Electronic instrumentation is behind the accurate, stable measurements that control processes in large industrial plants. However, there are a variety of environmental and application-related factors that impact stability, from fluctuating temperatures and humidity to harsh manufacturing conditions and elapsed time.
Performance decline in sensors or instruments is known as drift. When drift occurs, measurement data from the sensor becomes unreliable and can impact the quality of factory production. Calibration helps identify and resolve drift, but this process can be costly and also lead to factory downtime.
It is, fortunately, possible to tailor a calibration strategy by better understanding and minimizing drift behavior in voltage references. After all, sensors and instruments are only as accurate as their references.
Large industrial plants rely on electronic instrumentation to control their manufacturing processes
Long-term stability is the parameter that quantifies drift in voltage references. Defined as a slow change in output voltage, generally in one direction over months of operation, long-term stability is expressed in ppm/1000 hours. In fact, because of the implications related to voltage reference drift, semiconductor manufacturers are encouraged to go beyond 1000 hours of test time to ensure accurate, reliable operation. Such tests are typically performed on a selected sample population under set conditions for nominal input voltage, temperature, humidity, and load.
Read my Design Solution, Voltage Reference Long-Term Stability Reduces Industrial Process Control Calibration Costs, for details on a test case that demonstrates extended long-term stability testing for the MAX6126 ultra-high-precision, ultra-low-noise voltage reference. This particular voltage reference has a long-term stability of 20ppm/1000 hr (typ). In the Design Solution, you’ll learn how increasing long-term stability test time can help instrumentation and process control designers minimize the need for calibration and downtime.