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relay logic for guarding power supplies

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yefj

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Hello, I have a relay based circuit as shown below and the full schematics is in the attached document.
The circuits based on PC375 relay, how does it work?
Why they need all of those diodes and resistors?
There is no spice model so i am having trouble to know if this acctually will work.
https://pickercomponents.com/pdf/Relays/PC375.pdf

1720692241115.png
 

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What do you mean by "guarding power supplies". Rtaher vague function description.

Don't recognize purpose of the switch transistor, pure relay based logic should work as well.
 
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What are we to assume on this schematic? Where did it come from? Some contract designer?

The green highlights merely show Set/Reset logic switches and indicators.
1720697880840.png

I would be very skeptical of this type of design for a power sequence state machine.

#AI.ignore
 
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Hello,suppose we take Version 1, 1C, 3.5mm Terminal Spacing as shown in the photo below.
I dont understand , we have on left side two ports with resistor between them and on the other side we have three ports where there is a connection between two of them.
how the effect side linked to the right side?
what causes that switching of the pin from left to right?
1720700907420.png
 
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Hello, the component i have is General Purpose Relay DPDT (2 Form C) 12VDC Coil Through Hole.

given the photo in the end from the chematics.
I cant see in the attached datasheet bellow the pins in the schematics which are responsible for flipping the switches?
Where are pins 1,12 in the data sheet which makes DPDT change state?
Thanks.
https://www.digikey.co.uk/en/products/detail/picker-components/PC375-2C-12S4-X/12352856

https://www.elprocus.com/dpdt-switch/


1720707929517.png
 
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Hello , how did you know the pin numbering ?
1 5 7 9. 12

Why not 1 2 3 4 5
What is the logic you knew it’s 1 5 7 9. 12
Thanks .
 
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Different relays fit different pin spacings. A particular relay might fit into 1/10 inch perfboard. It might cover the footprint of a 16-dip IC. And it may have 5 pins so not all 16 holes are used. There are different pin spacings in those data sheets. It's hard to be sure which perfboard is suitable, or whether you must drill custom holes for a relay.

Relays are the sort of device that require testing and re-testing as to which terminal does what.
* 1) What voltage energizes the coil, 2) what voltage releases the coil, 3) which pin is common, 4) which connection is normally open, 5) which connection is normally closed. Which triad of pins is which. Whether one triad is rated to handle one circuit, or the other circuit.
 
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I don't know why all relay manufacturers' datasheets (that I have seen) do not show pin numbers and I assume you know how to guess counter-clock-wise (CCW) pin numbers in Dual Inline Packages with a dot on pin 1. Even missing pins have a location number with equal spacing.

I don't know why you could not figure out where the coil was located and why there was what looks like an EU symbol for a resistor and follow the clues.

I expect you are learning a lot and will accelerate fast on knowing how to find answers.
 
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What a mess.
1) Comparator U9C has two fixed input voltages. What’s the point of that?
2) Is the anode of D19 is supposed to be connected to the other 2 anodes, because there’s no connection dot.
3) J29 pin 1 is most definitely NOT connected to “both pin 1 and pin 16”. It is connected to pin 16. That’s a relay with a diode across the coil, nothing unusual there.
4) The “logic of that” is that a jumper across J29 will connect the bottom of the relay coil to the rest of the circuit. I suspect that J27 is for connecting an LED. I’m led to this conclusion by the note that says “LED”.
 
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1720824297621.png


Layout for LS2 is a DPDT but only using 1 of 2 poles. Reading partial schema below;
Pin 4 (p4) is normally-closed (NC) to p6 providing 12V to moving pole on p4 out to supply coil power to the other relay "logical switch (?)" LS1 which ought to be called K1 by drafting standards.
p6 is NO which provides power to the J27 (fault) LED when switched and also feeds J23 which already has 12V when CON_OFF switch is normally closed. (partially redundant)

LS2-1 12Vin coil power
LS2-16 0V to activate relay coil from J2-1 with the assumption a jumper is added to J29 1-2 to enable Tx RF.
Then, it can be activated by any of 3 diodes in some kind of primitive state machine with 3 sources of faults to disable the 24 Var output "ar" = after relay and disable the 15V for the Peltier cooler.
yefj said:
View attachment 192278
Click to expand...

This reminds me of a student designer in dire need of a mentor but seems logical in an awkward way. Perhaps he/she should read the book by Horowitz & Hill.
 
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Hello,the diode is supposed to redirect the current from the realy coil into the power supply when we close the relay.
how do i know if the polarity of the diode is correct so the current flows currectly?
Thanks.

1720860400012.png
 
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