Indicators, Recorders, Gauges, and Digital Readings This has the effect of changing the process enough to bring the process variable in line with the set point. Such a change might be a valve opening or closing, or a heating element increasing or decreasing in temperature. Typically this might be a valve or heating element, which causes a change in the operation. Secondly, after comparing the variable reading to some predetermined value (or set point), they send out a controlling signal to another element in the system. Instruments have two basic jobs, and may combine both tasks into one device.įirstly they measure and indicate the value of a process variable, which may then show up as information on a gauge, recorder, etc. The devices that are used to monitor and control these process variables are generally known as process instrumentation or simply instrumentation. Parameters normally measured and controlled in a process industry are: – I / P converter is a transducer converting the current input to equivalent air output and P / I converter is converting air input to equivalent current output.
Transducers– Transducers are signal converters used to convert signals from one form to another form.Here the controlled variable is temperature and manipulated variable is hot water flow. controlling the flow of hot water through a heater to control the temperature of the gas passing through it. Manipulated variable– The variable that we adjust to control another variable is called a manipulated variable, e.g.Controlled variable– The process variable that we control is the controlled variable.Output- Output is normally called for the output signal from a controller.It is the difference between the PV and SP. Deviation– Deviation is also called OFFSET.SP (Set point)– SP is the desired value of a process parameter set by the operator to control a process.PV (Process variable)– PV is the process parameter like, flow, level, pressure, temperature, speed, etc that we measure from a process (field).This ensures that the processes we are working with are operating at safe, and accurate. From production to processing to storage and export, process instrumentation and control plays a critical part in assuring the flow rates, temperatures, pressures and liquid levels in the desired ranges. Process control and instrumentation is used in all aspects of the oil and gas industries. In many areas of our industry, the trend is towards fully automated systems using digital controllers monitored and operated by computer. While there are process control systems, which have to be adjusted by a person reading a gauge, or any indication, many instrumentation and process control systems used in industrial settings are automated. This controlling action will be either turning the valve handle or pressing the accelerator pedal to make changes in the process to bring it in line with the desired result. The person visually gathers information about the flow rate of water or the speed of the automobile and performs a controlling action. In both of these examples, a person acts as a controller in the process.
#Temperature recorder controller trc driver
The driver pushes down or lets off of the accelerator pedal to maintain the speed setting at a predetermined speed.
The process control part of this task would be the operation of the accelerator pedal, which controls the flow of petrol to the engine. The instrumentation part of this process would be the speedometer. As the level of the water reaches some predetermined point on the tank, commonly called the set point, the flow of the water is gradually decreased and ultimately stopped.Īnother example would be someone maintaining a certain speed on a speedometer in a car. The process control part of the task would be the control of water flow from the tap (a simple valve). The instrumentation part of this task would be the tank with markings on the side, indicating volume. In fact, instrumentation and process control is found in almost every process or devices you will ever face, on or off the job.Īn example of a simple process control and instrumentation concept would be someone filling a tank with water from a tap to some preset level. Instrumentation and control processes are found in all the systems you will face, from the simplest valve to the most complex processing facility. The concepts and principles you will learn about instrumentation and process control are applicable to almost every task you undertake in the oil and gas industries.
0 kommentar(er)
