ENDEVCO 2680 Series Скачать руководство пользователя страница 6

ENDEVCO 2680 

INSTRUCTION MANUAL

 

 

IM2680 

Page 1-2 

must be sealed to the case with solder, glyptol or epoxy for the Charge Amplifier to meet humidity 

specifications during operation. 

 

 

Charge Amplifiers shipped as single items of equipment have the Gain Potentiometer set to the 

maximum rated gain of the Charge Amplifier, and the Gain-Access Screw temporarily seated in 

the threaded access hole.  Users of the Charge Amplifier are then required to adjust the gain to a 

desired gain setting prior to application of a Charge Amplifier (see Paragraph 4.2).  Table 1-2 lists 

the gain ranges for each "M" series (M1 thru M7, M12 and M14) of Charge Amplifiers. 

 

____________________________________________________________________________ 

 

___Power Requirements____ 

 

 

Current 

Basic  Input 

Output 

DC-to-DC  Voltage  M1-M7  M12, M14 

Model  Connector 

Connector 

Accessories 

Conv. 

VDC 

mA DC  mA DC  _   

 

2680 

Microdot 51-49  Viking VR5/4AG15 

Endevco Kit 21997 consisting of: 

No 

20-32 V 

< 20 

< 25 

 

10-32 

Endevco P/N EP30    Mating Plug - Viking VP5/4CE6 

 

28 V typ 

 

 

UNF-2A thread  5-Pin connector 

  Hood - Viking VS4/16C5 

 

 

 

  Potting Sleeve-VikingVS4/16C9 

 

 

 

Mounting Hardware - Two #6-32 

 

 

 

  Captive Screws w/ Lockwashers 

 

2681 

Microdot 51-49  Viking VR7/4AG15 

Endevco Kit 23318 consisting of: 

Yes 

24-32 V 

< 30 

< 35 

 

10-32 

Endevco P/N EJ277    Mating Plug - Viking VP7/4CE6 

 

28 V typ 

 

 

UNF-2A thread  7-Pin connector 

  Hood - Viking VS4/16C5 

 

 

 

  Potting Sleeve-VikingVS4/16C9 

 

 

 

Mounting Hardware - Two #6-32 

 

 

 

  Captive Screws w/ Lockwashers 

 

2680 

Microdot 51-49  Viking VR7/4AG15 

Endevco Kit 21997 consisting of: 

Yes 

20-32 V 

< 30 

< 35 

 

10-32 

Endevco P/N EJ277    Mating Plug - Viking VP5/4CE6 

 

28 V typ 

 

 

UNF-2A thread  7-Pin connector 

  Hood - Viking VS4/16C5 

 

 

 

  Potting Sleeve-VikingVS4/16C9 

 

 

 

Mounting Hardware - Two #6-32 

 

 

 

  Captive Screws w/ Lockwashers 

______________________________________________________________________________________________________ 

 

 

TABLE 1-1:  CONNECTORS, ACCESSORIES, AND POWER REQUIREMENT

 

 

3. 

OUTPUTS 

 

 

Each Charge Amplifier has two outputs, biased and/or unbiased.  The outputs can be a 

combination of a biased and an unbiased, or both outputs can be biased, or both outputs can be 

unbiased.  The "M" number following the model number is the determinant (see "Types of Output" 

column in Table 1-2).  Both outputs are single-ended with one side connected to circuit ground.  

When both outputs for the M1 through M7 are used simultaneously, the parallel combination of 

both load resistances must be 10 k

 or greater to meet all specifications.  For the M12 and M14, 

both outputs can be loaded with 10 k ohms or greater simultaneously and still meet all 

specifications.  Maximum output voltage is approximately 0 to 5 v (±2.5 v pk) depending on the 

specific Charge Amplifier.  The output  circuits are short-circuit proof, thus the outputs will 

withstand an indefinite short without damage. 

 

 

The    biased  outputs  are  direct  coupled  with  an  output  impedance  of  less  than  50  Ω.    With  no 

input, the Charge Amplifier pr2.5 V dc 

±

3%  at  the  output.    Output  voltage  will  be 

approximately ±2.5 V pk around this bias level.  Clipping will occur slightly about the 0 V level and 

b5.0 and +5.3 V. The unbiased outputs are in series with a minimum 16 uF capacitance 

and have an output impedance o

f less than 50 Ω.  With the addition of the series capacitor and 

bleed resistor in the output, a 0.00 V bias level is established.  The unbiased output is linear from 

0 to 4.65 V p-p, or 0 to 5.00 V p-p, depending on the specific Charge Amplifier used. 

 

 

Refer to Table 1-2  for further output data on specific "M" series Charge Amplifiers. 

Содержание 2680 Series

Страница 1: ...IM2680 Revision B Nov 1 91 MODEL 2680M1 M7 2680M12 M14 2680M61 67 2681M1 M7 2685M1 M7 AIRBORNE CHARGE AMPLIFIER INSTRUCTION MANUAL ...

Страница 2: ...IM2680 Revision B Nov 1 91 San Juan Capistrano Calif ornia U S A ...

Страница 3: ...PECTION 2 1 2 INSTALLATION 2 1 SECTION 3 PRE OPERATION TEST 1 INTRODUCTION 3 1 2 EQUIPMENT REQUIRED 3 1 3 VOLTAGE INSERTION TEST PROCEDURE 3 2 4 ALTERNATE TEST METHOD 3 3 SECTION 4 OPERATIONAL CHECKOUT PROCEDURE 1 USING THE CHARGE AMPLIFIER 4 1 2 GAIN ADJUSTMENT 4 1 3 AMPLITUDE LINEARITY 4 2 4 FREQUENCY RESPONSE 4 3 5 DC TO DC CONVERTER 4 3 APPENDIX A THEORY OF OPERATION 1 INTRODUCTION A 1 2 CHARG...

Страница 4: ...ON TEST SETUP 3 2 3 2 ALTERNATE CHARGE INSERTION TEST SETUP 3 3 4 1A TYPICAL SYSTEM CONNECTIONS WITH CHARGE AMPLIFIER 4 2 4 1B TYPICAL SYSTEM CONNECTIONS WITH ISOTRON CONDITIONER 4 2 A 1 PIEZOELECTRIC TRANSDUCER EQUIVALENT CIRCUIT A 1 A 2 BASIC AIRBORNE CHARGE AMPLIFIER FUNCTIONAL BLOCK DIAGRAM A 3 A 3 TYPICAL SYSTEM EQUIVALENT CIRCUIT A 4 B 1 TYPICAL GAIN CALIBRATION TEST SETUP B 2 B 2 GAIN ADJUS...

Страница 5: ...verter 2685 Endevco Connector DC to DC Converter Integral Electronic Conditioner with constant current supply Each basic model consists of a series of modifications M series to provide seven different gain ranges and nine different high frequency responses The M series covered by this Instruction Manual are M1 thru M7 M12 and M14 Table 1 2 lists the M series and provides a comparison of their inpu...

Страница 6: ...Potting Sleeve VikingVS4 16C9 Mounting Hardware Two 6 32 Captive Screws w Lockwashers ______________________________________________________________________________________________________ TABLE 1 1 CONNECTORS ACCESSORIES AND POWER REQUIREMENT 3 OUTPUTS Each Charge Amplifier has two outputs biased and or unbiased The outputs can be a combination of a biased and an unbiased or both outputs can be b...

Страница 7: ... Vp p 4 25 Vp p 4 65 Vp p 0 465 mA p p Unbiased 1 64 Vrms 1 5 Vrms 1 64 Vrms 0 164 mA rms M 7 500 10 to 100 2 0 Biased 2 5 V 0 00 V 4 65 Vp p 4 25 Vp p 4 65 Vp p 0 465 mA p p Unbiased 1 64 Vrms 1 5 Vrms 1 64 Vrms 0 164 mA rms M12 Low 5 000 1 0 to 10 1 5 Biased 2 5 V 0 00 V 4 65 Vp p 0 465 mA p p Gain 1 64 Vrms 0 164 mA rms High 5 000 10 to 100 7 5 Biased 2 5 V 0 00 V 4 65 Vp p 0 465 mA p p Gain 1 ...

Страница 8: ... Accelerometers Microphones Force Gages or Pressure Pickups The small size light weight low power consumption and the use of long cables to connect Transducers to the Charge Amplifier enables the unit to be used in ground and laboratory testing rocket test stands combined environmental testing steam turbines and other industrial applications ________________________________________________________...

Страница 9: ...ies listed in Table 1 1 are included in the shipment with each Charge Amplifier 2 INSTALLATION The Charge Amplifier case is drilled with two holes for mounting the unit to the test specimen The mounting holes vary in size and placement for each Charge Amplifier thus the user should refer to the appropriate Product Data Sheet or Performance Specification for an outline drawing depicting the mountin...

Страница 10: ...ge must be established The output voltage established must be less than the Charge Amplifier s full scale output maximum 5 V p p or 1 77 V rms As an example the 2680M1 has a maximum linear biased output of 4 65 V p p 1 64 V rms into a 10 000 ohm load Thus the output established for a 2680M1 should be less than 4 64 V p p Normally an output voltage is selected which is easily read on the readout de...

Страница 11: ...ometer and Cable Assembly Calibration Cards for capacitance of each item Use the following formula to determine total capacitance Cin seen at Charge Amplifier s input Cin Cp Cc where Cp Internal Capacitance of Accelerometer Cc Cable Capacitance between Accelerometer and T Block D Establish an Output Voltage Eo for Charge Amplifier The Output Voltage should be less than the maximum linear output fo...

Страница 12: ...or s output to Ein and applying this voltage to the input of the T Block H Since both an input Ein and output Eo has been established and verified the Voltage Insertion Test can now be used to verify system integrity anytime the system is suspected of being faulty or assurance that the system is performing to specification I Set switch S1 to OPR operate position and S2 to OUT position for normal s...

Страница 13: ...ximum Linear Output for the applicable Charge Amplifier E Again the formula for input versus output is Eo x 103 Ein Aq x Cin where Eo Output Voltage in volts Ein Input Voltage to T Block form Oscillator in volts Aq Charge Amplifier Gain in mV pC see paragraph 4 2 Cin Input Capacitance in pF Includes Accelerometer Capacitance Cp and Cable Capacitance Cc between Accel and T Block F Repeat steps 3 3 ...

Страница 14: ...e with the input The 1 10 mV pC low gain outputs of the M12 and M14 are in phase with the input signal while the 10 100 mV pC high gain outputs of the M12 and M14 are 180 out of phase with the input 2 GAIN ADJUSTMENT Each Charge Amplifier provides two outputs and Gain Potentiometer is common to both outputs Those Charge Amplifiers M12 and M14 with dual biased or dual unbiased outputs have a 10 1 r...

Страница 15: ...rgize equipment and allow 15 minutes to temperature stabilize C Adjust power supply for 28 V dc output D Set Voltage Divider Potentiometer to its maximum output fully CW E Adjust Oscillator Frequency for 100 Hz and set test setup switch S1 to OUT position and then adjust Oscillator Output Amplitude until Charge Amplifier s output is 100 mV below clip level on Oscilloscope note DVM for mV rms indic...

Страница 16: ... setup switch S1 to 1N position Verify Oscillator Output Amplitude is still 1 0 V rms and then set switch to OUT position NOTE A Charge Amplifier s frequency range of interest depends on type of filter used Refer to Table 1 3 for Model versus Frequency Range I Vary Oscillator Frequency over Charge Amplifier s range of interest and observe Oscilloscope and DVM for Gain versus Frequency Response The...

Страница 17: ...ALENT CIRCUIT A simplified equivalent circuit of a Piezoelectric or Capacitive Transducer is shown in Figure A 1 The open circuit voltage Eo is equal to the charge q divided by the Transducer Capacitance Cp as noted in the following formula Eo q Cp where Eo is expressed in V q is expressed in pC Cp is expressed in pF If the Open Circuit Voltage is known the Transducer charge can be calculated by q...

Страница 18: ...ucer no additional calculations are necessary For example the typical voltage sensitivity Ecal of the Endevco Model 2272 Accelerometer is 4 0 mV g typical capacitance is 2700 pF and the Accelerometer is calibrated with 300 pF of external capacitance Thus the typical Charge Sensitivity is Qs 4 2700 300 1000 12 pC g 2 CHARGE CONVERTER A functional block diagram of a basic Airborne Charge Amplifier i...

Страница 19: ...ain Range The Gain is externally adjusted after removal of an Access Screw Both the Charge Converter and Voltage Amplifier Gains are fixed for optimum stability 4 VOLTAGE AMPLIFIER The final stage of the Charge Amplifier is a Voltage Amplifier Because of its low output impedance and 0 5 mA minimum output current the Charge Amplifier is capable of driving tape recorders directly The outputs are bot...

Страница 20: ...t shown Cp is the Transducer Capacitance Cf is the total external shunt cable capacitance and Cp Cf is the total source capacitance for the Charge Amplifier FIGURE A 3 TYPICAL SYSTEM EQUIVALENT CIRCUIT The Charge Gain in mV pC of the system is defined by the formula Eo Aq _____ q in where Aq Charge Gain of Charge Amplifier in mV pC Eo Charge Amplifier output in mV qin Charge Amplifier input Transd...

Страница 21: ...ut in mV pk FS Charge amplifier s desired peak full scale output in g pk The Amplifier s Charge Gain Setting Aq is computed by As Aq ______ Sq where Aq Amplifier s Charge Gain setting in mV pC Sq Transducer s Charge Sensitivity in pC g As an example suppose a system consisting of an Endevco Model 2680 Series Charge Amplifier which has a 2 5 V pk or 2500 mV pk full scale output and an Endevco Model...

Страница 22: ...ibration Figure B 1 is a typical test setup used for Gain Calibration FIGURE B 1 TYPICAL CALIBRATION TEST SETUP To charge applied to the input of Charge Amplifier in Figure B 1 is determined by qcal Ecal Ccal where Ecal Oscillator output in V Ccal Series calibration capacitor in pF qcal Charge applied to the Charge Amplifier in pC The Charge Gain of the Amplifier Aq is determined by Eout As Aq ___...

Страница 23: ...arge Amplifiers Access Screws can be procured from Endevco under part number 1103 see Table B 1 Table B 1 lists the equipment required to remove and seal the Gain Access Screw and to adjust the Gain of the Charge Amplifier as defined ________________________________________________________________________ ITEM PURPOSE ________________________________________________________________________ Power s...

Страница 24: ...rom entering Charge Amplifier interior E Apply torque CW to Allen wrench and remove the access screw when the solder seal is molten 5 SEALING ACCESS SCREWS New Access Screws should always be used to seal the gain adjust hold Installing used Access Screws could prevent the Charge Amplifier from meeting humidity specifications A Install a new Access Screw in gain adjust hold B Preheat oven to a temp...

Страница 25: ...ENDEVCO 2680 INSTRUCTION MANUAL IM2680 Page B 5 FIGURE B 2 GAIN ADJUSTMENT FOR CHARGE AMPLIFIERS WITHOUT DC TO DC CONVERTERS FIGURE B 3 GAIN ADJUSTMENT FOR CHARGE AMPLIFIERS WITH DC TO DC CONVERTERS ...

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