268XA
Service Manual
ii
2
Theory of Operation........................................................................... 2-1
Introduction ....................................................................................................... 2-3
Main Power Supply....................................................................................... 2-5
Secondary Supplies ....................................................................................... 2-5
Out-Guard Overview..................................................................................... 2-5
Microprocessor ......................................................................................... 2-6
FPGA ........................................................................................................ 2-7
Other Bus Devices .................................................................................... 2-8
Serial Devices ........................................................................................... 2-9
Trigger In/Out, Master Alarm................................................................... 2-9
PCMCIA Interface PCA (2686A-4041) ............................................................ 2-10
Backplane PCA (268XA-4001)......................................................................... 2-10
Display Interface ........................................................................................... 2-11
Module Interface ........................................................................................... 2-11
Module Power Supply PCA (268XA-4031)...................................................... 2-11
Digital Input/Output PCA.................................................................................. 2-11
Microcontroller ............................................................................................. 2-12
Data Input Threshold..................................................................................... 2-12
Digital Input Buffers ..................................................................................... 2-13
Digital Output Drivers................................................................................... 2-13
Relay Output Drivers .................................................................................... 2-13
Totalizer Input ............................................................................................... 2-14
Totalizer Enable ............................................................................................ 2-14
A/D Theory of Operations................................................................................. 2-14
A/D Converter PCA Block Description ........................................................ 2-14
Analog Measurement Processor ............................................................... 2-15
Input Protection......................................................................................... 2-15
Input Signal Conditioning......................................................................... 2-15
Analog-to-Digital (a/d) Converter ............................................................ 2-15
Inguard Microcontroller............................................................................ 2-15
Channel Selection ..................................................................................... 2-15
Open Thermocouple Check ...................................................................... 2-16
Analog Input PCA Block Description........................................................... 2-16
20-Channel Terminals............................................................................... 2-16
Reference Junction Temperature .............................................................. 2-16
A/D Converter PCA Circuit Description ...................................................... 2-16
Stallion Chip ............................................................................................. 2-18
Input Protection......................................................................................... 2-18
Input Signal Conditioning......................................................................... 2-18
Function Relays ........................................................................................ 2-18
Channel Selection Circuitry...................................................................... 2-19
DC Volts and Thermocouples Measurement Circuitry............................. 2-19
Ohms and RTD Measurement Circuitry ................................................... 2-20
AC Volts Measurement Circuitry. ............................................................ 2-22
Frequency Measurements ......................................................................... 2-23
Active Filter (ACV Filter) ........................................................................ 2-24
Voltage Reference Circuit ........................................................................ 2-24
Analog/Digital Converter Circuit ............................................................. 2-24
Autozero ................................................................................................... 2-24
Integrate .................................................................................................... 2-25
Deintegrate1.............................................................................................. 2-25
Deintegrate2.............................................................................................. 2-27
Overhead................................................................................................... 2-27
Inguard Digital Kernel Circuitry............................................................... 2-27
Summary of Contents for 2680A
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Page 204: ...268XA Service Manual 7 10 268X FINAL ASSEMBLY alg105f eps Figure 7 1 268XA Final Assembly ...
Page 207: ...Replaceable Parts Parts Lists 7 7 13 2680A DIO alg100f eps Figure 7 3 DIO Module ...
Page 209: ...Replaceable Parts Parts Lists 7 7 15 2680A FAI alg102f eps Figure 7 4 FAI Module ...
Page 211: ...Replaceable Parts Parts Lists 7 7 17 2680A PAI alg103f eps Figure 7 5 PAI Module ...
Page 214: ...268XA Service Manual 8 2 ...
Page 215: ...8 3 8 Schematic Diagrams Figure 8 1 Backplane PCA 2680A 4001 ...
Page 216: ...268XA Service Manual 8 4 Figure 8 1 Backplane PCA cont 2680A 1001 ...
Page 217: ...8 5 8 Schematic Diagrams Figure 8 2 Controller System Power PCA 2680A 4004 ...
Page 223: ...8 11 8 Schematic Diagrams Figure 8 3 Digital I O PCA 2680A 4006 ...
Page 224: ...268XA Service Manual 8 12 Figure 8 3 Digital I O PCA cont 2680A 1006 1 of 3 ...
Page 225: ...8 13 8 Schematic Diagrams Figure 8 3 Digital I O PCA cont 2680A 1006 2 of 3 ...
Page 226: ...268XA Service Manual 8 14 Figure 8 3 Digital I O PCA cont 2680A 1006 3 of 3 ...
Page 227: ...8 15 8 Schematic Diagrams Figure 8 4 Backplane Extender PCA 2680A 4009 ...
Page 228: ...268XA Service Manual 8 16 Figure 8 4 Backplane Extender PCA cont 2680A 1009 ...
Page 229: ...8 17 8 Schematic Diagrams Figure 8 5 Extender PCA 2680A 4010 ...
Page 230: ...268XA Service Manual 8 18 Figure 8 5 Extender PCA cont 2680A 3010 ...
Page 231: ...8 19 8 Schematic Diagrams Figure 8 6 A D Supply Assembly 2680A 4031 ...
Page 232: ...268XA Service Manual 8 20 Figure 8 6 A D Supply Assembly cont 2680 1031 ...
Page 233: ...8 21 8 Schematic Diagrams Figure 8 7 PCMCIA PCA 2680A 4041 ...
Page 234: ...268XA Service Manual 8 22 Figure 8 7 PCMCIA PCA cont 2686 1041 ...
Page 235: ...8 23 8 Schematic Diagrams Figure 8 8 Output PCA 2680A 4062 ...
Page 236: ...268XA Service Manual 8 24 Figure 8 8 Output PCA cont 2680A 1062 ...
Page 237: ...8 25 8 Schematic Diagrams Figure 8 9 A D PFE PCA 2640A 4003 ...
Page 238: ...268XA Service Manual 8 26 Figure 8 9 A D PFE PCA cont 1 of 6 ...
Page 239: ...8 27 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2 of 6 ...
Page 240: ...268XA Service Manual 8 28 Figure 8 9 A D PFE PCA cont 2640A 1003 3 of 6 ...
Page 241: ...8 29 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2640A 1003 4 of 6 ...
Page 242: ...268XA Service Manual 8 30 Figure 8 9 A D PFE PCA cont 2640A 1003 5 of 6 ...
Page 243: ...8 31 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2640A 1003 6 of 6 ...
Page 244: ...268XA Service Manual 8 32 Figure 8 10 A D FFE PCA 2645A 4003 ...
Page 245: ...8 33 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 1 of 6 ...
Page 246: ...268XA Service Manual 8 34 Figure 8 10 A D FFE PCA cont 2645A 1003 2 of 6 ...
Page 247: ...8 35 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 3 of 6 ...
Page 248: ...268XA Service Manual 8 36 Figure 8 10 A D FFE PCA cont 2645A 1003 4 of 6 ...
Page 249: ...8 37 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 5 of 6 ...
Page 250: ...268XA Service Manual 8 38 Figure 8 10 A D FFE PCA cont 700p29_topress zip 2645A 1003 6 of 6 ...
Page 251: ...8 39 8 Schematic Diagrams Figure 8 11 Analog Input Connector PCA 2620A 4004A ...
Page 252: ...268XA Service Manual 8 40 2620A 1004 Figure 8 11 Analog Input Connector PCA cont ...
Page 253: ...8 41 8 Schematic Diagrams Figure 8 12 Display PCA 1 of 1 ...
Page 254: ...268XA Service Manual 8 42 Figure 8 12 Display PCA cont 1 of 1 ...