Backup system

Although digital control technology was first apphed to process control in 1959, the total dependence of the early centralized architectures on a single computer for all control and operator interface functions resulted in complex systems with dubious rehability. Adding a second processor increased both the complexity and the cost. Consequently, many installations provided analog backup systems to protect against a computer malfunction. 

A differential pressure controller acts in split range on the inlet control valve and the bypass valves. The differential pressure governor is retained as the standby and backup system. 

A critical installation should have the metal temperature sensors in the thrust pad. Axial proximity probes may be used as a backup system. If metal temperatures are high and the rate of change of those temperatures begins to alter rapidly, thrust-bearing failure should be anticipated. 

Now let us consider utility failure as a cause of overpressure. Failure of the utility supphes (e.g., electric power, cooling water, steam, instrument air or instrument power, or fuel) to refinery plant facihties wiU in many instances result in emergency conditions with potential for overpressuring equipment. Although utility supply systems are designed for reliability by the appropriate selection of multiple generation and distribution systems, spare equipment, backup systems, etc., the possibility of failure still remains. Possible failure mechanisms of each utility must, therefore, be examined and evaluated to determine the associated requirements for overpressure protection. The basic rules for these considerations are as follows ... 

Backup systems which depend upon the action of automatic cut-in devices (e.g., a turbine-driven standby spare for a motor-driven cooling water pump, with PLCI control) would not be considered an acceptable means of preventing a utility failure for normal pressure relief design purposes, even though their installation is fully justified by improved continuity and reliability of plant operations. 

The customer will advise on the format of the advanced shipment notification (ASN). A computerized system will give you flexibility such that you are able to transmit the information immediately the shipment is loaded. You could use a fax machine as your backup since transmission is nearly as fast but this is likely to present the customer with data-handling problems. A computerized transmission feeds the data directly onto the customer database, by-passing the manual data-entry stage. Your backup system should do the same in order that your customer perceives no noticeable change in the information. 

Arrange for backup systems in the event that the computerized system breaks down. 

Dedicated web sites have been developed for randomizing subjects over the Internet. Internet-based systems have also been widely used for subject enrollment and randomization. Some of these systems employ dynamic randomization number allocation [49, 50], whereas others use pregenerated randomization numbers. Various issues must be addressed when using the Internet for randomization, such as the availability of Internet access and the need for a backup system to ensure the continuation of operation when the web site is inaccessible [51]. 

In theory, the application of radon barriers should be adequate to avoid elevated radon levels in houses. In practice, however, a backup radon mitigation system has been found essential for maintaining indoor radon concentrations below 4 pCi/L in most homes studied. In the recent radon-resistant residential construction projects conducted by U.S. EPA and/or private builders, several of the homes designed to be radon resistant have contained radon concentrations above 4 pCi/L. In each of those houses, a backup system consisting of an active (fan-assisted), or passive (wind-and-stack-effect-assisted), SSD system was installed at the time of construction. When mechanical barriers failed to adequately control radon, the soil depressurization methods were made operational. 

Require backup systems to monitor flame and provide pilot burning. 

Fire pumps should be solely dedicated to fire protection. They may be used to feed into a backup system for emergency process cooling but not as the primary supply. If such backup is allowed is should be tightly controlled and easily accessible for prompt shutdown in case of a real emergency. 

I-3.6.3 Uninterruptible power sources or redundant backup systems shall be considered to help prevent overpressure/unintentional shutoff situations caused by power outages. 

In addition to specific docmnentation described above, laboratories must retain aU schedules, logs, and reports of system backups, system failures, and recoveries or restores. 

Mr. Wallace is writing a budget request to upgrade his personal computer system. He wants to purchase 4 mb of RAM, which will cost 100, two new software programs at 350 each, a tape backup system for 249, and an additional tape for 25. What is the total amount Mr. Wallace should write on his budget request ... 

How do you define health Many would say health is more than just the absence of disease rather, a healthy person tends to be happy and vital, feeling physically and mentally centered and balanced. The immune system is the body s foundation for feeling healthy. It plays a critical role in protecting the body from illness. It even has a backup system so that if one part of our immunity is compromised, another mechanism is ready to participate in the body s protection and wellness. 

The selection of non-reclosing devices as a secondary or backup system is, however, a more widely accepted solution. 

Will this CRS include a data backup system that needs to be validated or will it utilize an existing validated backup system ... 

Fernandes, A.P., and Holmgren, A. 2004. Glutaredoxins glutathione-dependent redox enzymes with functions far beyond a simple thioredoxin backup system. Antioxid. Redox Signal. 6 63-74. 

Inadequate control systems and safety backup systems. 

In digital controllers, it is desirable to set the sample time at about one quarter of the period of surge oscillation, or at 0.3 seconds, whichever is shorter. If a flow-derivative backup control is used, the sample time must be 0.05 seconds or less, because if it is slower, the backup system would miss the precipitous drop in flow as surge is beginning. 

The concept of a poison contained within a bullet is not new and has been experimented with over a long period of time. As all poisons, in the quantities capable of being administered via a bullet, take some time to kill, the tactical use of such ammunition is of limited military or civilian use. However, it is an attractive concept for an assassin. If the bullet itself fails to kill, the backup system of the poison offers a twofold method of attack. 

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