Isolater Frequently Asked Questions Answers

Analog signal isolator applications?

It can be used in all industrial applications that require electronic measurement and control - such as in process control power plants, metallurgical plants, water and wastewater treatment plants, oil and gas production plants, and chemical production plants. In fact, analog signal isolators are used in the continuous or batch production process where it is necessary to measure and control various physical quantities such as temperature, pressure, liquid level, flow, weight, and speed. These physical quantity parameters are accurately measured and, despite being affected by external factors such as the atmosphere and installation, it must be ensured that the process transmitted from the site to the control room is not reduced or disturbed. Converting or transmitting these signals requires high-quality electronic systems that can adapt to or withstand harsh environments such as temperature variations, electromagnetic interference, vibration, corrosion, or explosion.

What functions can analog signal isolator provide?

One or more of the following:

1. High reliability isolation of DC measurement and control signals.

2. Convert various non-standard signals to standard signals, such as 0...5V input, 4...20mA output.

3. Amplify, linearize, and convert a small signal from the sensor input, such as a thermocouple mV signal, into a large current signal output so that it can transmit distances of several hundred meters or even kilometers.

4. The relay contact alarm signal is generated through the analog input signal to complete the status monitoring and alarm.

Why do you need separate analog signal isolators today? It is clear that the control systems (PLC and DCS) can perform some of the same functions.

1. This is a fact to some extent. However, we have noticed that these field devices (transmitters, sensors, valves, and actuators) are transported through cables to various places. Usually they go directly to the control room, but there are also many signals to be transmitted to the local display and alarms. And they need to be isolated from each other.

2. Many sensors—such as thermocouple temperature sensors—are often required to be isolated, converted, and linearized in-situ and converted to standard high-current signals (eg, 4...20 mA) to accommodate long-distance transmissions—which can replace expensive thermoelectrics. Even compensation wire is transmitted to the control room.

3. If the control system itself does not have an analog input card with isolated functions, it must also be isolated by an independent signal isolator at this time.

4. The isolator can do this very easily when the control system cannot supply power to the sensor/transmitter.

5. If it is independent of the control system display, a highly integrated split-screen display is required, which can be easily achieved with an input/output signal splitter.

6. When the plant operator needs to linearize the signal in situ—a material volume indicator is required to inject the material storage tank, but the measured signal is a level signal (the level is converted to volume depending on the tank Specific structure and shape).

7. The control system needs to only receive 4...20mA analog signal input, but the sensor provides other unconventional signals, such as 0...20mV, 2...10V, 0...10kΩ, 0.. .1mA, 4...12KHz, 0...5Aac, and so on.

8. When the control system needs to be reliably isolated from the electronic noise pulses superimposed on the analog input signal, the isolator can isolate it safely and reliably.

9. When the increase of the analog input signal means that a new and expensive control system I/O card is needed, a cost-effective isolator can be easily expanded.