Instrument cable selection
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Why are two cables, KVVP 3x1.0 and KVVP 5x1.0, connected to the control valve? What determines the choice between 3-core and 5-core cables? And what type of cable should be used for the solenoid valve?
It’s probably used to connect to the limit switch. The solenoid valve can be connected to KVVP or KVV.
Check your power supply standards and signal standards. There is also the principle of whether power cables and signal cables should be shared
I remember that the instrument cables used in my company were all of the DJ-GPRF46 specification.
For the control cables of instruments, KVVP is used; the number of cores chosen depends on the signal type of the instrument – for example, thermocouples naturally require 3 cores. Flow meters generally also use a 2-core design, and control valves likewise often employ a 2-core design. For electrical cables, KVV can be chosen; they are usually 2-core, and solenoid valves also often use KVV 2-core cables.
For control valves, the signal is an analog signal, and I usually use the DJYPVR‑1×2×1.0 cable. If the valve is equipped with limit switches for the switch position, a KVVRP‑4×1.0 cable can be connected separately. KVVR-2×1.0 is sufficient for solenoid valves. As for the two cables mentioned by the original poster, it is estimated that one is for the valve signal and the other is a limit switch for the switch position.
I would like to ask: why are three-wire thermocouples used?
The electrical accessories commonly found on control valves include valve positioners, solenoid valves, limit switches, position transmitters, etc. The more accessories a valve has, the more cable cores it will require. If it is a computer-controlled valve, shielded cables such as KVVP, KVVRP, DJYPVR, etc. should be used.
Thermocouples use compensation wires, while 3-wire thermistors are used to compensate for the resistance of the wiring.
The wire connected to the solenoid valve is a power supply wire; per the specifications, its cross-sectional area should be no less than 1.5 mm2
For the power and control cables of control valves, it is necessary to consider whether they are susceptible to external signal interference. In KVVP, the letter P stands for shielding. Power cables are equipped with shielding to ensure that the transmission of other signal wires is not affected during power supply, while control cables use shielding to prevent external signals from interfering with them. The number of cores in the cable depends on the control requirements of the control valve; a case-by-case analysis is required. This post was last edited by liuyuqian on 2008-1-19 00:17.]
For control valves, the cables KVVP3X1.0 and KVVP5X1.0 can be used; 3x1.0 is suitable for the input signal of the valve positioner, while 5x1.0 is used for the signals from the two valve position switches. For solenoid valves, cables KVV2X1.5 or 3X1.5 can be chosen.
I think the poster is referring to a two-position switch valve; ‘Sanxin’ means dual electric control, while a five-core version includes a feedback signal.
Generally speaking, a 2-core cable is sufficient for pneumatic control valves; what the poster is referring to is probably electric control valves.