Multiple operator controls

Ratio and Multiplicative Feedforward Control. In many physical and chemical processes and portions thereof, it is important to maintain a desired ratio between certain input (independent) variables in order to control certain output (dependent) variables (1,3,6). For example, it is important to maintain the ratio of reactants in certain chemical reactors to control conversion and selectivity the ratio of energy input to material input in a distillation column to control separation the ratio of energy input to material flow in a process heater to control the outlet temperature the fuel—air ratio to ensure proper combustion in a furnace and the ratio of blending components in a blending process. Indeed, the value of maintaining the ratio of independent variables in order more easily to control an output variable occurs in virtually every class of unit operation. 

Selective and Override Control When there are more controlled variables than manipulated variables, a common solution to this problem is to use a selector to choose the appropriate process variable from among a number of available measurements. Selec tors can be based on either multiple measurement points, multiple final control elements, or multiple controllers, as discussed below. Selectors are used to improve the control system performance as well as to protect equipment from unsafe operating conditions. 

CONTROL AND STARTUP OF A 3-STAGE CSTR CASCADE MULTIPLE OPERATING STATES AND COUNTERCURRENT COOLING... 

These instmments are engineered to a high degree of complexity and allow the reliable control of the multiple operations and reaction conditions encountered in the automated synthesis protocol. This topic has been extensively covered in some recent reviews (30-40), and we will limit our discussion of automated SP discrete synthesizers to the implications of their use for the synthesis of small organic molecules on SP. 

The PROTECT architecture consists of sensors deployed in various subway stations, complemented by closed-circuit television (CCTV) cameras that have automated and manual pan-tilt-zoom capabilities. These sensor and camera combinations provide data continuously to a centralized chemical-biological emergency management information system (CB-EMIS developed by Argonne National Laboratory) located in a centralized WMATA operations control center. In addition to the sensor and video data from the stations, train operation data and ambient meteorological data are also ported to the CB-EMIS system. Under normal operations, CB-EMIS can provide operator access to the multiple fixed and movable cameras throughout the metro system to assist law enforcement officers or firefighters. It also monitors the status of the sensor systems deployed in the metro. 

This industry, like nearly all others, has seen the positive impact of the introduction of computers and automation in the manufacturing facilities. The first impact was in the automatic control systems that are used to maintain accurate and reproducible operating conditions for reaction and isolation systems. This was extended into the integration of multiple operations under computer control often eliminating or at least minimizing people intervention. 

Inherent and required consistency and coherency of available information Operational control and performance situations will often deal with information that is relatively consistent and coherent. The information in strategic planning and management control situations is often inconsistent and perhaps even contradictory or incoherent, especially when it comes from multiple external sources. 

Covert change sometimes occurs in the form of a ripple effect through utility systems. If a facility has multiple operating areas, each of which is connected to a common utility system, then each area may make properly controlled changes to its own operation but may not realize that it is having a system effect. An example of a ripple effect change that can occur in a utility system is shown in Figure 10.1. 

Room 101/108 Door control (enables door movement) Inadvertent door motion Electrical malfunction (contact closure or short) or multiple operator errors Observata on ofdoor movement None None... 

In current closed systems, such as second-generation and third-generation cellular environments, the core network is owned by a sole operator, who is responsible for managing all aspects of the system including security and QoS provision. However, as previously explained, the heterogeneity of future networks leads to a new open architecture for the core network, where the infrastructure is not controlled by a single operator. Rather, multiple operators will have to coexist in the core network. To deal with the interoperability issue between the different operators, the Y-Comm group in [1] and the Daidalos II Project in [6], adopted and... 

Does not protect nonoperators. Safety distance may be excessive for slow-to-stop machines. Sophisticated control circuit required for multiple operators and multiple operator location. May not protect if machine stopping time is variable. 

Multiple Operators Use of more than one person can provide redundancy. In aircraft, a pilot and a copilot can perform the same function. If one is incapacitated, the other can take over (parallel redundancy). Another example (series redundancy) might be atwo-person press. Both operators may face the hazard of getting caught in the machine when it is in motion. If each operator has a two-hand control, all four hands of the operators must depress the switches before the machine will operate. 

Multiple Operators Ifthere is more than one operator for a machine, each should have a separate set of controls. Each set of controls must link to all other sets. All operators must have their hands free of the point-of-operation before the machine can start its motion. In addition, when there are multiple operators, each should have an emergency shutoff within reach from their work position. 

The plant operation is controlled by the integrated automated control system on the basis of multiple redundant control computing devices with automatic diagnostic of software-hardware The technical capabilities of the computing devices allows continuous and periodical diagnosis of the state of the most important elements and the reactor plant as a whole by all presently used methods which considerably reduces the probability of sudden failures... 

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