A basic issue with the instrument
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This post was last edited by wwxxss_1 on 2009-12-18 at 13:10. Does the valve positioner of a pneumatic control valve regulate the valve opening, or does it transmit information about the valve opening to the control room?
Traditional I/P positioners only have the function of adjusting valves, while modern smart I/P positioners can both adjust valves and provide feedback on their opening degree.
It should serve to transmit data
Positioners are used to achieve precise positioning of valves, and it is the valve position transmitter that sends the valve position to the control room. 1# wenfeng325
A valve positioner is used to adjust the opening degree of a valve; the control room sends a 4-20mA signal to regulate the valve position. If it is necessary to transmit this information to the control room, a valve position transmitter is required. Under normal circumstances, the valve position can also be determined based on the 4-20mA signal
A valve positioner is used in the control room to adjust the valve opening degree via 4-20mA signals; if the control room needs to know the valve position, a valve position transmitter should be added. Under normal circumstances, the 4-20mA signal serving as the setpoint is sufficient to determine the valve position
Current conventional valve positioners are used to precisely control the opening degree of valves. If it is necessary to transmit this opening degree to the control room, a valve position transmitter must be installed. However, intelligent valve positioners such as FF bus valve positioners can not only precisely control the valve position but also transmit it to the control room.
Ordinary valve positioners are used to precisely control the opening degree of valves; they do not have a valve position feedback function. A feedback switch is generally installed to determine the valve position
The function of the positioner is to receive the standard current signal from the regulator, convert it electrically, and then output a pneumatic pressure signal that corresponds one-to-one with the current signal, which is subsequently sent to the diaphragm of the control valve. In fact, it is the controller in the DCS that issues the control commands; the positioner is responsible for performing calculations, while the actuator carries out the actual actions. If you want to see the exact valve position in the DCS, you can install a valve position feedback device.