Signal conditioning

Signal conditioning is manipulation of the input measurement to (or output signal from) a controller. A mathematical function is applied in order to improve controller performance. It may be required to compensate for nonlinear behaviour. Alternatively other process parameters may be incorporated into the PV to improve the accuracy of control. 

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Channel AEBIL signal conditioning modules (variable amplifier, RMS measurement, floating threshold level, analog to digital conversion signal) ... 

Signal conditioning. The process of altering the relationship of a transducer (ion or neutral detector) output with respect to time or other parameters (frequency, voltage, or current). 

Displacement, or eddy-current, probes are designed to measure the actual movement, or displacement, of a machine s shaft relative to the probe. Data are normally recorded as peak-to-peak in mils, or thousandths of an inch. This value represents the maximum deflection or displacement from the true centerline of a machine s shaft. Such a device must be rigidly mounted to a stationary stmcture to obtain accurate, repeatable data. See Figure 43.21 for an illustration of a displacement probe and signal conditioning system. 

Figure 43.21 Displacement probe and signal conditioning system...

Most infrared monitoring systems or instruments provide special filters that can be used to avoid the negative effects of atmospheric attenuation of infrared data. However the plant user must recognize the specific factors that will affect the accuracy of the infrared data and apply the correct filters or other signal conditioning required negating that specific attenuating factor or factors. 

Intelligent transmitters have two major components (1) a sensor module which comprises the process connections and sensor assembly, and (2) a two-compartment electronics housing with a terminal block and an electronics module that contains signal conditioning circuits and a microprocessor. Figure 6.9 illustrates how the primary output signal is compensated for errors caused in pressure-sensor temperature. An internal sensor measures the temperature of the pressure sensor. This measurement is fed into the microprocessor where the primary measurement signal is appropriately corrected. This temperature measurement is also transmitted to receivers over the communications network. 

The sensors are also classified according to the major technologies used in their production. Technologies that allow large-scale production of reliable sensors at low cost are becoming particularly important The compatibility of such sensors with electronic signal conditioning is an additional bonus. 

Cheap, very sensitive pressure sensors will be used to monitor the behavior of ventilation systems. These will be based on silicon sensors with built-in signal conditioning. 

It also avoids rectification errors (no-symmetrical clipping) in signal conditioning electronics. 

For time t > % this current is zero because the carrier would have reached the substrate. The current I(t) can be detected via the voltage it induces in the external circuit. Shortly, the equivalent electrical circuit of the XTOF experiment under the small-signal condition contains the coupling capacitance Cl (the sum of the amplifier and the parasitic capacitances) and f L ( l is the load resistance). The total current is the sum of the conduction current due to the drift of photogenerated charge and the displacement current and is equal to zero (for further details, see Ref [15]),... 

Electroded TOF experiments have already been described previously [29]. They were carried out under small-signal conditions to determine hole and electron drift mobility. Carriers were generated by illuminating the sample through the... 

Signals, signal conditions, and the direction of evolution. American Naturalist 139(suppl.) S125—S153. 

The input/output units of the programmable controller constitute the interface between the PLC and the outside world. Hence, they are provided with the necessary signal conditioning functions which enable the PLC to be connected directly to the process actuators and transducers as desired. For this purpose the... 

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