DJB Instruments

Instrumentation - V4/04

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O/P Normalises 1V/g or 0.1V/g, for I/P's 10, 31.6 or 100mV/g • 28V 4mA Transducer Supply, Transducer O/C & S/C Fault Detection • O/L Indicator, DC O/P

The V4/04 is a four channel QVC interface amplifier, providing a low cost, space efficient solution to multi channel piezo-tronic transducer interfacing at the expense of somewhat reduced flexibility. Each channel provides switched normalised outputs of 1 or 10g/V for transducer sensitivities of 10, 31.6, or 100mV/g. Gain is thus adjustable over the range x1 to x100 in 10dB increments.

This is a much reduced dynamic range compared to that of the VV/04, but suffices for a very broad range of applications, particularly where close tolerance transducers equating to the three normalising options are used.

Each V4/04 amplifier channel includes an integral 28V 4mA transducer power source, transducer O/C and S/C fault detection LEDs, an output overload indicator LED, and AC/DC peak converter output.

Transducer Power Supply

Input is assumed to be a two wire active device (QVC) with the signal offset by a DC bias which is the de facto QVC operating voltage Vb. Vb is temperature dependent. Signal excursion should not be constrained by virtue of power supply (voltage, current drive capability) limitations.

The O/P overload detector comprises a linear absolute value peak detector, comparator and LED. The peak detector provides the ancillary DC O/P. Note that the peak detector’s 5sec.time constant is conditional upon minimal loading, a 10MΩ load will halve the t/c.

The V4/04 allows 24 channels of QVC interface to be packed into a single housing.

Benefits are a reduction of up to 65% in capital cost and 50% space saving.



V304 schem




V404 Table