Signal conditioner controls signal to noise ratio

Edited by the Engineeringtalk editorial team Feb 12, 2008

The 6037's "smart" gain ranging can reduce gain or increase it when the signal is below a specified threshold.

Pacific Instruments has released an eight-channel strain gauge and transducer signal conditioning amplifier/digitiser for its series 6000 data acquisition system.

The Model 6037 automatically ranges gain according to signal level for the optimum signal to noise performance.

It is designed for large strain gauge applications such as airframe structural testing.

Selecting the channel gains to use on a large structural test is a time consuming task.

Under or overestimating signal levels results in lost or degraded data.

Users always want the highest gain possible, which results in the best signal-to-noise performance.

If the signal level is higher than expected, however, it will overscale the amplifier, resulting in lost data.

Too low a signal results in degraded resolution and poor signal-to-noise performance.

Automatic gain ranging eliminates these concerns by dynamically scaling the amplifier's gain to the input signal level, providing the highest output without overscale.

Recent advances in logic array technology and density make it possible to provide "smart" automatic gain ranging.

Simple gain ranging has been feasible for some time.

The 6037's "smart" gain ranging can reduce gain or increase it when the signal is below a specified threshold.

Furthermore, the user can program the signal levels at which to reduce or increase gain for each channel independently and can program a period of time which the signal must be above or below the threshold before the gain change takes place.

This last feature prevents gain ranging on noise or transients.

Gain codes for the eight channels on each 6037 are output on two 16bit "phantom" channels.

By including the "phantom" channels in the series 6000 scan table, the gain employed for each data sample is known.

PI660 software automatically accounts for gain ranging in displayed and exported data.

The 6037 is entirely programmable.

Software configures it for quarter, half or full bridge transducer eliminating the usual jumpers, soldering and need for precision bridge completion resistors.

Excitation is programmed in 1V steps from 0 to 12V Automatic zero and balance replace the tedious manual adjustments usually associated with strain gauges and bridge transducers.

If automatic gain is not employed, it is programmable from 1 to 5000 with 0.05% accuracy.

A four-pole, low-pass filter provides bandwidths from 1Hz to 1kHz with programmable selection of filtered or wideband output.

End-to-end voltage calibration using a certified standard provides NIST traceable measurement accuracy.

A 16bit ADC digitises the transducer signals at programmable sample rates up to 10K per channel.

Individual sample and hold amplifiers provide 50ns time correlation channel to channel.

In addition to the digitised output, each channel has a high-level output for analogue monitoring and recording.

Two sets of programmed high and low alarm levels are monitored for each channel.

An alarm may be used to automatically activate digital outputs that can control external equipment or provide operator warning.

Hardware-based alarms provide the fastest means of detecting conditions that could damage an expensive test article.

A 14in-high, rack-mounting enclosure holds up to 128 channels and, with additional enclosures, a system can be expanded to 4096 channels.

It is available with IEEE-488, Ethernet or USB 2.0 interface for programming and data output.

PI660 Software for Windows supports the 6037 for setup, control and data recording, distribution and display.

An application programmers interface (API) is available for programming custom application software in Visual Basic, LabView, Excel and other languages that support DLL calls.