Instrumentation And Control
Why does the introduction of
instrumentation (id) is essential in an industry? What you need to know about how the
instrumentation basic and measurement concepts? Some of the other questions the reader into thinking and the basis of this material?
Instrumentation is a tool that has a special and particular functions. There are several kinds of instrumentation at the plant and industrial processes, among others:
1.
As a measuring instrument sensor / transducer : A device used to sense the amount of process to be measured and the change of a quantity (eg: temperature) to form another scale (eg electrical quantities)
2. Instrumentation control (Controller) : is a tool used to perform calculations based on the signal controller feedback (process variable) and references signal (set point).
3.
Control Valve (Final Control Elements) : A device used to perform the control actions based on signal control.
On this topic emphasis on the introduction of existing measurement tools in the process industry, the concept of measurement, any measurement tool used to, process control and related matters by way of calibration and system protection
Terminology instrumentation is an important part to take advantage of well instrumentation.
Signal in the measurement
Every time we make a measurement, we should already know with certainty what will be measured, and what will be produced. Here are the terms of the signal:
1.
Variable Measurement (measured variable): is a physical quantity that is pengukuran.contohnya:
temperature, pressure, flow rate,
level etc..
2. Signal measurement (mesuared signal): is a variable measurements in the form of electrical, mechanical, pneumatic or other variables entered in the instrumentation, or in other words is a variable measurement signals generated by any sensor or transducer.
3. The input signal is a signal put / get in on an element, or system instrumentation.
4. The output signal is a signal generated / incurred by certain elements, instrumentation or other systems.
5. Measurement area (range) is an area bounded by the maximum price and the minimum price of a quantity measurable. For example: 0 - 150 ยบ C, 1-10 kg 4-20 mA, 3-15 psi etc..
6. Measuring the area (Span) is the difference between an upper limit to the lower limit of the measurement area. For example, for a measurement 4-20 mA 16 mA measuring the area have.
QUALITY MEASUREMENT RESULTS
From the steps of measurement known figure measurement results that can be observed from the needle or scala gauges. The question right now. Are the numbers designated gauge reliable? or how the errors that may be contained in the number of bookmarks. To determine the
level of error (accuracy) measure in general can be seen in the list of standard specification or calibration tool.
Some examples of terminology related some precision:
a) Accuracy (Accuracy) is a measure that states how much the instrument shows a distorted price / close to the actual price.
b) Repeatability (Repeatability) is the extent to which the instrument can show the same output, for a fixed input, if repeated measurements
c) Sensitivity (sensitivity) is the ratio between the change in output to changes in input at steady state.
d) Resolution is the smallest size or scale of measurement that can be read from the scale instrumentation.
e) Threshold is the smallest input value that can be read at the lowest scale (lower boundary)
f) Hysterisis is a situation where the calibration track when input prices going up is not the same as when the trajectory calibration if input prices lowered.
g) Dead Band is an area measuring where the input does not result in any output. measurements include:
Measurement of pressure
Will be presented examples of the kinds of pressure measurement system, which is common practice in the industry such as industry-industry
.
Range of pressure measurement range of elements ranging from simple, manometer U, bellows, diaphragms, strain gage, etc.. Similarly, the flow measurement,
level measurement and measurement of the
temperature at which the description is based on the drawings
With this method it is expected that the candidate is not qualified to be a reference and further difficulty in analyzing the variety kinds of process control instrumentation that would newly discovered later after working in the field later
Pressure Calibration
is the process undertaken to ensure that the value of zero, span, accuracy and linearity of a pressure instrument in accordance with the actual pressure value
Accuracy - determined by comparing the pressure readings with the test instrument gauge standard for some point to do readings at random.
linearity - determined by giving increasing and decreasing pressure and see the response of the pressure instrument is formed of linear equations or equations arch / polynomial. If not then it should be linear adjustment.
Zero - is the value of pressure in unstressed conditions (1 atmosphere).
span - is the difference between the maximum value to the minimum value. While the range is a minimum to a maximum value
Two common types of calibration:
1. Bench Calibration - instrument that brings pressure to shop and do the calibration. Standard toolused is DWT (Dead Weight Tester) is a tool that to convert dead weight of a metal to be pressure. Since weight is a force and the force one unit area is the pressure. Besides compared with DWT with pressure already dead (not likely change) pressure than the instrument is still Certified Test Gauge Standard.
2. Field Calibration - calibration in the field is done by injek pressure on pressure instrument with Hand Pump that line was installed parallel to the Certified Test Gauge Standard. Pressure readings should be the same as the readout instrument Test Gauge Standard. Field calibration is generally performed only to ensure that during the pre-commissioning of the pressure instrument can still work well. In addition to local readings pre-commissioning also need to ensure Zero, Span, and Linearity Accuracy of the delivered system pressure monitor (PLC / DCS).
Instrumentation and Controls - is a complementary tool to support the accuracy of measurement and automation / control system of power tools, machinery, tools also processing or production of online, real time, and reduce man power amp If you imagine for instance the following example:
An oil refinery or oil processing at the downstream oil & gas major components that will be seen there are distillation columns, pipes, cooler, and Vesel-Vesel for separation. Which instrument and control?. Instrumentation devices only small patches all over distillation columns, piping, vessel, as well as tanks, and others. Control is a set of tools that receive information and give orders to his instrument. Control function is to perform automation / control over the process is ongoing. Its presence is vital when the accuracy of the results, continuity processes, process safety is also a major consideration in the process industry.
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