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The TTU-205 Series Pressure-Temperature Test Sets are generate regulated Pitot (Pt) and Static (Ps) pressure and simulate precise temperatures for evaluating aircraft pneumatic instruments, air data systems and auxilary equipment. The test sets can be used to conduct dynamic tests, quantitative calibration tests and pneumatic leak tests.These test sets can be used to test, certify, calibrate, and trobleshoot aircraft pitot-static systems or associated pneumatic flight control systems. One of four operating modes can be selected by the front panel control switch:
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Self Test - in this mode the test set is exercised by the microprocessor through an extensive check of all external lights and displays, as well as an internal check of the operating hardware and software |
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Cal Test - this mode initiates a confidence test within the test set. Under program control one channel is put into the control mode and the other the monitor mode. The unit then automatically cycles through three specific pressures controlled by one channel and monitored by the other. The transducer signals are compared by the microprocessor and if they do not agree within a predetermined amount, a fault is indicated |
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Auto Exercise - this mode provides for automatic cyclin of both channels to be certain that they are operating within their required tolerance. |
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Normal Operate - in this mode the test set provides the commanded output pressures. |
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Protection Features
These test sets contain several safety features to ensure fail-safe operation. These includes an automatic startup procedure which protects the instrument under test from dangerous surges and transients. Proper startup is therefore completely independent of the prevailing ambient atmospheric pressure. Monitoring of the overall operation of the test sets are continuously performed by the micro-processor. Should a failure occur in either the hardware or the software the unit automatically goes into REST and the unit under test is vented at a controlled rate. Mach Limit setting ability is also provided to protect the UUT.
Controls for modulating the two channels as well as switches to perform the leak test on the UUT. The test set is a single integral unit, self-contained within its case. It has a cover compartment for storage of all accessories (Power Cord, Ps hose, Pt hose, Vacuum hose, and Ground Strap). All interior components of the test set, including the pressure/vacuum pump assembly, are mounted in a single frameworkattached to the control panel, so that they can be removed with the control panel and be completely exposed for maintenance. |
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Characteristics
The key elements in the test sets are the two resonant frequency transducers which sense the pressures at the Pitot and Static output ports. The microprocessor based electronics compare the commanded pressures and pressure rates with the transducer pressure signals and in turn drive the two pneuamtic servo control valves to establish the correct pressure and pressure rates at the output ports.
The commanded pressure and pressure rates are selected by their respective thumbwheel switches (except for the TTU-205C/E) on the front panel. The measured pressures are disaplyed on the six digital incadescent displays (not on TTU-205C/E). All commands and displays are in feet or knots in their respective channel. |
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| TTU-205 Series Test Set Models |
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