1、 外 文 翻 译 毕业设计 题目： 多传感器检测系统信号处理研究 原文 1： 911plus CTD SYSTEM OPERATING AND REPAIR MANUAL 5-1 译文 1： 911plus CTD 系统的操作和维修手册 5-1 原文 2： 911plus CTD SYSTEM OPERATING AND REPAIR MANUAL 5-2 译文 2： 911plus CTD 系统的操作和维修手册 5-2 1-3 TROUBLE DIAGNOSIS AND REPAIR (UNDERWATER UNIT PROBLEMS) (原文 1) LIFE-THREATENING HIG
2、H VOLTAGES ARE PRESENT IN BOTH DECK UNIT AND UNDERWATER UNIT WHEN POWER IS ON. THESE HAZARDOUS VOLTAGES PERSIST FOR UP TO ONE MINUTE AFTER REMOVAL OF POWER. THE BEST WAY TO PROTECT AGAINST ELECTRICAL SHOCK IS TO DISCONNECT THE AC POWER CORDS FROM THE REAR PANEL OF THE DECK UNIT, THEN WAIT A FULL MIN
3、UTE BEFORE ATTEMPTING SERVICE. ALWAYS DISCONNECT THE AC POWER CORD BEFORE CHECKING FUSES! For protection of the circuitry, we also recommend that AC power be removed and a 1 minute period for supply capacitor discharge be allowed before opening housings, changing connections, removing or inserting c
4、ircuit cards, or otherwise working on the equipment. If the data telemetry is OK (deck unit data light is on and error light off) but one or more channels is faulty, see Section 5-2 (Sensor Problems) before proceeding with work on the underwater unit； the problem may be a defective sensor. Read Sect
5、ion 4-1 which describes the operation of the underwater unit circuitry. Refer also to the section titled schematics which contains the underwater unit schematic diagrams. All voltages are measured relative to pin 2 of any plug-in card； this is main signal/power ground for the underwater unit. 5-1.1
6、UNDERWATER UNIT COMPLETELY INOPERATIVE Make sure that the deck unit is supplying the proper sea cable voltage (250 volts). If there is no sea-cable voltage, the seacable rear panel fuse may be blown. With SEARAM units, see that SEARAM is supplying the proper voltage to the CTD (12 - 15 volts). Look
7、for the presence of the telemetry waveform across the sea cable. USE EXTREME CAUTION IN PERFORMING THIS OBSERVATION. THE SEA CABLE VOLTAGE IS POTENTIALLY LIFE-THREATENING! ALLOW 1 MINUTE AFTER POWER-DOWN FOR POWER SUPPLY DISCHARGE BEFORE MAKING CONNECTIONS TO THE SEA CABLE OUTPUT CONNECTOR. If the t
8、elemetry waveform is present, the trouble is probably in the deck unit. If the telemetry waveform is not present at the deck unit, measure the sea cable current which will be in the range of 50 to 220 milliamperes depending on the underwater unit configuration. If the sea cable voltage is present, b
9、ut no current is being drawn by the underwater unit, there is either a break in the sea cable, or an open circuit in the cable interface circuitry inside the underwater unit. Assuming that there is no break in the sea cable, turn off the deck unit power, refer to Section 6-1 and open the Underwater
10、Unit housing, but leave the electronics chassis connected to the top end cap. Restore deck unit power and measure the internal supply voltages (relative to pin 2): +5, +15 and -15 at pins 1, 5, and 3 respectively of the Analog interface boards. If there is no voltage at any point on the backplane, t
11、he sea cable interface circuitry is either defective or is not receiving power from the sea cable. Check that the Sea-cable Interface is receiving the correct input voltage (250 volts). If no voltage is present at the inputs to the DC/DC converters, the series pass transistor Q1 on the sea-cable int
12、erface board may be open. If the +5, +8, +15, or -15 volt levels are absent or in error by more than about 0.5 volts, remove all the underwater unit plug in printed circuit boards. Check the power supply levels again - if these are now ok, the problem is probably in one of the plug-in boards. Start
13、plugging boards in, beginning with the Transmitter (top) board. (Turn off power and wait one minute for supply discharge before plugging in each board). If a board is found which appears to cause the drop in supply voltage, refer to the circuit description in Section 4-1 and the boards schematic dia
14、gram. Check the board for dead shorts at the power input pins -an IC or one of the power supply bypass capacitors may be shorted. Also, carefully examine the board for any metallic material (solder, wire clippings, shavings) which may have inadvertently shorted the printed circuit traces or componen
15、t pins. With the board in the underwater unit chassis, look at the board outputs and inputs for signal irregularities. The logic levels are 5 volt CMOS and should swing the full 0 to +5 volts. If the power supply levels are not ok with the plug-in boards removed, check the backplane wiring for broken connections or wires, and for any shorted connections. Check that the input
