P-3500 Vishay Measurements Portable Strain Indicator

The Vishay Measurements Model P-3500 Portable Strain Indicator is a portable, battery-powered instrument with unique features for use in stress analysis testing and for use with strain gauge based transducers. The P-3500 offers a choice of LCD or LED readouts and incorporates many unique operating features that make it the most advanced and easy-to-use instrument of its kind. In use, the operator follows a logical sequence of setup steps by activating color-coded push-button controls to prepare the instrument for making accurate and reliable measurements. The P-3500 also incorporates a highly stable DC amplifier, precisely regulated bridge excitation supply and precisely settable gauge factor controls.

Static measurements are displayed directly on the indicator's readout with 1 microstrain resolution. An analog output with a -3 dB bandwidth of 4 kHz is provided to drive an external oscilloscope or recorder for dynamic measurements. The instrument will accept full-, half-, or quarter-bridge strain gauge inputs and all required bridge completion components for 120, 350 and 1,000 Ohm gauges are built-in. Bridge excitation is 2 Vdc, resulting in low gauge power and negligible drift due to gauge self-heating. The P-3500 operates in fully ratiometric mode. Minute changes in bridge excitation due to drift or battery deterioration do not affect accuracy of reading. Gauge factor is precisely settable (to a resolution of 0.001) by a front-panel 10-turn potentiometer and is displayed on the digital readout when the gauge factor push button is depressed.

The P-3500 operates from an internal battery pack consisting of 6 "D" cells, which are readily available worldwide when replacement is required. Battery life is approximately 250 to 300 hours of continuous use (approx. 200 hours with LED readout). Battery condition is monitored by a miniature front-panel meter while the instrument is on. An external line- voltage adapter is also available (115 or 230 Vac, 50 to 60 Hz). An optional transducer input connector facilitates connection of four- or six-wire strain gauge based transducers. The P-3500's unique remote-sense feature is operational whenever the remote-sense leads are connected and no switching is required. A remote calibration resistor is also accessible via a contact closure at the transducer connector.