By Dan Collins, Manager of DCS Solution Partner Program, Siemens Energy & Automation It charts the absolute value of the differences between Sensor A and failing Sensor B. Again, sensor Bs oldest 500 values are identical to the first test. Sensor Bs most recent 500 values have been altered by subtracting 20% of the random number to the sensor's value. I.E. Sensor B values for 1 to 500 are 99.5 + random B. Sensor B values from 501 to 1000 are 99.5 + random B - .2 * random B. Notice that a drop in the responsiveness (randomness) of the signals by a mere 20% can be detected. You will notice that the there is at least one alarm (as expected) because the simulated signal noise has diminished to simulate that Sensor B is losing sensitivitybecoming becoming flatlined. Again, notice the sensitivity. The Xbar/R Chart detected drift when the mean difference between the Sensor A values and the Sensor B values closed by a mere 0.012%. In other words, the control chart detected a change in the comparable performance of the two sensors when the noise of one instrument decreased by only 20%. Both instruments are still within calibration, but one is beginning to lose its integrity. If we eliminate 90% of the noise from sensor B, simulating a non-responsive, flatline, comatose instrument, we get the following. See Figure 8. Again, the mean difference has not drifted too far apart but the statistical analysis has recognized the lack of responsiveness. It is now time to calibrate. Sensor reliability and data integrity is assured as long as the pairs of sensors continue to pass the statistical analysis review. When they fail, an alarm generated by the real-time control chart can be triggered through the process control alarm management system. Thus, there is
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3.8 SPICE Simulations
The circuit diagrams, netlist files, and output data associated with SPICE simulations of selected examples are presented in this section. The device models, unless explicitly...
In electronics, a diode is a component that restricts the direction of movement of charge carriers. Essentially, it allows an electric current to flow in one direction, but blocks it in the opposite...
Unless otherwise specified, all electrical parameters in the following problems are as in Examples 5.1 and 5.2.
A simple passive filter has a cutoff frequency...
The Driver Stage
Unless the amplifier is quite low power, it will require a dedicated driver stage. We need a stage with good linearity, low output resistance, and good output voltage swing.
The capacitance across the pair of wires = ( D1 || D2 ) + P0640EC/SC. The diode capacitance is approximately (10 pF || 10 pF ) 20 pF. Then adding the capacitive effect of the P0640EC/SC, which is...