Input signals to MoVS

[Mefi01]

Dear all,

I would like to control motorised operated valves using PLC which is in turn is triggered by a manual switch . I’m now adding a scada system and want to be able to trigger both the PLC using the manual switch and the scada ( simply by triggering a digital input signal ‘1’). What are your suggestions for achieving this and how can I interlock these two modes

 

[xnuke]

Parallel structure, one branch with a NO SCADA direction contact and a NO Remote contact, the other with a NO Manual direction contact and a NC Remote contact, and an output to drive the valve in the desired direction. Repeat on another rung with SCADA and Manual contacts for the opposite direction.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[itsmoked]

Do you have some sort of input from the valve feeding back OPEN or CLOSED?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Mefi01]

xnuke , Thank for your response. Please provide a schematic if possible ?
itsmoked, yes but these are not important, I just need to trigger the MOVs without caring too much about the monitoring signals

 

[xnuke]

itsmoked was pointing out that you will need commands on the rungs I described to shut off the output when the respective limits are reached, so yes, these are important. You may also need other interlocks to prevent trying to move the valve in opposite directions simultaneously. You didn't ask about such things, so I didn't post about them. Please try to sketch the logic yourself and post it. People will give you feedback. We give tips; we don't do the work for you.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.