The new Program and Control System(PCS) is a two computer master-servant system that provides autonomous (master independent) data acquisition, test sequence and temperature control. Multiple crystal-controlled timing without dependence on the master or servant CPU clocks provides superior dynamic data acquisition and loss factor resolution. Test setups are user friendly with an all-new graphical user interface. Online monitoring using either a virtual storage/scanning oscilloscope or XY oscilloscope function provides for verifying signal integrity and for new sample setup. Both oscilloscope functions provide a complete set of controls and include auto-time base selection and an auto-zero suppression feature that enables the viewing of small dynamic signals in the presence of large static signals.

Data acquisition is provided by two independent analog to digital boards with high resolution and auto-gain features. For transient testing, an 18 bit integrating type A to D is used for accurate load and displacement measurements and superior signal to noise ratios. Dynamic data acquisition is via a 16 bit sample and hold A to D with 10 microsecond data cycle, in addition to an auto-gain feature prior to the A TO D conversion for each channel (load and displacement) that provides gains of x1 to x128 in powers of two. This feature allows a wide range of dynamic signal amplitudes to be sampled without loss of digital resolution. A proprietary DC signal rejection feature allows the full dynamic gain of x128 to be used in the presence of large static signal components. Thus, it is possible to recover a 40 mv dynamic signal in the presence of a full-scale static signal of 10 volts without digital saturation and with full 16-bit resolution. This feature is particularly useful when testing soft materials such as elastomers where the sample is subjected to a large static load or displacement offset while conducting dynamic tests. Crystal-controlled A to D data acquisition with fully buffered data storage provides exceptional phase angle integrity at all frequencies, with no dependence on the CPU clock or interrupt timing.

Dynamic signal generation is by a 16 bit D to A with 1024 words per period for a sine wave and no loss in resolution of the sine wave with amplitude. Constant rate ramp signal generation also uses 1024 words per ramp for exceptional linearity. A new Fast Fourier Transform algorithm is used for dynamic data analysis and provides exceptional noise rejection, high resolution and accurate measurements of the modulus and loss factor.

Transient test data is obtainable at 5 or 10 points per decade of time and is logarithmically spaced. Dynamic data is obtained at 10 points per frequency decade, also logarithmically spaced. A full sweep involving 31 data points from 0.1 to 100 Hz and final results of modulus and loss factor takes less than 7 minutes and includes automatic settling time and auto-gain for each data channel at each frequency. The user can also elect to perform a single frequency measurement for each temperature in the test sequence.

Temperature test sequence can involve either constant spacing of the temperature jumps, or a completely arbitrary sequence of temperatures chosen by the operator.

The PCS provides algorithms for a variety of specimen geometries including tension and compression of right circular cylinders or rectangular samples, three point bending, centro-symmetric deformation, and shear samples. Data can be viewed conveniently by the use of Quick Graph routines that present the data with a single mouse click in either scientific or British units of measure. Master curve generation and time (or frequency) superposition is readily accomplished using the automatic shifting algorithms. Fully scaled results in the desired units can be output directly to a spreadsheet file compatible with Microsoft's Excel.