Seek proximity switches of the dry-contact type for on-off valves
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For the selection of on/off valves, the requirement for valve position indication is a valve position feedback switch of the “pro*mate limit” type. However, I do not want to use NAMUR cards on the DCS side; instead, I would like to use ordinary DI cards just like those used with other dry contacts. I would like to ask whether there are any proximity switches available for dry contacts, along with recommended models or samples. Thank you!
Many valve position switches use dry contact switches.
A proximity switch is of the transistor type; there is no such thing as a dry contact. For it to function, power must be supplied to it. If you don’t want to use a NAMUR-type switch, you can use a 24V proximity switch
Just choose a dry contact switch (not a proximity switch) to make things simpler with a standard DI card.
Hello, does the 24V proximity switch use a regular DI card in conjunction with the DCS? Is this 24V the detection voltage for DI? Two-core wire for cables? Thank you!
The valve indicator on my end uses microswitches, which are connected directly to the control DI card, which is quite convenient.
Then it’s better for you to check the operating voltage of the DI card; generally, 24V is the standard operating voltage
Many valve position switches use dry contact switches
Could you tell me, are the signals dry contacts?