TT-2D Users Manual - Electronic Devices, Inc.
Contents
1. hold both the A and B buttons and then turn on the power Watch the display and release both buttons immediately after the display shows Cal mode If the buttons are not released quickly the unit will not enter the calibration mode Wait a few seconds after the display changes to ADC xxx on the top line and then press button B to store the ADC calibration value Turn the TT 2D off then back on Check to make sure the impedance reads within 1 ohm If not check the test lead for continuity and repeat the calibration If the reading is still out of specification the unit must be returned to the factory for repair 5 05 OHM METER CHECK Turn the TT 2D on and press button A to put the TT 2D into the DC resistance measurement mode Short the clip leads together and verity that the display reads lt 10 Ohms Open the clip leads and verify the display reads gt 5 M ohms Place a 10 K resistor across the clip leads and verify the display reading is between 9000 and 11000 ohms If the readings are out of specification the unit must be returned to the factory for repair 6 BATTERY TEST The battery should be replaced if the voltage falls below 6 5 volts as indicated on the display when the TT 2D is powered up 6 01 BATTERY REPLACEMENT The battery compartment is located on the back side of the TT 2D Turn the TT 2D face down and remove the battery cover by pressing down and outward with your thumb The cover will th2. indicator and a low impedance over a narrow frequency range The problem is to determine the correct resonant point This will usually be the frequency where the most power is transferred from the face of the transducer Check the energy transfer at each resonant point by pressing on the exact center of the transducer face with a fingertip while observing the impedance displayed on the top line of the LCD The readings will change noticeably with moderate finger pressure The resonant point that produces the most pronounced change of impedance is usually BUT NOT ALWAYS the correct operating frequency for the transducer MEASURING TRANSDUCER IMPEDANCE The transducer impedance at resonance is indicated on the upper left of the LCD The relative phase angle is displayed in the upper right of the LCD A negative sign indicates the load looks capacitive to the TT 2D anda TT 2 User Manual EDI P N 700 013 Page 3 positive sign indicates the load is inductive The lowest impedance reading will usually occur when the relative phase angle displayed is less than ten 3 03 TRANSDUCER DC RESISTANCE Press button A to check the resistance of the transducer The measurement range is from 10 ohms to 5 megohms Piezoelectric transducers that are not transformer coupled should indicate gt 5 Megs of leakage after a few seconds Transformer coupled transducers usually have only a few ohms of resistance and the LCD will indicate lt 10 Ohm
3. output only 2 02 LCD DISPLAY Normally displays the frequency on the lower line and the impedance and relative phase on the upper line Battery voltage and software version are displayed for 3 seconds when the power is turned on 2 03 COARSE FREQUENCY SET KNOB This controls the frequency sent to the transducer from less than 500 Hz to over 500 KHz 2 04 POWER FINE FREQUENCY SWITCH This knob controls the power and is also used to fine tune the frequency setting The frequency range is about 10 of that set by the coarse frequency control 2 05 BUTTONA The main function of this push button switch is to select the resistance measuring mode When this button is pressed the DC resistance of the transducer is displayed in ohms on the bottom line of the display The range covers 10 ohms to 5 megohms Press button B once to return to normal operation 2 05 01 During power up press button A to increase the display contrast 2 06 BUTTONB The main function of this push button switch is to select one of the three frequency ranges The range increments each time this button is pressed Each range covers a decade as shown below 2 06 00 01 Range 1 500 Hz to 5 KHz 2 06 00 02 Range 2 5 KHz to 50 KHz 2 06 00 03 Range 3 50 KHz to 500 KHz 2 06 01 During power up press button B to decrease the display contrast TT 2 User Manual EDI P N 700 013 Page 2 2 07 3 2 06 02 To make a selected frequency range as the default range
4. July 2001 4502 TT 2D USERS MANUAL frequency set 1 INTRODUCTION 2 CONTROL FUNCTIONS 3 GETTING STARTED 4 HOW IT WORKS 5 CALIBRATION 6 BATTERY TEST 7 SPECIFICATIONS 8 WARRANTY AND REPAIR INFORMATION 9 COMMONLY ASKED QUESTIONS Ban Transducer connection Button A l utto as FREQ OHMS LCD display Button B i i m E Power fine s a6 Coarse frequency FREQ ADJ E OFF FINE COARSE WARNING Do not connect XOUCER jack to a voltage source or unit will be damaged f 5p Transducer Test Set MODEL TT2D Electronic Devices inc Chesapeake VA 23322 Figure 1 Control Location TT 2 User Manual EDI P N 700 013 Page 1 1 INTRODUCTION The TT 2D is designed to test acoustic transducers for resonance over the frequency range of 500 Hz to 500 KHz The TT 2D tests all types of transducers including transformer coupled and magnetostrictive devices The load characteristic capacitive resistive or inductive and impedance at resonance are displayed on the two line LCD display The leakage resistance of the transducer can be measured and displayed over the range of 10 ohms to 5 megohms 2 CONTROL FUNCTIONS Refer to figure 1 for the location of the controls discussed in this section 2 01 TRANSDUCER CONNECTION The transducer output connects to the transducer under test WARNING do not connect a source of power to this connector If you do the TT 2D will be seriously damaged This is an
5. are observed All transducers should have a strong indication of resonance at or near the published operating frequency 9 04 01 A multi element transducer with one damaged element may resonate at the correct frequency but the impedance reading will change by a good amount If there is any doubt compare the readings to a known good transducer When making comparative readings both transducers must be tested in air or in water Do not compare the reading in air to the reading in water as there will be a big difference in the measured impedance 9 04 02 If a transducer indicates any measurable leakage less than 5M ohms the wiring should be checked If the wiring is not leaky the transducer should be replaced even if it is working ok on the depth sounder Becuase of the high pulse voltage used a leaky transducer will soon break down internally and cease to operate TT 2 User Manual EDI P N 700 013 Page 7
6. cting the test cable clip leads together The impedance should read within 1 to 1 If the reading is not within this range the unit should be calibrated See the SHORT CIRCUIT LOAD CALIBRATION procedure below for instructions 5 02 CHECKING RESISTIVE LOAD CALIBRATION Turn the TT 2D on and set the frequency to 50 KHz Short the clip leads and verify that the reading is within 1 ohm If the reading is out of spec try the SHORT CIRCUIT CALIBRATION procedure TT 2 User Manual EDI P N 700 013 Page 4 5 02 01 Connect the 100 ohm resistor to the clip leads and verify the displayed reading is 100 10 ohms If the reading is not within specifications the unit must be returned to the factory for repair 5 02 02 Remove the 100 ohm resistor and connect the 1000 ohm resistor Verify that the displayed reading is 1000 100 ohms If the reading is not within specifications the unit must be returned to the factory for repair 5 03 CHECKING FREQUENCY ACCURACY Set the TT 2D as close as possible to 50 KHz Connect the counter to the XDUCER jack and verify that the displayed reading is within 0 05 0 025 kHz at 50 Khz of that on the frequency counter If the reading is out of spec the unit must be returned to the factory for repair 5 04 SHORT CIRCUIT LOAD CALIBRATION Turn the TT 2D on and store frequency range 3 as the default Set the frequency to 50 Khz Turn TT 2D off Connect the clip leads together to short circuit the output Press and
7. en slide free from the case exposing the battery If possible use 9V alkaline batteries for replacement TT 2 User Manual EDI P N 700 013 Page 5 8 SPECIFICATIONS FREQUENCY RANGE FREQUENCY ACCURACY FREQUENCY RESOLUTION IMPEDANCE RANGE IMPEDANCE ACCURACY TRANSDUCER TYPES BATTERY TYPE CURRENT DRAIN EST BATTERY LIFE RECOMMENDED BATTERY WEIGHT SHIPPING WEIGHT WARRANTY INFORMATION 5 to 500 KHz typically 1 to 550 KHZ 0 05 of indicated frequency 1 digit 0 01 KHz 5 1000 ohm usable 1 9990 ohms 10 of indicated reading All types including transformer coupled Standard 9V transistor radio type 20 mA avg 60 mA max 6 to 8 hours continuous use Alkaline type similar to EVER READY 522 or equivalent 11 ounces with battery and test cable 2 pounds Unit will be repaired free of charge for one year from date of purchase providing there is no water damage or other evidence of improper use or handling Purchaser must ship unit prepaid to address below EDI will pay the return freight Please call before shipping your unit back to us 9 01 TT 2 User Manual Phone For repair ship to Electronic Devices Inc 3140 Bunch Walnuts Road Chesapeake VA 23322 ATTN Service Department 1 757 421 2968 Fax 1 757 421 0518 Please enclose a note describing the problem COMMONLY ASKED QUESTIONS HOW TO SET THE CONTRAST To set the contrast turn the TT 2D off and back on Press butt
8. on A or B while the battery voltage is displayed The contrast setting is stored when the impedance and frequency display appears approximately three seconds after releasing the buttons EDI P N 700 013 Page 6 9 02 9 03 9 04 HOW TO CHANGE THE FREQUENCY RANGE To change the frequency range press button B The range 1 2 or 3 will be displayed while the button is held down When the button is released the TT 2D will operate on that range 9 02 01 The frequency range can be stored so it is selected whenever the TT 2D is turned on To store the range select it as above but do not release button B when the range number is displayed While the range number is displayed press button A then release both buttons The display will momentarily read FR store to indicate the frequency range has been stored to memory HOW TO MEASURE LEAKAGE Press and release button A and the display will read Ohms chk on the top line The resistance will be displayed on the bottom line in exponential format For example a 1 200 ohm resistor will read 1 20E 03 on the bottom line of the display If no leakage is present the display will read gt 5M ohms Allow several seconds to elapse for the reading to stabilize To return to normal operation press and release button B HOW TO DETERMINE IF A TRANSDUCER IS DEFECTIVE A transducer is defective or the wiring is faulty if no resonant points
9. s 4 HOW IT WORKS The TT 2D sends a signal through a 100 ohm resistor to the transducer under test The voltage waveform at the transducer is sampled at three specific points per cycle The relationship of the voltages at the sample points determine the impedance and relative phase of the voltage across the transducer The impedance is calculated and displayed over the range of 1 to 9990 ohms and the relative phase shift is displayed to the right of the impedance reading A plus sign voltage leads current indicates an inductive load and a minus sign voltage lags current indicates a capacitive load The numbers following the polarity sign range from 0 to 30 with the higher numbers indicating a higher reactance 5 CALIBRATION Calibration of the TT 2D should not be necessary unless repairs have been made or internal parts have been changed The calibration is done with the output short circuited The TT 2D is then checked with a 100 ohm and 1000 ohm resistor across the output to see if the displayed readings are within specifications The equipment required to check the TT 2D calibration follows 5 00 01 Frequency counter with 005 or better accuracy 5 00 02 100 ohm 5 resistor 5 00 03 1000 ohm 5 resistor 5 01 CHECKING SHORT CIRCUIT LOAD CALIBRATION Turn the TT 2D on Check the displayed battery voltage It must be greater than 6 5 volts If not replace the battery Set the frequency to 50 KHz and short the output by conne
10. select the range and before releasing button B press button A Release both buttons when the display shows FR store on the bottom line This range will be selected each time the TT 2D is powered up RESONANCE INDICATOR This LED brightens when the frequency approaches the resonant point of the transducer The brighter the LED the lower the impedance is The LED also flashes on power up while the TT 2D initiates the self test routine GETTING STARTED Connect the TT 2D XDUCER output to a transducer Turn the power on and the TT 2D will go through a self test routine while displaying the battery voltage While the TT 2D is in the self test mode the contrast may be set and stored by pressing buttons A or B After the TT 2D displays the frequency on the bottom line select the appropriate frequency range by pressing button B Rotate the coarse frequency control while watching the resonance indicator LED for resonant points There will be three resonance points for most transducers Choose the one that has the brightest indication on the LED Fine tune the frequency with the fine frequency control while watching the display for the lowest Zo indication The phase indication will usually be near zero when the impedance is at a minimum 3 01 3 02 SORTING OUT MULTIPLE RESONANCE POINTS Most all transducers you test will have three major resonance points A major resonance point has a significant peak in the resonance
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