Pressure transducers are devices that convert the mechanical force of applied pressure into electrical energy. This electrical energy becomes a signal output that is linear and proportional to the applied pressure. Pressure transducers are very similar to pressure sensors and transmitters. In fact, transducers and transmitters are nearly synonymous. The difference between them is the kind of electrical signal each sends. A transducer sends a signal in volts (V) or millivolt per volt (mV/V), and a transmitter sends signals in milliamps (mA).
Both transmitters and transducers convert energy from one form to another and give an output signal. This signal goes to any device that interprets and uses it to display, record or alter the pressure in the system. These receiving devices include computers, digital panel meters, chart recorders and programmable logic controllers. There are a wide variety of industries that use pressure transducers and transmitters for various applications. These include, but are not limited to, medical, air flow management, factory automation, HVAC and refrigeration, compressors and hydraulics, aerospace and automotive.
There are important things to consider when deciding what kind of pressure transducer to choose. The first consideration is the kind of connector needed to physically connect the transducer to a system. There are many kinds of connectors for different uses, including bulletnose and submersible connectors, which have unique applications. Another important part is the internal circuitry of the transducer unit, which is housed by a "can" that provides protection and isolates the electronics. This can be made of stainless steel or a blend of composite materials and stainless steel. The various degrees of protection extend from nearly no protection (an open circuit board) to a can that is completely submersible in water. Other kinds of enclosures safeguard the unit in hazardous areas from explosions and other dangers.
The next thing to consider is the sensor, which is the actual component that does the work of converting the physical energy to electrical energy. The component that alters the signal from the sensor and makes it suitable for output is called the signal conditioning circuitry. The internal circuitry must be resistant to harmful external energy like radio frequency interference, electromagnetic interference and electrostatic discharge. These kinds of interferences can cause incorrect readings, and are generally to be avoided when doing readings. Overall, pressure transducers are well-performing and high-accuracy devices that make life easier for many industries.
The next thing to consider is the sensor, which is the actual component that does the work of converting the physical energy to electrical energy. The component that alters the signal from the sensor and makes it suitable for output is called the signal conditioning circuitry. The internal circuitry must be resistant to harmful external energy like radio frequency interference, electromagnetic interference and electrostatic discharge. These kinds of interferences can cause incorrect readings, and are generally to be avoided when doing readings. Overall, pressure transducers are well-performing and high-accuracy devices that make life easier for many industries.
What are Pressure Controllers?
Pressure controllers are used to regulate positive or negative (vacuum) pressure. They receive pressure sensor inputs, provide control functions, and output control signals. Pressure controllers use several control types. Limit controls protect personnel and equipment by interrupting power through a load circuit when pressure exceeds or falls below a set point.
Advanced controls use non-linear control strategies such as adaptive gain, dead-time compensation, and feed-forward control. Linear controls use proportional, integral and derivative (PID) control; proportional and integral (PI) control; proportional and derivative (PD) control; or proportional (P) control. PID control uses an intelligent input/output (I/O) module or program instruction for automatic closed-loop operation. PI control integrates error signaling for steady-state or offset errors. By contrast, PD control differentiates error signals to derive the rate of change. PD control increases the speed of controller response, but can be noisy and decrease system stability.
Advanced controls use non-linear control strategies such as adaptive gain, dead-time compensation, and feed-forward control. Linear controls use proportional, integral and derivative (PID) control; proportional and integral (PI) control; proportional and derivative (PD) control; or proportional (P) control. PID control uses an intelligent input/output (I/O) module or program instruction for automatic closed-loop operation. PI control integrates error signaling for steady-state or offset errors. By contrast, PD control differentiates error signals to derive the rate of change. PD control increases the speed of controller response, but can be noisy and decrease system stability.
Pressure controllers differ in terms of performance specifications, control channels, control signal outputs, and sensor excitation supply. Performance specifications include adjustable dead-band or hysteresis, minimum and maximum set points, update rate or bandwidth, and percentage accuracy. Hysteresis or switching differential is the range through which an input can be changed without causing an observable response. Hysteresis is usually set around the minimum and maximum end points. Control channel specifications for pressure controllers include the number of inputs, outputs, and feedback loops. Multi-function controllers and devices with multiple, linked looped are commonly available. Control signal outputs include analog voltages, current loops, and switched outputs. Some controllers power sensors with voltage levels such as 0 5 V or 0 10 mV. Others power sensors with current loops such as 0 20 mA, 4 20 mA, or 10 50 mA.
Selecting pressure controllers requires an analysis of discrete I/O specifications, user interface options, and special features. Devices differ in terms of the total number of inputs, total number of outputs, and total number of discrete or digital channels. Some pressure controllers provide alarm outputs or are designed to handle high power. Others are compatible with transistor-transistor logic (TTL). Analog user interfaces provide inputs such as potentiometers, dials and switches. Digital user interfaces are set up or programmed with a digital keypad or menus. Pressure controllers with a graphical or video display are commonly available. Devices that include an integral chart recorder can plot data on a strip chart, in a circular pattern, or on a video display. Special features for pressure controllers include self-tuning, programmable set points, signal computation or filters, and built-in alarms or indicators.
Selecting pressure controllers requires an analysis of discrete I/O specifications, user interface options, and special features. Devices differ in terms of the total number of inputs, total number of outputs, and total number of discrete or digital channels. Some pressure controllers provide alarm outputs or are designed to handle high power. Others are compatible with transistor-transistor logic (TTL). Analog user interfaces provide inputs such as potentiometers, dials and switches. Digital user interfaces are set up or programmed with a digital keypad or menus. Pressure controllers with a graphical or video display are commonly available. Devices that include an integral chart recorder can plot data on a strip chart, in a circular pattern, or on a video display. Special features for pressure controllers include self-tuning, programmable set points, signal computation or filters, and built-in alarms or indicators.
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