Sequential control

The system PLC handles the sequential control of the system, while the actual manipulation of the fish block in the X-ray beam is done by joystick from the operators control station. 

This control activity includes process control and unit management. Process control includes those loops and devices that perform sequential control, regulatory control, and discrete control. Unit management is responsible for coordinating the activities associated with the batch units (e.g., allocating resources within the unit, ensuring that batch sequences proceed in the proper order, etc.). 

Any other similar condition, interlocking with other feeders or sequential controls etc. 

Sequential control for vessel sterilisation and more complex control strategies... 

Interlock and sequential control logic is performed by mechanical/electric relays and timers and the production train shutdown is performed by a combination of mechanical/electric relays and pneumatic relays. 

Schneider and Oliver s approach exhibits several innovations. One is the decomposition of complex tasks, which facilitates sequential controlled processing. The end result is performance in a reasonable time frame. Most connectionist models take unreasonably long to learn simple patterns. The Schneider and Oliver model works very quickly. A second innovation is the generation and use of rules to operate on the data networks. Thus, learning occurs in two ways in this model, by back propagation following multiple presentations of stimuli and by direct instruction from the controller network. 

The task net after migration is shown in Fig. 3.80. The control flow from the estimation task to the flowsheet design task is marked as behaviorally inconsistent (emphasized by red color). Both tasks are currently active, while the revised process definition prescribes a sequential control flow. This illustrates that migration does not necessarily result in a task net which does not contain inconsistencies. Migration can always be performed - even if inconsistencies persist. 

In a projected paper, a comprehensive discussion of the nature and role of what we tentatively define as sequential control sites on receptor surfaces (and some regulatory enzymes) will be presented. We shall here be concerned only with those general aspects which are especially relevant to the problem of structure-activity relationships among drugs. 

Well-developed sequential control sites, where conformational changes can be induced, should be especially prevalent among receptor surfaces for neurotransmitters in view of the rapidity with which interneuronal communications must be established in the CNS as an example. 

For the neurotransmitter norepinephrine, symmetry considerations similar to those applied above to the succinyldicholine binding sites allow the prediction that quasi-symmetrically disposed binding areas for aromatic rings may be present on the receptor surface (Figure 7), and if the conformational and electronic properties of the drug are compatible with the detailed topography, unproductive physical states may be readily induced in the receptor. The sequential control areas being quasi-symmetrically disposed, the basis of an explanation for the well-established... 

Ratio control (Figure 2.8-17b) is often used in controlling constant mixing ratios (e.g., stoichiometric feeding of two starting materials A and B). The value of flow A is input via a ratio controller as the setpoint for the sequential controller (flow B). 

Fig. 7. Sequential control of the synthesis of the aspartate family of amino adds. Temporal control of the flow of carbon is illustrated by the successive Figs. 1-5. Potential quantitative changes in flow are approximated by the thickness of the solid arrows. As the concentration of an end product is increased (indicated by closed boxes), the pattern of synthesis is altered by utilization of negative (-) or positive (+) regulatory mechanisms as described in the text. The pattern of control which is illustrated assumes that aspartate kinase is sensitive to inhibition only by lysine. Variations of this pattern are discussed in the text.

Fig. 8. Sequential control of branched-chain amino acid synthesis. Changes in the flow of carbon are approximated by the thickness of the solid arrows. These are facilitated by the specific regulatory mechanisms indicated by dashed arrows and by other factors which are discussed in the text.

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