24V Relay circuit design

Barton Bennett said:

need to Isolate it

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danadakk said:

When you say ISO do you mean simple on / off switching of the power pack
or real true "galvanic" isolation ?

https://www.monolithicpower.com/en/learning/mpscholar/isolation-solutions/intro-to-digital-isolation/of-isolation-techniques

Same question for sensors ?

If just switching power then one relay for powerpack with appropriate current and voltage ratings,
and for sensors just small signal relays as their V and I typically quite low.


Regards, Dana.

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Barton Bennett said:

all 4 sensors need to be activated and the in-cab isolator switched on before the powerpack will switch on.

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KlausST said:

Hi,

I have no idea what the situation is and what the question is.
A sketch - as always - tells more than a lot of words.
Does

mean "isolation" in an electrical manner?

Also you say "optical sensor" .... I don´t get it. Do you mean the linked sensor .. but it is in no way an "optical" one. Or are there other sensors.
I´m really lost.

Klaus

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BradtheRad said:

The type of sensor is ambiguous. Have all types been tested (optical type versus inductive type)?.

There's the spec page calling the sensor inductive, normally Open and output type is PNP. Each sensor appears made to mount in a hole in the chassis (metal common ground of the vehicle). Conceivably a craftsman could custom-make a jig for mounting sensors exactly where each can do a proper job.

My reply was almost poised to recommend wiring all sensors in series and with any other switch. This one wire goes through the coil of your relay. However it may take extra work to wire the sensors in series. In any case all sensors' output wires (and other switch) ought to be assembled into some kind of logical 'AND' gate. Voltages must be compatible.

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BradtheRad said:

The type of sensor is ambiguous. Have all types been tested (optical type versus inductive type)?.

There's the spec page calling the sensor inductive, normally Open and output type is PNP. Each sensor appears made to mount in a hole in the chassis (metal common ground of the vehicle). Conceivably a craftsman could custom-make a jig for mounting sensors exactly where each can do a proper job.

My reply was almost poised to recommend wiring all sensors in series and with any other switch. This one wire goes through the coil of your relay. However it may take extra work to wire the sensors in series. In any case all sensors' output wires (and other switch) ought to be assembled into some kind of logical 'AND' gate. Voltages must be compatible.

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Barton Bennett said:

Hello Brad, the extra wiring isnt a big issue, does this mean it is feasible to wire all 4 of these sensors in series together with the switch, to 1 x 24V relay in order to supply power tot he powerpack?

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BradtheRad said:

Yes, if you're lucky four sensors in series have little resistance and can pass sufficient voltage-current to energize your relay coil. Although the load-carrying contacts may be 24V rated, the coil contacts can have a different voltage range of activation.

Already several questions pop up. For one, detail of the twist lock mechanism. Example... size, easiest method to distinguish an unlocked mechanism. The cost at the inductive sensor link appears high, yet the mechanism might not even be massive enough to trigger the sensor. The sensor itself appears large and suited to detect a door.

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