Theory of Operation
A/D Theory of Operations
2
2-31
Response Packets Returned The inguard returns one response packet for the reference
junction reading if any of the measured channels is a thermocouple channel, followed by
a response packet for each channel measured, returned in ascending channel order,
followed by a response packet for each housekeeping reading specified by the scan
command.
Response Packet Format Each response packet for a Perform Scan command consists
of a floating-point number representing the measurement value, the range used to take the
measurement, the channel number, and the checksum. The floating-point format used is
ANSI/IEEE Std 754-1975 single-precision. Positive and negative overload conditions
cause a value of PLUS_OVLD_VAL (0x7f800000) and MINUS_OVLD_VAL
(0xff800000), respectively, to be returned. A frequency channel whose input frequency is
too low to measure returns 0 Hz. A channel with an open-thermocouple condition causes
the value of OTC_VAL (0x7fc00000) to be returned. The inguard waits until it has
completed all measurement activity associated with a particular scan before beginning the
transmission of the response packets for that scan to the outguard.
The floating-point value returned has a nominal range of -3.0 to +3.0. The outguard must
scale this according to the channel function and range to produce the correct volts or
ohms. For most ranges, a full-range value is returned as +3.0. For example, on the 300
Ω
range, +3.0 represents 300
Ω
. For the 90 mV and 750 mV ranges, however, +3.0
represents 93.26 mV and 0.746083 V, respectively. Also, frequency readings always
return the actual frequency measured and do not require range-scaling by the outguard.
Perform Self-Test
The Command Packet tells the A/D to perform all self tests. Response Packets Returned
always returns a single response packet. The Response Packet Format provides the
following:
•
A/D self-test result, pass or fail.
•
Zero Offset self-test result, pass or fail.
•
Reference Balance self-test result, pass or fail.
•
Ohms Overload self-test result, pass or fail.
•
Open Thermocouple self-test result, pass or fail.
•
Checksum
Return Firmware Version
This Command Packet requests version number of the inguard firmware and always
returns a single response packet.
Response Packet Format The response consists of five ASCII characters (plus the
checksum byte), in the form txxyy, where t is “F” for FFE (FAI) software and “P” for the
PFE (PAI); xx are the two digits of the major version number, and yy are the two digits
of the minor version number (there is an implicit decimal point between the two). Note
that constraining the bytes to be ASCII characters causes the most significant bit of each
character to be a 0, making the response packet always distinguishable from a NAK.
Return Boot Firmware Version
This Command Packet Format requests version number of the inguard boot firmware and
always returns a single response packet.
Содержание 2680A
Страница 6: ......
Страница 12: ...268XA Service Manual vi ...
Страница 18: ...268XA Service Manual 1 2 ...
Страница 48: ...268XA Service Manual 1 32 ...
Страница 96: ...268XA Service Manual 2 48 ...
Страница 98: ...268XA Service Manual 3 2 ...
Страница 105: ...Maintenance DC Fuse Replacement 3 3 9 Fuse 4A 250V Slow 5MM X 20MM Bulk alg111f eps Figure 3 2 DC Fuse Location ...
Страница 106: ...268XA Service Manual 3 10 ...
Страница 132: ...268XA Service Manual 5 2 ...
Страница 194: ...268XA Service Manual 6 48 ...
Страница 195: ...7 1 Chapter 7 Replaceable Parts Title Page Introduction 7 3 How to Obtain Parts 7 3 Service Centers 7 3 Parts Lists 7 4 ...
Страница 196: ...268XA Service Manual 7 2 ...
Страница 204: ...268XA Service Manual 7 10 268X FINAL ASSEMBLY alg105f eps Figure 7 1 268XA Final Assembly ...
Страница 207: ...Replaceable Parts Parts Lists 7 7 13 2680A DIO alg100f eps Figure 7 3 DIO Module ...
Страница 209: ...Replaceable Parts Parts Lists 7 7 15 2680A FAI alg102f eps Figure 7 4 FAI Module ...
Страница 211: ...Replaceable Parts Parts Lists 7 7 17 2680A PAI alg103f eps Figure 7 5 PAI Module ...
Страница 214: ...268XA Service Manual 8 2 ...
Страница 215: ...8 3 8 Schematic Diagrams Figure 8 1 Backplane PCA 2680A 4001 ...
Страница 216: ...268XA Service Manual 8 4 Figure 8 1 Backplane PCA cont 2680A 1001 ...
Страница 217: ...8 5 8 Schematic Diagrams Figure 8 2 Controller System Power PCA 2680A 4004 ...
Страница 223: ...8 11 8 Schematic Diagrams Figure 8 3 Digital I O PCA 2680A 4006 ...
Страница 224: ...268XA Service Manual 8 12 Figure 8 3 Digital I O PCA cont 2680A 1006 1 of 3 ...
Страница 225: ...8 13 8 Schematic Diagrams Figure 8 3 Digital I O PCA cont 2680A 1006 2 of 3 ...
Страница 226: ...268XA Service Manual 8 14 Figure 8 3 Digital I O PCA cont 2680A 1006 3 of 3 ...
Страница 227: ...8 15 8 Schematic Diagrams Figure 8 4 Backplane Extender PCA 2680A 4009 ...
Страница 228: ...268XA Service Manual 8 16 Figure 8 4 Backplane Extender PCA cont 2680A 1009 ...
Страница 229: ...8 17 8 Schematic Diagrams Figure 8 5 Extender PCA 2680A 4010 ...
Страница 230: ...268XA Service Manual 8 18 Figure 8 5 Extender PCA cont 2680A 3010 ...
Страница 231: ...8 19 8 Schematic Diagrams Figure 8 6 A D Supply Assembly 2680A 4031 ...
Страница 232: ...268XA Service Manual 8 20 Figure 8 6 A D Supply Assembly cont 2680 1031 ...
Страница 233: ...8 21 8 Schematic Diagrams Figure 8 7 PCMCIA PCA 2680A 4041 ...
Страница 234: ...268XA Service Manual 8 22 Figure 8 7 PCMCIA PCA cont 2686 1041 ...
Страница 235: ...8 23 8 Schematic Diagrams Figure 8 8 Output PCA 2680A 4062 ...
Страница 236: ...268XA Service Manual 8 24 Figure 8 8 Output PCA cont 2680A 1062 ...
Страница 237: ...8 25 8 Schematic Diagrams Figure 8 9 A D PFE PCA 2640A 4003 ...
Страница 238: ...268XA Service Manual 8 26 Figure 8 9 A D PFE PCA cont 1 of 6 ...
Страница 239: ...8 27 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2 of 6 ...
Страница 240: ...268XA Service Manual 8 28 Figure 8 9 A D PFE PCA cont 2640A 1003 3 of 6 ...
Страница 241: ...8 29 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2640A 1003 4 of 6 ...
Страница 242: ...268XA Service Manual 8 30 Figure 8 9 A D PFE PCA cont 2640A 1003 5 of 6 ...
Страница 243: ...8 31 8 Schematic Diagrams Figure 8 9 A D PFE PCA cont 2640A 1003 6 of 6 ...
Страница 244: ...268XA Service Manual 8 32 Figure 8 10 A D FFE PCA 2645A 4003 ...
Страница 245: ...8 33 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 1 of 6 ...
Страница 246: ...268XA Service Manual 8 34 Figure 8 10 A D FFE PCA cont 2645A 1003 2 of 6 ...
Страница 247: ...8 35 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 3 of 6 ...
Страница 248: ...268XA Service Manual 8 36 Figure 8 10 A D FFE PCA cont 2645A 1003 4 of 6 ...
Страница 249: ...8 37 8 Schematic Diagrams Figure 8 10 A D FFE PCA cont 2645A 1003 5 of 6 ...
Страница 250: ...268XA Service Manual 8 38 Figure 8 10 A D FFE PCA cont 700p29_topress zip 2645A 1003 6 of 6 ...
Страница 251: ...8 39 8 Schematic Diagrams Figure 8 11 Analog Input Connector PCA 2620A 4004A ...
Страница 252: ...268XA Service Manual 8 40 2620A 1004 Figure 8 11 Analog Input Connector PCA cont ...
Страница 253: ...8 41 8 Schematic Diagrams Figure 8 12 Display PCA 1 of 1 ...
Страница 254: ...268XA Service Manual 8 42 Figure 8 12 Display PCA cont 1 of 1 ...
