Instrumentaton and Control System Blog

vanderVoort Cyber Security and SCADAhacker have teamed up to offer advanced course: ‘Understanding and Securing Industrial Control Systems’ this 5 day course will be held twice: A - June, 17-21, 2013 B - June, 24-28, 2013 Location: The Hague, The Netherlands See: www.v-cybersecurity.nl or www.scadahacker.com

Whether to migrate to new process control system and decommission the existing one; is a question asked by many plant owners. It is not only a matter of cost but lot of human resources and time is required to accomplish this successfully. Migrating to a new platform whether it is same OEM/vendor or new, is a question to be answered by the persons working for the plant. If this question is asked to vendors/sellers, then no one answer would be obtained.  New seller would provide arguments in the favor of new platform.  He will first focus on the disadvantages of the existing system and may argue following in favor of the migration. Parts will eventually become obsolete and not supported by the OEM. Degrading parts of the system will tend...

Quantitative evaluation of system reliability and integrity often involves probability related calculations. Basic probability theory, in general, is sufficient to cover these calculations. Here, I will describe basic probability theory. Simple probability (1 of 2) What is the probability that a card drawn at random from a deck of cards will be an ace? Since of the 52 cards in the deck, 4 are aces, the probability is 4/52. In general, the probability of an event is the number of favorable outcomes divided by the total number of possible outcomes. (This assumes the outcomes are all equally likely.) In this case there are four favorable outcomes: (1) the ace of spades, (2) the ace of hearts, (3) the ace of diamonds, and (4) the ace of cl...

Networking and Internet security has become an important issue in the Industry Automation. This blog takes three very basic terminologies which are used by us in routine. Socket A socket is the endpoint of a connection over a TCP/IP network, much like a phone is the endpoint of a connection in the telephone network. A socket is the combination of a TCP port and an IP address. Ports are logical interfaces for applications, and they are assigned numbers. For example, The Web’s HTTP protocol is located at port 80. Using the telephone analogy, the TCP port is then like a telephone number and the IP address is the location of the phone. A socket is like a phone that has been assigned a phone number. However, a typical host can have many socke...

The management of alarms is not just about operator displays! The entire system is involved. In some U.S. power plants, alarm systems designed to warn plant operators of abnormal operating  conditions have become overburdened with insignificant alarms. These alarm systems do not provide alarms with proper priorities, and in some cases are not well maintained.  An effective alarm management implementation is dynamic. For this reason, alarm best practices and the application of a continuous improvement rationale are central to this important activity. As alarm systems become less effective, they diminish the effectiveness of all automation.The first step toward an effective alarm management solution is to develop a sound Alarm Management Phil...

The purpose of an anti-surge control is to keep the compressor from going into surge on reduced flow. Surge is an instability exhibited by a centrifugal as flow is reduced below the surge point. An anti-surge control is recommended for all centrifugal compressor applications. Pipelines transporting gases and vapours are invariably dependent on centrifugal or turbo-compressors for the propulsion of these fluids. Under normal operation, with the compressor running at any constant speed there is a specific relationship between the pressure head across the compressor and the flow through it. But this stable relationship can be disturbed by sudden changes in flow, pressure and density, usually caused by sudden variations in demand downstream of...

ESD/ESV valves are one of the defense in protection layers against process hazards. These valves have a function which requires much more reliable performance than standard remotely operated on-off valves. IEC 61508 is a globally recognized new safety standard specific to process industry. Very strong guidelines are given there to process operators to test and prove the availability and functional safety of the safety loop including the final elements and ESD valves.Part 1 of the IEC 61508 demands certain documentation requirements for the development of safety critical devices. The selection of a specific type of safety valve is governed by several factors: -    Cost-    Valve construction-    Approvals-    Operating characteristics-    T...

LOPA is a semi-quantitative risk analysis technique. Therefore it is a midway approach between HAZOP and a quantitative risk assessment (QRA) in terms of its rigorousness. This technique evaluates risks by orders of magnitude of the selected accident scenarios and builds on the information developed in qualitative hazard evaluation (e.g. PHA).  During a process hazards analysis (PHA), a team is responsible for assessing the process risk from various process deviations by determining the potential frequency and consequence of the incident. Plants are protected by various layers of protection: Plants are protected by various layers of protection: Pressure Relief Devices Flare Systems Fire Suppression Systems Safety Instru...

An ultrasonic flow meter is a type of flow meter that measures the velocity of a liquid or gas (fluid) by using the principle of ultrasound. Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and against the direction of the flow. Ultrasonic flow meters are affected by the temperature, density and viscosity of the flowing medium. They are inexpensive to use and maintain because they do not use moving parts, unlike mechanical flow meters. There are three different types of ultrasonic flow meters. Transmission (or contrapropagating transit-time) fl...