Model 311A is an intrinsic safety IEPE accelerometer permitting vibration measurements. 311A features an annular shear ceramic crystal which exhibits excellent output stability over time. The accelerometer incorporates an internal circuit with in a two-wire IEPE system which transmits its low impedance voltage output through the same cable that supplies the constant current power. Signal ground is internal shielded and isolated from the outer case of the unit. Polarity inversion protection for the amplify circuit is inherent in the circuit design. The welded stainless-steel construction provides a hermetic housing. The standard MIL-C-5015 glass insulated connector provides long-term stability over the operating temperature range. In addition to adhesive mounting, 311A has ¼-28 threaded holes for stud mounting on the test object. The 311A provides wide frequency response and shock resistance, which is ideal for industrial vibration monitoring under incidental shock environment. Senther’s model 16-L is a MIL-C-5015 connector mating cable for the sensor.