Proportional integral derivative, temperature control

The Pt catalyst was mounted on a copper block and could be translated, tilted and rotated by means of a manipulator fitted with a differentially pumped rotary feedthrough. The Pt foil (Advent, purity > 99.99%) could be resistively heated. The mounting allowed to work in the temperature range 300-1600 K using direct sample heating with a proportional-integral-derivative (PID) control unit. The temperature of the catalyst was measured by a Ni-NiCr thermocouple spot welded to the Pt-foil. Clean platinum surfaces could be obtained by applying several cycles of Ar" " ion... 

Heat is lost from the surface by conduction through the susceptor and mount, by forced convection of gas over the substrate, and by radiation to the reactor walls, provided the temperature of the substrate is sufficiently high. Endothermic chemical reactions also result in heat loss from the film. The substrate temperature is monitored with a thermocouple or an optical pyrometer and controlled using a traditional proportional-integral-derivative (PID) controller and power source. 

Plastic Temperature. Correct temperature and uniformity are crucial for a consistent process. Monitoring of plastic temperature is difficult and rarely utilized in the industry. Control of temperature is done via thermocouples partially embedded into the barrel wall, usually three to four along the length of the barrel. The actual molten plastic is not monitored for temperature and >90% of the temperature values provided as data are barrel wall temperatures that can be off by 25°C (45°F). Temperature control is done via proportional-integral-derivative (PID) controllers or PID algorithms on computer controlled presses. Calibration of thermocouples is seldom done. PID temperature control of the nozzle tips is also important, yet 40% of the industry uses variacs. 

Temperature proportional-integral derivative Pinpoint temperature accuracy is essential to be successful in many fabricating processes. In order to achieve it, microprocessor-based temperature controllers can use a proportional-integrated-derivative (PID) control algorithm acknowledged to be accurate. The unit will instandy identify varying thermal behavior and adjust its PID values accordingly. 

The temperature control was modeled by using these defining equations for a PID (Proportional-Integral-Derivative controller) algorithm ... 

The equipment used in the unit operations is complex and microprocessor controlled to allow the execution of process recipes. However, advanced control schemes are rarely invoked. The microprocessor adjusts set points according to some sequence of steps defined by the equipment manufacturer or the process operator. Flows, pressures, and temperatures are regulated independently by off-the-shelf proportional-integral-derivative controllers, even though the control loops interact strongly. For example, fluorine concentration, substrate temperature, reactor pressure, and plasma power all influence silicon etch rates and uniformity, but they are typically controlled independently. 

PID See temperature proportional-integral derivative control algorithm. 

The relevance of contact resistances in SPS process has been simulated and confirmed, with the simulation shown in Fig. 6.15 as an example [4]. The system simulated is a Model 1050-Sumitomo SPS, where a solid graphitic cylinder is inserted into the die. The 2D cylindrical coordinate system of coupled thermal and electrical problems is numerically solved by using Abaqus (FEM). The heat losses due to radiation from all exposed surfaces, except those on the ends of the rams, have been considered, where a constant temperature of 25 °C is used for the simulation. Thermophysical parameters of all materials are available in that study. A proportional feedback controller based on the outer surface temperature of the die is modeled, in order to determine the voltage drop applied at two ends of the rams. This controller is used to imitate the actual proportional integral derivative (PID), which is observed in real SPS facilities. It is used to apply electric power input to the system when experiments are conducted in terms of temperature controlling. 

Process-variable feedback for the controller is achieved by one of two methods. The process variable can (I) be measured and transmitted to the controller by using a separate measurement transmitter with a 0.2-I.0-bar (3-15-psi pneumatic output, or (2) be sensed directly by the controller, which contains the measurement sensor within its enclosure. Controllers with integral sensing elements are available that sense pressure, differential pressure, temperature, and level. Some controller designs have the set point adjustment knob in the controller, making set point adjustment a local and manual operation. Other types receive a set point from a remotely located pneumatic source, such as a manual air set regulator or another controller, to achieve set point adjustment. There are versions of the pneumatic controller that support the useful one-, two-, and three-mode combinations of proportional, integral, and derivative actions. Other options include auto/manual transfer stations, antireset windup circuitry, on/off control, and process-variable and set point indicators. 

Proportional-plus- integral-plus-derivative Any Large Fast Batch control processes with sudden upsets temperature control... 

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