Does a cut-off valve with fault holding function require 1 DO or 2 DOs?
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The cut-off valve with FL fault mode has two solenoids; does this also require 2 DO points?
One DO should be sufficient; the two solenoids are controlled by the same DO signal.
How should the wires be connected on the card that shares one DO?
This post was last edited by “Hasty Passerby” on 2017-10-31 at 17:04. We used relays to isolate the field solenoid valves; these relays in the SIS system were connected to two normally open contacts respectively. Of course, using two DOs is also fine.
Of course it’s two DOs; there’s no need to hesitate.
This post was last edited by lc13147735 on 2017-11-2 at 16:22. 1. If there are two solenoids, it should be a dual-electronic control system; the two cylinders do not have spring reversion, so two DO points are necessary. 2. One solenoid valve is controlled by a single signal; when the solenoid valve is closed, air is trapped inside the cylinder, which also helps to maintain the position – 1 DO point. In short, I think both solenoids are definitely dual-control types, and the cylinders don’t have spring reversion.
This post was last edited by zqwqiwu123 on 2017-11-2 at 16:52. First of all, FL must be dual-control, so it must output two DOs.
It should be 2 DOs; you need to check the specific control of these two solenoid valves
It mainly depends on what kind of solenoid valve you have, and then you decide on the number of DOs.
2 solenoids require 2 DOs; using one DO to drive a relay with two pairs of contacts is a approach that requires caution, as both availability and safety must be taken into account. The FL type can be implemented with the valve itself; it has nothing to do with the number of solenoids used. The inclusion of 2 solenoids is likely intended to prevent accidental operation. The original poster should provide specific images for a better analysis.
A DO point would work too; the cylinder doesn’t have a spring for reset, so a two-position five-way solenoid valve is used