Vishay 2310 Guia do Utilizador descarregar pdf (Página 18)

In the case of the current set-up, the range can be set to 5V. Thus, the resolution is

0.22mV. Amplifier gain determines the transfer function between signal voltage and represented

strain. When gain is 200, the resolution represents 0.23 microstrain.

In order to enable successful implementation of the laboratories, suitable signal

conditioners should satisfy a series of requirements. Both laboratories uses strain gauges with

120Ω resistance, the signal conditioner should be able to provide quiet, accurate and stable

readings with selected strain gauges. The laboratories currently use a gain setting close to 200;

the signal conditioner should be able to offer a comparable gain. The vibration measurement

laboratory requires the signal conditioner to have a frequency response of over 1kHz. Gain

indication and bridge balancing are preferred, optional internal Wheatstone bride completion

circuit is another preferred feature. The cost for each unit of signal conditioner should be

relatively low, so that experiments involving multiple channels of strain measurement could be

developed in the future.

The currently deployed signal conditioner is Vishay 2310 Signal Conditioning Amplifier

System (Vishay 2310). Extensive search of available commercial products was conducted to

select the potential alternative systems that satisfy most criteria listed above.

3.1.2 In-Lab Output Testing

In-lab testing of the signal conditioners’ output is conducted. A quarter bridge completion

board is used for testing of all signal conditioners except Vishay 2310, which contains an internal

quarter bridge completion circuit. The variable strain gauge is installed on an aluminum

cantilever beam with one foot of gauge 26 wires. For Omega, the gain was adjusted so that 1V

signal output corresponds to 800 microstrain. Table 1 shows the excitation and gain selected for

each signal conditioner for this testing. The signal conditioners require time to “warm up”, so

that optimum performance can be achieved. Table 1 shows the warm-up time used for each

signal conditioner during testing.

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Vishay 2310 Guia do Utilizador Página 18