Maybe, but I'm not familiar with that specific term. Can you tell me what you think it does. It sounds a bit like what we called a 'sealing contact'. It is often used in ladder logic controls and nowadays in PLC control which has largely replaced relays, but still uses the ladder logic paradigm.Hey, can anyone describe the operation and use of a stop/start/retain relay control circuit for an AC or DC machine?
See reply in #5 , standard N.O. retaining contact across the start P.B.Stop and start are clear, it is the "retain" that is the puzzle. And I am also aware of the Run/Jog arrangement. .
Or is it possible that the TS is referencing the sealed Start function as "Retain"???
My start/stop circuits self-identify as "latching" circuits and they demand this discussion be more inclusive.I know it as Retaing contact rather than "sealed"
That is what triggered my original response, the meaning of 'sealed' and 'retained' was just too close to be coincidental. I learned ladder logic and PLC's in the Detroit area from auto industry professionals moonlighting at the local Community College (I attended the Community College two decades after getting a Master's Degree in EE). It might be a 'local' thing.See reply in #5 , standard N.O. retaining contact across the start P.B.
I know it as Retaing contact rather than "sealed"
I propose bring all these different-name-for-the-same-thing...things, under one umbrella, unified by a single term. It has to be something new, so nobody gets offended that someone else's local term was chosen and theirs wasn't. I vote, eh, let's see... "bound and gagged contacts."Sealed, Latched, Retained, all depends where you got your training probably!
Fairly obvious by the descriptive similarity I would say ?
What is this in response to? Are you arguing against the use of maintained e-stops under the premise that machinery will automatically restart if power is lost? That seems incongruous with your previous statement and leaves me puzzled.A retained contact stays in whichever state it held prior to a power interruption. So it is suitable for lighting systems. Every machine specification demands that it NOT restart after a power interruption. Hence my puzzlement. After an E-STOP shutoff, when the button was pulled back out, only the PLC processor, on systems that used a PLC or injection controller, and position indication lights were allowed to switch on. No automatic restarts were allowed.
My application of "E-Stop" buttons is that they always used a maintained position button, while a stop button was only a momentary opening of the circuit. The intent was that it would always take two steps to start after an "E-Stop" shutoff. At least two auto companies specified that for the machines and equipment that we provided.
You are under a misapprehension as to my meaning as outlined in the page 6 circuit I referred to in the Schneider book.A retained contact stays in whichever state it held prior to a power interruption. So it is suitable for lighting systems. Every machine specification demands that it NOT restart after a power interruption. Hence my puzzlement. After an E-STOP shutoff, when the button was pulled back out, only the PLC processor, on systems that used a PLC or injection controller, and position indication lights were allowed to switch on. No automatic restarts were allowed.
That sounds a bit on the kinky side. Are you sure that's a good idea?I propose bring all these different-name-for-the-same-thing...things, under one umbrella, unified by a single term. It has to be something new, so nobody gets offended that someone else's local term was chosen and theirs wasn't. I vote, eh, let's see... "bound and gagged contacts."
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