Signal transmission distance for three-wire thermistor systems
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What is the signal transmission distance for a 1.5-wire diameter thermistor in three-wire configuration? What is the signal transmission distance for a 2.5-wire diameter thermistor in three-wire configuration? If anyone knows, please share. What standards to use?
For three-wire heating resistors, the effect of wire resistance need not be considered, right?
Although three-wire and four-wire systems are designed to eliminate the resistance in the wires, this is theoretically feasible provided that the resistances of the three or four wires are exactly the same; in practice, however, this is very difficult to achieve. Therefore, I recommend using a temperature-sensitive sensor when the distance is too great, as it saves money while still ensuring accuracy
Using temperature control is of course a good option, but some homeowners don’t like it. It is said online that a single cable can be used as long as its resistance is less than 5 ohms, which corresponds to a length of around 440 meters. Is such a requirement in place? I searched for a long time but couldn’t find the standard. Those who have used it, please share your experiences.
We have a set of devices here, 600 to 700 meters away from the control room, and the thermal resistors are working properly.
The distance between the wires used for measuring a three-wire thermal resistor is related to the input impedance of the accompanying instrument; the higher the internal resistance, the greater the allowable distance. It turns out that there are regulations for dynamic coil displays, requiring all 3 wires to have a resistance of 2.5 ohms. However, modern digital display instruments, due to their high input impedance, no longer have specific requirements regarding the resistance of the wires; it is only necessary that the resistances of the three wires be equal in order to eliminate lead-related errors. If the distance between the wires is too long, factors such as interference and changes in ambient temperature may need to be taken into consideration.