FAQs on instrument cable issues; feel free to ask if you have any questions
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This post was last edited by Wang Tianze on 2016-11-8 at 20:12. The theory isn’t as complex as everyone thinks. But I have more practice than everyone else. If you have any issues with cable meters, feel free to reach out to me
May I ask: 1. In 485 communication, the communication devices at both ends are prone to damage during thunderstorms; could the cable be a factor? 2. For the DCS terminals, do you prefer flexible cables or rigid cables? Why? 3. For VV power cables, after being in use for several years or even a decade or so, occasional phase-to-phase short circuits occur. What do you think are the reasons for this? How to check and avoid it? Do you think power cables should be replaced after xx years of operation? With factors such as varying cable qualities, different selection options, varied methods of installation and maintenance, and differences in climate across different regions, how can this be handled?
1. Is there really such a thing as an intrinsically safe cable, or would it be better to call it a cable for intrinsically safe circuits? 2. Are there any insulation requirements between the cable’s armor layer and shielding layers, as well as between the overall shielding layer and the individual shielding layers? 3. Are there different requirements for the material of the signal cable’s shielding layer depending on various interference conditions, such as different interference frequencies or different types of interference fields? 4. Generally, the typical resistance value at 20 degrees Celsius is used to calculate the voltage drop in cable circuits. Are there more detailed resistance values available, such as analyses of how the typical resistance value of signal cables changes with temperature, soil conditions, and installation methods? Could an expert please help answer this? Thank you!