Dynamic Distributors 103B11 manual MICROPHONE3 Series 103A, Maintenance and Repair, Output Signal

OPERATION MANUAL FOR

MICROPHONE3 Series 103A

Refer to Guide G-0001B for tips on power and signal utilization.

NOTE: The internal low-noise amplifier in the Model 103A, A02, A11 and A12 differ from the standard ICP® amplifiers described in Guide G- 0001B in that the turn-on (or bias) voltage is nominally +4 volts.

Proper turn-on for Models 103A02, A11 and Al 2 will not give center scale reading on the fault monitor meters found on most PCB signal conditioners but will show a reading of approximately 20% of F.S. on these meters. This puts it at the lower limit of the green (or normal) area of the meters. This is normal and in no way indicates faulty operation.

At PCB, the units are subjected to various calibrated steps of pneumatic pressure to obtain a linearity curve over the full range of the instruments.

6.0MAINTENANCE AND REPAIR

The small size and sealed construction of the Series 103A precludes field maintenance and repair.

Should the time constant degrade or an abnormality appear in the normal bias voltage, bake the unit out in a +250° F oven for 1 to 2 hours, then re-test.

If this is not effective or if other problems should occur, contact the factory for assistance in tracing the problem or for instructions on returning the unit for repair.

4.0OUTPUT SIGNAL

The output signal from the 103A Series is a voltage proportional to input pressure. The polarity is positive-going for increasing input pressure.

The signal is of high enough level and low enough output impedance to be fed directly into most oscilloscopes, tape recorders, strip chart recorders, A to D converters, etc.

Consult the factory for information regarding galvo driving since special amplifiers are needed to drive most high-current galvanometers.

Low-frequency response is limited by sensor discharge TC (given in the specification sheet) and by coupling time constants throughout the system. To take full advantage of the TC of the sensor, make sure that coupling TC's from power unit to readout are at least an order of magnitude longer than the discharge TC or use a direct-coupled signal conditioner such as the Model 484B. Consult factory for details.

5.0CALIBRATION

The 103A Series Sensors must be dynamically calibrated using a known step function or pulse, or with a microphone calibrator.

Drawing Number: 21082

Revision: NR

7.0PRECAUTIONS

l.) Do not apply voltage to the unit without a current-limiting device in the line such as incorporated in all PCB signal conditioners, (20 mA maximum) to do so will destroy the internal amplifier.

2.) Do not subject these units to temperatures higher than 250° F.

3.) Do not attempt to disassemble these units as to do so voids the warranty.

4.) Use caution when removing units that have been mounted with epoxies or other strong adhesives. Excessive squeezing or torquing may damage the units and/or cause a calibration shift.

5.) In vibratory environments, secure cables and leads to surrounding structures to avoid lead or cable damage.

6.) Do not over torque when using the Servo clamps or the clamp nut since this could damage the units.

7.) Do not overpressure (see specs for maximum pressure), to do so may change the calibration.

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