Switch question
Switch question
(OP)
Hi,
We have a control panel which contains a plc. The panel provider is not providing a pressure switch but they have 3 terminals +, sw,- . The sw terminal is input into the Plc. The plus is providing 24V and the - is ov
My question is can we use a change over contact type switch with common, no ,nc terminals on the arrangement they have provided?
Thanks
We have a control panel which contains a plc. The panel provider is not providing a pressure switch but they have 3 terminals +, sw,- . The sw terminal is input into the Plc. The plus is providing 24V and the - is ov
My question is can we use a change over contact type switch with common, no ,nc terminals on the arrangement they have provided?
Thanks





RE: Switch question
Now YOU will have to decide based on your preferences, and if you have none, you will get numerous opinions of which way to go... let the battle commence!
"Will work for (the memory of) salami"
RE: Switch question
RE: Switch question
Job security for me OperaHouse, locating/replacing is what I do. But sink or source, I'm thinking 6 to 1 half a dozen to another, does it really matter?
RE: Switch question
Pls ignore.
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Switch question
I think this is a bit of an overstatement. There must be millions of switches out there serving as PLC inputs. Somehow the large majority of them continue to function. The contact oxidation and corrosion can be largely overcome by 1)using high quality switches suitable for their service and 2)using a high enough wetting voltage to punch through any oxidation. In power plants and other critical facilities, 125 V dc is commonly used for wetting voltage and this helps tremendously. It is more of any issue when 12 V or 24 V is used as the wetting voltage.
The contact oxidation can be an issue, but it's only one of many.
RE: Switch question
Lc85; It appears no one has answered your question.
Yes. You can use any switch you want since you have more than 10V involved. To use a normally open switch hook it from your given "+" terminal to the "SW" terminal.
FYI the setup they've given you is to use something like an optical switch where it's an active electronic device. You'd feed it the power it needs to function by hooking it's "+" and "-" terminals up to the PLC ones you've listed, then the electronic switch's output to the PLC "sw" input.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Switch question
RE: Switch question
You can't just hook the switch up either way (sourcing or sinking) unless you also switch the logic inside the PLC.