIPMENT 1 6 1 Track Coupling Units N451052 19XX A Track Coupling unit is used when the AFO signal must be passed around insulated joints and the existing track circuit energy must be blocked This unit uses transformer coupling to pass the AFO signal to the next track section Redundant blocking of dc passage is accomplished by both the transformer and series components to provide vitality of the system When insulated joints need to
54. input is a low impedance series tuned circuit which rejects dc or low frequency ac voltages present from any existing track circuit The filtered AFO signal is then applied to a gain adjustment circuit which includes a sensitivity potentiometer The gain is adjusted at installation to establish the track circuit shunting sensitivity The signal is then applied to a tuned step up transformer then demodulated by the envelope detector Its output is then fed into the impedance matching circuit to provide a low impedance source to the modulation band pass filter on the next board Rev 6 85 6134 p 1 3 4 UNION SWITCH amp SIGNAL TRANSMITTER AFO RECEIVER HIGH SEL TUNED BANDPASS STEP UP FILTER ADJUSTMENT TRANSFORMER SENSITIVITY IMPEDANCE ENVELOPE MATCHING STAGE DETECTOR INPUT FILTER BOARD MODULATION AMPLIFIER REVERSE FREQUENCY RECTIFIER BATTERY amp BANDPASS amp SURGE FILTER OSCILLATOR NEG DC MAKER PROTECTION DEMODULATOR RELAY DRIVER BOARD BATTERY 2 e AFO BATTERY 400 500 TRACK RELAY TYPICAL US amp S PN 150B PN150BH DN 22BH DN 11B Figure 1 5 AFO IIC Receiver Block Diagram 6134 p 1 4 UNION SWITCH amp SIGNAL 27 1 3 3 Demodulator Relay Driver Board N451522 68XX See Figure 2 3 At the Demodulator Relay Driver board the recovered envelope of the signal is filtered to pass only the assigned modulation
55. inuous train detection in signal systems The AFO IIC Transmitter signal is amplitude modulated to provide immunity to noise in the rails 11 AFO IIC Transmitters and Receivers are fully transistorized and operate from a dc power supply ranging from 9 5 to 16 2 volts The term audio frequency refers to the frequencies within the audio range 20 20 000 Hz term overlay refers to the AFO signal superimposed or overlaid on the existing track circuit All circuitry in the transmitter and receiver units is mounted on printed circuit boards The boards are hard wired to external terminals and enclosed in sheet steel housings designed for shelf wall or rack mounting terminal strips are provided for external circuit connections 1 2 2 Track Circuit Operation The AFO track circuit detects the presence of a train through 1055 of the audio frequency signal which is shunted by the train axles This is shown in Figure 1 1 The track circuit is composed of transmitter receiver and receiver relay The transmitter introduces an audio signal of a specific assigned frequency into the track through two wires connected directly to the rails This point defines one end of the AFO track circuit The receiver only responds to a specific assigned frequency is also connected to the rails with two wires this point defines the other end of the AFO track circuit Upon receiving the proper frequency the receiver detects amplifies and r
56. is overlayed on AFO IIC track circuits a blocking reactor may be required to prevenet shunting the AFO signal When the Microcode is confined within the AFO track circuit blocking reactor No 1 listed below is recommended Where the Microcode in a particular application is operating near the upper limit of its distance range see Microcode application service manual No 6195 blocking reactor No 2 listed below is recommended The blocking reactor is installed in series with one of Microcodes track leads The determination when to use blocking reactors in Microcode applications outside the confinement of the AFO track circuit is decided by the following steps 1 knowing the frequency of the adjoining AFO IIC unit 2 And by calculating the critical distance D Diagram beyond which no reactor is required at a particular AFO frequency using the formula below 1300 in feet Where KHz Example AFO IIC frequency is 0 885 KHz Thus Distance 1300 1382 feet 885 This means that when a microcode is located within 1382 feet from either a AFO IIC transmitter or receiver 885 Hz it is required to have a reactor in series with one of its track leads Here again the selection of the No 1 reactor is recommended However if as described above the block length of the Microcode is near its upper limit of its advertised distance range the use of No 2 blocking reactor will suffice In fact if the Microco
57. l become increasingly large due to compiling of variations toward the front or carrier modulator end of the transmitter DC voltage levels of all measured ac signals must fall within 10 of those levels shown in the waveform of the test point in question unless otherwise noted Certain tests are verified with oscilloscope waveform diagrams oscillograms which represent the typical waveforms and voltage levels present at various points in the AFO IIC Transmitter circuitry The oscillograms are shown in Figure 5 5 Figures 5 3 and 5 4 show the physical and schematic locations respectively of the receiver test points The oscillograms represent typical 6134 p 5 2 UNION SWITCH SIGNAL 437 RIT 1009 1 05 IN4003 R42 012 330K 00 33UF Ri 1200 c6 82UF P 2N2270 S D1 144003 1 277 02 Di 1257 iN4730A R13 04 150K 1 4003 5 2901 THRU 2920 N 02 194003 2 e Ss EN At ab uot 0 AN TRANSMITTERS WITH SUFFIXES 2901 THRU 2920 NOW 2965 THRU 2987 REQUIRE A SINGLE 451522 45 THE THI 15 A VITAL SAFETY CIRCUIT ANY UNBRACKETED NOMENCLATURE IS VALID CIRCUIT CHANGE OP SUBSTITUTION SPECIAL HIGH POWER APPLICATION TRANSMITTERS WITH SUFFIXES 2935 THRU 2944 REQUIRE TWO PCB S CAN COMPROMISE E SAFE PER F451522 45XX AND 451522 90
58. multimeter should have 10 000 ohms per volt minimum input impedance a 0 2 5 Vac RMS range and a 0 50 Vdc range 4 3 INSPECTION AND INITIAL CHECKS The following inspections and checks may be performed in accordance with the customer s scheduled inspections of related field equipment 1 Check the condition of the cases terminals and wiring for impact damage cracks loose components frayed insulation etc 2 Check all lightning arresters for any clearly damaged or destroyed units Use the multimeter to check the continuity of the intact arresters shorted arrester should be replaced 3 Using a dc voltmeter check the battery voltage for 9 5 to 16 2 volts The voltage reading must be within this range for proper operation of the AFO equipment 4 Shunt the track circuit and check the control relay voltage with dc voltmeter Compare it with the last recorded reading 6134 p 4 1 _ SWITCH SIGNAL 4 4 MAINTENANCE PROCEDURES 4 4 1 Equipment Substitution Method Where a spare transmitter and receiver of the correct frequency are available the following method may be used to determine the cause of failure or improper operation of an AFO track circuit installation a Check the battery for a reading of 9 5 to 16 2 volts b Substitute a spare transmitter the original and check operation operation is not correct go to Step step c c Substitute a spare receiver for the original adjus
59. p S PN 150B N322500 901 PN 150BH N322511 006 Rev 6 85 6134 5 13 UNION SWITCH SIGNAL Audio Power Amplifier MacIntosh Model MC2100 or equivalent Resistors 10 equivalent x Dale RS 5 equivalent Potentiometer Required only for test set up 5 3 3 Test Set Ups An AFO IIC Receiver unit under Power output 20 5 volts RMS across 4 ohm load Output impedance 4 ohms Rated power band 20 to 20 000 Hz Total harmonic distortion Less than 0 25 7 5 Ohm 1 Watt non inductive 1 3 Ohm 1 Watt non inductive 2 0 Ohm 10 Watt 1 tolerance 1 0 Ohm 5 Watt 1 tolerance 1 Ohm with matched transmitter and receiver test requires a an input signal equivalent to the signal supplied by the transmitter unit at the field installation and b that this signal have the proper impedance This may be done with the matching AFO IIC Transmitter or a function generator Figure 5 7 shows the equipment set up for the matched transmitter and receiver units This method of checking receiver sensitivity in this manner is not very accurate In general the transmitter is not an ideal source due to the makeup of the output stage To avoid crossover distortion the bases of the transmitter output stage consisting of Q6 and Q7 are biased slightly positive by means of TRANSMITTER RECEIVER m MATCHING FREQUENCY POWER SU
60. re Follow Up BLOCKING REACTOR ovn dt NI fes c Und UN PA 5 5 5 5 5 5 5 5 5 5 5 5 Ss 5 Du 5 Da 25 5 5 m Ur deg Ro Po w CO CO D H APPENDIX A Parts List UNIT PART NUMBERS Frequency Classed Units Miscellaneous Units AFO IIC RECEIVER BASIC ASSEMBLY RECEIVER PRINTED CIRCUIT BOARDS Standard Vs Frequency Determining Components Input Filter 451522 5302 to 5321 Standard Components Input Filter PCB N451522 5302 to 5321 Frequency Determining Components Demodulator Relay Driver PCB N451522 6802 to 6808 Standard Components Demodulator Relay Driver PCB N451522 6802 to 6808 Frequency Determining Components AFO IIC TRANSMITTER BASIC ASSEMBLY TRANSMITTER PRINTED CIRCUIT BOARD Transmitter PCB N451522 4502 to 4521 Standard Components Transmitter PCB N451522 4502 to 4521 Frequency Determining Components TRACK COUPLING UNIT BASIC ASSEMBLY TRACK COUPLING UNIT COMPONENT BOARD 451053 580 Standard Components Frequency Determining Components Lo C9 Co 9 Ne Nr gt FP gt gt gt gt gt PPP NN gt Ne 11 1 tas it f i UO 01 1 tit t tot PP RNR i
61. roup located in Table 3 1 are assigned When not assigned these wires should be connected to the spare terminal 4 Reassemble the unit in its sheet metal cover ce Table 3 1 Coupling Unit Internal Terminal Board Connections Frequency Hz Connect Wire Color On Terminal Black P Brown to White to Blue to Term Term Term Q0 O HP Ov QU fO d UDIN ED gt gt RUD IND ES doa UO INO gt SS IND ED 6134 3 2 UNION SWITCH amp SIGNAL D TRACK INPUT YA TRACK OUTPUT LEAD 1 A gt LEAD 1 gt eus C KD C 2 C3 gt S gt C CO c xs C 3 gt CN gt C gt gt gt TRACK INPUT TRACK OUTPUT LEAD 2 LEAD 2 TRACK INPUT LEAD 1 gt lt Pp gt CX 52 gt gt C lt gt K2 ons gt CA C TRACK INPUT TRACK OUTPUT LEAD 2 LEAD 2 CIRCUIT DIAGRAM FOR BOARD 4 451053 5804 Figure 3 2 Track Coupling Unit Internal Wiring Connections Groups 1 and 2 N451052 1901 and 1902 6134 p 3 3 4 UNION SWITCH amp SIGNAL TRACK INPUT c 52 TRACK OUTPUT LEAD 1 LEAD 1 3 lt 2 gt cd Cc x Q KO gt 2 lt gt 62 xs 22 52 KO TRACK INPUT TRACK OUTPUT LEAD 2 LEAD 2 TRACK INPUT TRACK OUTPUT LEAD
62. should be taken with oscilloscope The output should be approximately 5 0 volts P P during the on period of the modulation If a VOM is used to read the output then the voltage should be above 0 9 volt RMS the voltage is less than these values the transmitter is faulty and should be replaced neither the transmitter or receiver is faulty the problem may be in the track leads or connections or in the rail bond connections 6134 p 4 2 UNION SWITCH SIGNAL D SECTION V SHOP MAINTENANCE 5 1 GENERAL Because of the vital functions performed by the AFO IIC equipment shop maintenance should only be performed by properly equipped and trained personnel Maintenance procedures in this section consist of separate verifications of the transmitter receiver and track coupling units transmitter and receiver test procedures begin with the units fully assembled units are then disassembled during these procedures to access circuit board test points When the AFO IIC transmitter or receiver is disassembled the maintainer should examine the circuit boards for the condition of the fuses burned wires or components loose or missing components broken component leads and broken wires Refer to Appendix A for wiring diagrams of these units The circuit boards should also be checked for physical damage Faulty units should be returned to US amp S for repair and or recalibration 5 2 TRANSMITTER UNIT N451052 29XX 5
63. sitivity and a 0 10 volt range across the relay terminals 4 When power is applied a dc voltage of at least 5 5 volts should be developed across the receiver relay terminals the voltage is not at least 5 5 volts loosen the lock nut on the receiver s sensitivity adjustment and turn the shaft clockwise until the voltage is as specified Then lightly tighten the lock nut at least 5 5 volts cannot be obtained check all connections on the transmitter receiver track coupling units and reactors 6134 p 3 5 SN 2 union SWITCH SIGNAL NOTE The AFO IIC receiver incorporates an electronic level detector in the relay driver circuit The hysteresis of this circuit when operated near its threshold is relatively narrow and therefore quite sensitive to en vironmental changes From a maintenance standpoint it would be tedious to readjust the circuit every time a small change has taken place in the intervening per iod Therefore it is recommended that the AFO IIC approach track circuit be initially adjusted for a shunting sensitivity in excess of 06 ohms Typically a value between 07 and 10 ohms is desirable 5 Connect a 0 08 ohm resistance shunt across the rails at the receiver track connections Use rail clamps to insure good contact NOTES In no case should the AFO IIC Receiver be adjusted for a shunt of less than 0 06 ohm resistance a higher Resistance shunt
64. t Numbers 1 m 8 8 an Oli 03V St 23loyNn Physical Locations of Transmitter Test Points Figure 5 3 6134 p 5 6 5 7 V 7 6134 ASE SERN ANSP ZEC Nes 6 2268 14 UNION SWITCH SIGNAL D 10 eeu 1 Schematic Locations of Transmitter Test Points 95 RT 2 Q 5 4 Ay 4 el Q UNION SWITCH amp SIGNAL CONNECTION PONT buh tl 4 mu flu ___ _ m ILL POINT 2 VERT 2 0 V DIV an E OV CONNECTION lt io ponas S pA TN VERT 08 viov ET TE PE POINT 4 Figure 5 5 6134 5 8 0 5 CONNECTION owes 11131111 CONNECTION POINT 6 VERT 2 0 V DIV CONNECTION POINT 7 VERT 1 0 1 LA DL IM CONNECTION POINT 4 EXPANDED WAVEFORM VICINITY OF SCOPE DIVISIONS 2 AND 5 Transmitter Test Oscillograms 5 2 5 Steps JT Operation
65. t per section 3 2 and check operation operation is now correct reconnect the original transmitter and check operation again both receiver and transmitter could be defective Readjust the track circuit again per section 3 2 d If neither the battery transmitter or receiver are faulty check the track bootleg connections and the AFO relay defec tive Track Coupling Unit may be a cause of the difficulty Check all terminals used in the coupling unit to ensure proper connec tion Refer to section 3 1 3 for coupling unit wire connections 4 4 2 Voltage Measurement Method Receiver and transmitter output voltages may be measured to determine the condition of these units as follows a Check the battery voltage for 9 5 to 16 2 volts b Using the 10 000 ohms per volt dc voltmeter measure the receiver output voltage at terminals 5 and 6 for a value equal to or higher than the pickup voltage of the AFO relay this voltage is at the pick up voltage or above the difficulty may be in the AFO relay or wiring between the unit and the relay C the voltmeter reading at terminals 5 and 6 shows low voltage recheck the track circuit adjustment per section 3 2 If the proper receiver output voltage is not obtained discon nect the transmitter from the track circuit Place a 2 0 ohm load across the transmitter output terminals and measure the transmitter output ac voltage Since the signal is modulated the reading
66. t procedure for the Track Coupling unit consists of a measurement of the output level across output terminals 3 and 4 A function generator and audio power amplifier are used to simulate the track signal Adjustments of this input are included in the test to allow a certain margin of error in the tuning of the unit 6134 p 5 23 SN union SWITCH amp SIGNAL FUNCTION FREQUENCY GENERATOR COUNTER TRACK POWER COUPLING AMPLIFIER UNIT AUDIO FREQUENCY VOLTMETER Figure 5 12 Track Coupling Unit Test Set Up 5 4 4 Test Procedure Operation Verification Adjust the audio power ampli fier until the input level across AAR terminals 1 and 2 equals 1 0 01 volts RMS Using the audio frequency The meter should show a read voltmeter measure the out ing between 0 29 and 0 75 put level across the 1 0 ohm volts RMS for units with suf 5 watt load resistor fix numbers 5801 and 5802 and 0 41 to 1 0 volts RMS for for units with suffix numbers 5803 and 5804 this test is not successful continue with step 3 6134 p 5 24 6 85 UNION SWITCH SIGNAL D OPeration Verification Using the vernier control The frequency which creates a the function generator ad maximum output should be with just frequency until the out in 0 7 of the selected fre put level across the 1 0 ohm quency of the unit under test load resistor is at a maximum If this test is not successful
67. tion is provided within the receiver and transmitter for both the dc line and track lead inputs Refer to Section 2 6 for lightning protection requirements Reverse polarity protection is also included If battery polarity is accidentally reversed a protective fuse will blow which disconnects the unit from the battery supply This is intended to prevent power loss to other equipment 1 3 AFO IIC RECEIVER N451052 31XX 1 3 1 General The AFO IIC Receiver operates over a dc battery voltage range of 9 5 to 16 2 volts In case of battery failure the receiver is designed to not be damaged from the battery charger rectifier or cause the receiver relay to be falsely energized A sensitivity adjustment is built into the receiver unit to obtain the proper shunting characteristics for each track circuit The AFO IIC Receiver is housed with all circuit components mounted on two printed circuit boards Input Filter and Demodulator Relay Driver Both boards are mounted on the top plate by means of a support bracket and enclosed within the housing The design of the AFO IIC Receiver provides increased immunity from potential traction control choppers and traction power supply interference in electrical railroads The receiver design also provides increased immunity from radio interference 1 3 2 Input Filter Board N451522 53XX See Figure 1 3 The signal from the track is applied to a high selectivity band pass filter on the Input Filter board Its
68. tly or indirectly affect the tuning of the narrow band pass filter demodulator circuit and gain adjustment 6134 p 5 22 UNION SWITCH SIGNAL 0 5 4 TRACK COUPLING UNIT 5 4 1 Required Test Equipment Device Specifications Frequency Counter HP Freq range 5 Hz to 2 MHz 5307A or equivalent Mode 50 to 100 counts minute Input impedance 1 0 megohm Input sensitivity min 10 mV RMS Function Generator Internal AM capability Wavetek 146 or equivalent Frequency range 0005 Hz to 10 Mhz Output impedance 50 ohms Output voltage 10 volts P P into 50 ohm load Sine distortion Less than 0 5 10 Hz to 100 Khz Analog Voltmeter HP 10 Hz to 10 Mhz true RMS voltmeter 3400A or equivalent Voltage range 1 mV to 300 V F S 12 ranges DB range 72 to 452 dBm Input impedance 10 megohms Audio Power Amplifier Power output 20 5 V RMS across MacIntosh Model MC2100 or 4 ohm load equivalent Output impedance 4 ohms Rated power band 20 to 20 000 Hz Total harmonic distortion Less than 0 25 Resistor Dale RS 5 or 1 0 Ohm 5 Watt 1 tolerance equivalent US amp S 1587796 5 4 2 Test Set Up The test equipment set up for the track coupling unit is shown in Figure 5 12 signal generator should be adjusted to the frequency of the coupling unit under test Refer to Table 3 1 and Figures 3 2 and 3 3 for frequency data 5 4 3 Test Procedure Comments The tes
69. ured with an oscilloscope across terminals 3 and 4 of the receiver the audio power amplifier use only the lowest output impedance tap preferably 2 0 or 4 0 ohm Leave power off and the receiver disconnected until specified in the test procedure When turning on power set the power supply to its minimum voltage then adjust to 12 0 1 Vdc 5 3 4 Procedure Comments The following procedure is based on the test set up shown in Figure 5 8 Certain tests are verified with oscilloscope waveform diagrams oscillograms which represent the typical waveforms and voltage levels present at various points in the AFO IIC Receiver circuitry The oscillograms are shown in Figure 5 11 Figures 5 9 and 5 10 show the physical and schematic locations respectively of the receiver test points The oscillograms represent typical waveforms and voltages generated in the AFO IIC receiver Small variations in the actual waveforms and voltages may occur with the particular unit under test These are acceptable for test results NOTE The oscilloscope horizontal sweep rate settings re quired to produce the represented waveforms will vary depending on the selected frequency and code rate of the AFO II unit under test Except where noted the oscilloscope time base is the same for all waveform diagrams Battery voltage 12 4 1 Vdc oscillo Scope probe input impedance is 10 megohms The receiver input signal is approximately twice the indicated input s
70. utput transformer D3 and 04 bias the bases of Q6 and Q7 slightly positive to avoid crossover distortion in the output The output filter of Cll and L2 is tuned to the carrier frequency 6134 p 5 1 D UNION SWITCH amp SIGNAL 5 2 2 Required Test Equipment Device Specifications Oscilloscope Tektronics Bandwidth 50 MHZ 2215 or equivalent Time base 05 usec to 0 5 sec div Time base accuracy 43 Voltage accuracy 43 Sensitivity 2 mV div Frequency Counter Hewlett Freq range 5 Hz to 2 MHz Packard 5307A or equivalent Mode 50 to 100 counts minute Input impedance 1 0 megohm Input sensitivity min 10 mv RMS Power Supply HP 6267B or Voltage range 0 to 40 Vdc equivalent Current range 0 to 10 amps Ripple at any given output within above range less than 10 mV Resistor Dale RH 10 or equi 2 0 Ohm 10 Watt 1 tolerance valent US amp S J735519 0624 5 2 3 Test Set Up Figure 5 2 shows the test set up for the AFO IIC Transmitter Before turning on the power supply make certain the voltage adjustment is set to minimum Then turn power supply on and adjust to 12 0 1 Vdc 5 2 4 Procedure Comments The AFO IIC transmitter is set by adjusting the peak to peak output voltage to relatively narrow limits across a fixed 2 0 ohm load This allows the voltage spread on various units to be small near the output stage of the transmitter This spread however wil

1 - Ansaldo STS

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