Alarm display

Operator interface with system is via a two position operator s console. Each operator has two working color CRTs and a custom keyboard. A fifth single CRT dedicated to alarm displays is shared by both operator positions. Additional equipment includes multi-pen chart recorders, alarm logger and report typer. The operator monitors operations via continuously updated custom graphic displays, status and alarm reports on the CRTs and can call up displays and execute control commands by using special function push buttons in the keyboard. 

Roth, E. and OHara, J. (1999), Exploring the Impact of Advanced Alarms, Displays, and Computerized Procedures on Teams, Proceedings of the Human Factors, and Ergonomics Society, 43rd Aimual Meeting, pp. 158-162. 

Table IX/4-1.2-3 Average Alarm Rate Following an Upset (IEEMU191 Quidelines) No. of Alarm Displayed in 10 min Following a ...

Many functionality items are mandatory and some are recommended. There could be varieties of displays suitable for specific plant applications. Some of the typical alarm displays could include but not limited to the following ... 

The key point here is to recognize the additional factors that affect the PFD. The two main factors that affect the SIL of SIS with operator action are human errors and support system reliability. Human error essentially is the failure of the operator to respond correctly to the alarm/display and to take the corrective action(s) necessary to return the process/facility to a safe state. As already discussed in previous chapters... 

Switeh off automatic with selected alarm display... 

Various alarm follow-on fimctions (purging etc.), selectable before switching off the machine Optieal alarm display with selectable duration Part eoimter, cycle coimter, run time counter Mould blow programme, variable blow and start time... 

The BPCS HMI will serve as the primary human-machine interface for the SIS. All alarm display functions will be implemented in the BPCS HMI no hardwired annunciation is required. An engineering/maintenance interface will be located in a secure location. 

Alarm display-pressure, flow, air, pH, conductivity, valve position, tank level... 

After setting up the test system, the inspeetor can fully concentrate on scanning the test zones. In the case of coupling failure, an acoustic alarm horn will sound and a visual alarm message will appear on the PC display. 

Figure 18.24(b) illustrates the use of a leakage current monitor. The instrument can be used to display or monitor on a computer remotely and store data at intervals as required to provide diagnostic information. Now it is easier to take corrective measures in time. The instrument can also be programmed to give an alarm at a preset value of I, when the actual operating conditions exceed this. 

During testing, all alarm and shutdown funetions must be simulated to verify proper operation of the annuneiator display. The test teehni-eian must plaee his initials next to the tabulated set points as verifi-eation of eompletion. 

Representational layout of control panels. Where the physical location of items is important, for example, area displays in fire control systems, the layout of the displays on a control panel should reflect the geographical layout of the plant. In other cases a functional arrangement of the elements of the process plant will be appropriate, for example, when monitoring the status of the system via an alarm panel. 

Design according to frequency of use or importance. Controls and displays that are frequently used or are of special importance (e.g., critical alarms), should be placed in prominent positions, for example, near the center of the control panel. 

Supports the Early Detection of Abnormal Process States Although some diagnostic information is available in the activated alarms, the workers still need to know the size of any deviations from the target states and require a concise picture of those critical parameters which are in alarm and those which are nearing it. This information is available on the overview display and facilitates the early detection of process deviations. 

Design of human-machine interfaces (e.g., process information displays, alarm systems, plant labeling)... 

The portable vibration analyzer incorporates a microprocessor that allows it to mathematically convert the electrical signal to acceleration per unit time, perform a TFT, and store the data. It can be programmed to generate alarms and displays of the data. The data stored by the analyzer can be downloaded to a personal or a more powerful computer to perform more sophisticated analyses, data storage and retrieval, and report generation. 

Predictive maintenance systems use two methods of detecting a change in the operating condition of plant equipment static and dynamic. Static alert and alarm limits are pre-selected thresholds that are downloaded into the microprocessor. If the measurement parameters exceed the pre-set limit, an alarm is displayed. This... 

The computer does not display alarms or limit values and by intention, trips are independent. Thirty seconds is the normal logging interval as this is capable of showing the detail of the most abnormal change, e.g. runaway exotherm. However, intervals as close as six seconds are possible. Logging can be continuous for up to 24 hours, allowing around 400,000 data points to be recorded per batch/dlsc. 

Err" signal errors are automatically shown on the LED display in the case of a defective pH electrode or faulty temperature sensor (Pt 100) and for incorrect buffer two set points can be set over any part of the pH, mV or 0° C scale, which when exceeded starts an alarm and/or allows readjustment of dosing valves or pumps via an interface circuit. 

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