【Daily Question 20090414】Let’s discuss what types of signals are used for analog input in control systems (simple question)
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Please discuss what types of analog input signals exist in control systems and what their range is. You may refer to the characteristics of the AI module in your own systems. We hope that everyone will organize their thoughts freely and participate actively, with valuable insights from those who take part in the discussion being highly rewarded. Encourage originality. This post was last edited by wopale3 on 2009-4-14 at 14:47.]
Common analog input signals include: the resistance signal from thermal resistors (RTD), the mV signal from thermocouples (TC), 1–10V voltage signals, and 4–20mA current signals (with some also using 0–20mA). However, voltage signals are usually converted into current signals before being fed into the card. Common signals used to input into current signal cards include flow rate, pressure, liquid level, current, gas content,...
The AI elements in the system are focused on the following instrument signals: flow rate signals – differential pressure transmitters, vortex flow meters, electromagnetic flow meters, mass flow meters, rotameters, ultrasonic flow meters, and so on. Pressure signals: such as pressure transmitters (including gauge pressure transmitters)……etc. Level signals: ultrasonic level gauges, magnetostrictive level gauges, radar level gauges, servo level gauges)……etc. Temperature signals: integrated temperature transmitters)……etc
Common analog input signals include: RTD (thermal resistor), mV (thermocouple), and mA (4-20mA current). Some use integrated temperature transmitters, which reduce the analog input signals of DCS to just one type: 4-20mA.
Common analog input signals include: transmitter 4–20mA signals, thermal resistors RTD, thermocouples TC, and encoder pulse signals.
In addition to what the others have mentioned, the most commonly used type is the AI signal with HART protocol, which is required in AMS systems. Additionally, the RS485 interface is the most commonly used for communication signals; a large number of PLCs and DCS systems utilize this interface for communication, and it can be configured in a redundant manner. Additionally, some transmitters from certain companies are now available in wireless versions, which use wireless transmission to send signals to the DCS system; these are currently used in small, simple devices to a limited extent.
Common analog input signals include: Temperature: resistance signals from thermistors (RTD), and mV signals from thermocouples (TC). Pressure, flow rate, level, and rotational speed. Current: 1-10V voltage signals and 4-20mA current signals (with some also using 0-20mA). Displacement, flow rate, rotational speed, frequency
The AI elements in the system are focused on the following instrument signals: flow rate signals – differential pressure transmitters, vortex flow meters, electromagnetic flow meters, mass flow meters, rotameters, ultrasonic flow meters, and so on. Pressure signals: such as pressure transmitters (including gauge pressure transmitters)……etc. Level signals: ultrasonic level gauges, magnetostrictive level gauges, radar level gauges, servo level gauges)……etc. Temperature signals: integrated temperature transmitters)……etc
What I have come into contact with includes the outputs of pressure transmitters, flow signals, temperature transmitter signals, level gauges, and so on.
Please discuss what types of analog input signals exist in control systems and what their range is. You may refer to the characteristics of the AI module in your own system. I. Types of analog input signals 1. Thermal resistors (RTD): Thermal resistor signals； 2. mV signal of the thermocouple (TC) ； 3, 4-20mADC two-wire current signal ； 4. 4-20mADC active current signal ； 5. DC voltage signal ； 6. Pulse frequency signal. II. What is the range? What kind of range does the poster mean? Regardless of the type of analog signal, after I/O conversion, its range becomes 4-20 mA DC ； The range is always 16 mADC. The range values and units corresponding to the different variables for 4–20 mADC and 16 mADC are displayed or controlled on the DCS.