Supervisory control system

Control Devices. Control devices have advanced from manual control to sophisticated computet-assisted operation. Radiation pyrometers in conjunction with thermocouples monitor furnace temperatures at several locations (see Temperature measurement). Batch tilting is usually automatically controlled. Combustion air and fuel are metered and controlled for optimum efficiency. For regeneration-type units, furnace reversal also operates on a timed program. Data acquisition and digital display of operating parameters are part of a supervisory control system. The grouping of display information at the control center is typical of modem furnaces. 

The automation concept implemented at Conroe is called computer production control (CPC).2 CPC systems are driven by a general purpose process-control computer (48-K core memory) centrally located and programmed to monitor production and equipment operations and perform oil and gas accounting. As shown in Fig. 11, the computer is connected to a supervisory control system with a computer interface unit (CIU) to provide remote data acquisition and control function capability. 

The 6ize of the field, its geographic location, and the tight line transportation system provide some challenging operational and control problems. These problems are identified showing how automation has been used to solve then. This includes the use of an integrated supervisory control system and a distributed process control system designed to meet the control needs of future production facilities as the field proceeds to ultimate development. 

Wave models were successfully used for the design of a supervisory control system for automatic start-up of the coupled column system shown in Fig. 5.15 [19] and for model-based measurement and online optimization of distillation columns using nonlinear model predictive control [15], The approach was also extended to reactive distillation processes by using transformed concentration variables [22], However, in reactive - as in nonreactive - distillation, the approach applies only to processes with constant pattern waves, which must be checked first. 

From a practical perspective, this is the model that should be used to design a (multivariable) controller that manipulates the inputs us to fulfill the control objectives ys. It is important to note that the availability of a low-order ODE model of the process-level dynamics affords significant flexibility in designing the supervisory control system, since any of the available inversion- or optimization-based (e.g., Kravaris and Kantor 1990, Mayne et al. 2000, Zavala... 

Describe a supervisory control system for the plant of Example 23.4 (Figure 23.10) using as local controllers (a) analog devices controlling one loop each, and (b) microcomputers capable of handling four loops each. How would you select the loops to be controlled by each local microprocessor ... 

Most process plants use supervisory control systems, shown in Figure 10-9, in which the computer acts as a supervisor by adjusting the setpoint of a controller. The controller adjusts a valve to keep the process variable at the setpoint dictated by the computer. In Direct Digital Control, the computer bypasses the controller and resets the valve position directly as shown in Figure 10-10. All setpoint functions in DDC ire contained within the computer. 

Direct control system level This is the lowest level of automated system in the production process, including the distributed control system used in production devices and the fundamental automated equipment used offsite. The parameters of the production process are measured and controlled by the automated system. They also receive instruction from the supervisory control system level and accomplish the process operation and control. 

Supervisory control system level The system in this level fulfills supervisory control of main production links in the whole production process. According to the instructions from the sched-... 

A supervisory control system could collect information mi the flow and water temperature of the shower and, in concert, change the amount of cold water and hot water to meet both objectives simultaneously. The system is described in Fig. 9.10. 

Fig. 28.1a-c. Technical classification of robotic systems a Supervisory controlled system, in which the surgeon plans the operation off line and the robot performs the specified motions autonomously under the supervision of the surgeon, b Telesurgical system, in which the robot is under direct control of the surgeon with an on-line input device, which is typically a force feedback joystick (master), c Shared control system, in which the robot and surgeon share control of the surgical instrument. [Modified from Nathoo et al. (2005) with permission]... 

Markl D, Wahl PR et al (2013) Supervisory control system for monitoring a pharmaceutical hot melt extrusion process. AAPS PharmSdTech 14 1034-1044 Montgomery DC, Keats JB et al (1994) Integrating statistical process control and engineering process control, J Qual Technol 26 79-87... 

Unlike simple data logging systems, supervisory control systems are designed to restrict the flexibility of the operator by "supervision" of his actions. In these systems the operator can interact with the plant through the keyboard/workstation to start or stop pumps, open valves and change PID controller set points. The three-term controllers may be conventional electronic controllers, linked to the supervising system, or software algorithms programmed into a PLC. 

The sophistication of the supervisory control system depends somewhat on the level of plant automation. In principle, all valves on the plant could be remotely actuated, allowing almost all procedures including start-up and shut-down to be "run" by the computer. In practice, such levels of automation are not cost-effective and a compromise is normally reached on the level of plant automation. 

On the basis of the foregoing statements, the usual control philosophy adopted when designing a supervisory control system is as follows ... 

Readers wishing to study control in more detail can examine experience with a reactor supervisory control system in the paper by Tnmnen et al. (1999). More recently, a number of papers have started to address control of PI systems in more... 

A ProSigma application typically consists of a control side (e.g., a device at a supervisory control system) and an object side (e.g., a device at a field object). 

Stanton, N.A. and Ashleigh, M.J. (2000) A field study of team working in a new human supervisory control system. Ergonomics, 43, 1190-1209. 

Stanton, N.A. and Baber, C. (1995). Alarm initiated activities an analysis of alarm handling by operators using text-based alarm systems in supervisory control systems. Ergonomics, 38, 2414-2431. 

Wang, X. Ray, A. 2004. A language measure for performance evaluation of discrete event supervisory control systems. Applied Mathematical Modelling no. 28 817-833. 

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