Control operator station

The central computer is called the master terminal unit, or MTU. The MTU has two main functions to periodically obtain data from RTUs/PLCs and to control remote devices through the operator station. The operator interfaces with the MTU using software called human machine interface (HMI). The remote computer is called the program logic controller (PLC) or remote terminal unit (RTU). The RTU activates a relay (or switch) that turns mechanical equipment on and off. The RTU also collects data from sensors. Sensors perform measurement, and actuators perform control. 

A control panel receives information from the sensors and sends it to an appropriate location, such as to a central operations station or to a twenty-four-hour monitoring facility. Once the alarm signal is received at the central monitoring location, personnel monitoring for alarms can respond (such as by sending security teams to investigate or by dispatching the fire department). 

Each of the independent controllers is linked to a human-machine interface (HMI) network. Dedicated HMI operator stations are assigned to each area, with an appropriate number of redundant stations providing backup in case of maintenance or breakdown. A development station permits tooling changes between campaigns to be carried out at the same time as systemiza-tion is carried out on the individual areas. A redundant set of historical data collection stations ensures that all of the data are collected and stored for both regulatory... 

In an entirely new plant, however, various DCCS components will be housed in local control rooms (LCR) or in outstations. The primary operator stations (OS) and... 

This consists principally of the host which is used to supervise several process areas and may well have six or more data highways linked to it. Hosts are powerful computers with their own operator stations and other peripherals. They are an integral element of modern control systems and only very small processes may be controlled and monitored effectively without a host. However, if not configured properly, a host computer can be overloaded quite easily and will then fail to operate satisfactorily. One serious loading problem for a host is the fast scanning rate required for DDC loops (usually once per second and up to three times per... 

A number of the basic characteristics of operator stations (OS) are described in Section 7.19.4. Distributed computer control systems normally offer two types of operator station, a stand-alone OS, and a host-dependent OS. Both provide a logical display hierarchy which, if properly configured, improve significantly the... 

CON Concentrator. OS Operator station. CM Control module. PLC Programmable controller. DM Data acquisition module. HC Hiway controller. 

Workstations. Workstations are the most powerful computers in the system, capable of performing functions not normally available in other units. A workstation acts both as an arbitrator unit to route internodal communications and as the database server. An operator interface is supported, and various peripheral devices are coordinated through the workstations. Computationally intensive tasks, such as real-time optimization or model predictive control, are implemented in a workstation. Operators supervise and control processes from these workstations. Operator stations may be connected directly to printers for alarm logging, printing reports, or process graphics. 

Typically, a remote afterloader is a shielded cell or treatment room. Long cables pass through the wall of the room from an operating station outside the room to a patient treatment position inside the room. Radioactive sources are attached to the cables at the patient treatment position. With the patient in the treatment room and the shielded room door closed, the sources are advanced to the treatment position in previously installed applicators by means of the cables and a mechanism in the control system outside the treatment room wall. Our goal was to adapt sources containing up to 200 yg of 252 f to use in these remote afterloaders. 

Pharmaceutical analysis [18-20] has undoubtedly been the most receptive field to robotic applications, probably due to the suitability of robots for quality control operations. To a much lesser extent, robots have been used in environmental monitoring, in the treatment of biological samples (clinical chemistry) and in elemental organic and inorganic analyses. It is worth pointing out the small number of references available on the use of robotic stations for the analysis of foodstuffs or materials of industrial interest. 

Crew Station/equipment characteristics The crew station design module and library is a critical component in the MIDAS operation. Descriptions of discrete and continuous control operation of the equipment simulations are provided at several levels of functiontil deteiil. The system can provide discrete equipment operation in a stimulus-response (blackbox) format, a time-scripted/ event driven format, or a full discrete-space model of the transition among equipment states. Similarly, the simulated operator s knowledge of the system can be at the same varied levels of representation or can be systematically modified to simulate various states of misunderstanding the equipment function. 

The control valve station should be located to facilitate operation and maintenance. 

Operator stations. Operator stations typically consist of color graphics monitors with special keyboards to perform dedicated functions. Operators supervise and control processes from these workstations. Operator stations may be connected directly to printers for alarm logging, printing reports, or process graphics. 

Control valve stations are preferably located at grade for the inline unit and at main operating levels for the vertical arrangement. It is not absolutely necessary to locate control valve stations in such a way that pneumatic or electrical interconiieaions are kept to a... 

Currently open system designs with global bus architecture and local area networks (LANs) are being used for computer control, as shown in Fig. A.l. Unlike earlier networks, which were normally isolated, the LANs are often connected to other networks via gateway devices. The traditional host computer functions are divided functionally and are implemented in separate autonomous computers, which share the same data bus. When more than one operator interface node is installed, the operator interface to the process can be maintained even when several operator stations fail. A DCS for process control is fundamentally the same as for other real-time distributed systems used in business data centers or server facilities (Herb, 1999 Lewis et al., 2006), although specialized hardware such as data acquisition equipment is required. 

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