Regarding valve control
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I’d like to ask everyone: for a three-way valve on-site, how many cables are required to enable flow path switching? Two or one? Does it depend on whether the valve is of the dual-control type or the spring-return type when checking it? Are there two implementation methods: software switches and hardware switches? Software switch: Connects to the PLC’s DO points. Hardware switch: No PLC is involved; it is connected via direct wiring to a physical switch for manual control. I’m not sure if my expression is correct.
The description is a bit chaotic! You just need to describe your equipment properly, for example, whether this three-way valve is used for regulation or for shutting off flow. How do you want to control it? Do you want remote control or local control? Can it still be controlled manually from a distance?
Used for cutting and direction reversal; manual control is desired from an PLC cabinet on-site
I mean, does a three-way valve require a 2/3-way solenoid valve or a 2/5-way one? A 2/3-way valve uses one cable, while a 2/5-way valve requires dual control and thus two cables.
This post was last edited by liuyuqian on 2017-4-7 at 17:39. A three-way valve for cutting, a double-acting cylinder, a two-position five-way solenoid valve, and a cable are sufficient to meet the control requirements you have. Solenoids like this can be controlled with just one DO output from the PLC.
Is it necessary to manually control the direction of the valve on-site? Is it not required to use a PLC – just connecting a toggle switch will suffice?
Do you need both on-site control and remote control?
For on-site control by process operators, remote control is not allowed
Is the actuator of your three-way valve single-acting or double-acting? Is the fault state on, off, or maintained? A two-way three-port connector indeed uses one wire, but a two-way five-port connector may use either one or two wires.
It doesn’t need to be connected to the PLC; instead, we just use an empty space on the PLC cabinet to install a manual switch. If we want to allow flow through the valve, we simply rotate the manual switch accordingly. I’d like to ask everyone for advice on how to choose such a manual switch
As for how many wires are needed, that depends on the specific situation. For example, if control is to be done using a dual-control solenoid valve, then 2 pairs of wires are required. If automatic control is desired, then a PLC or DCS is necessary