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we are looking for relay that can detect millisecond power loss and triger dry contact state from On to Off and remember the state until the next millisecond power loss
the ideal device would:
Be powered continuously by 24 VDC.
Detect the brief loss of power.
Internally generate the trigger pulse.
Toggle and remember its output state.
Provide a dry contact output.
The challenge with our exact application
Most impulse relays expect:
1 OFF → ON pulse → OFF
You have:
1 ON for hours → OFF briefly → ON for hours
That’s an unusual control method.
If you have any relay product that fits into this category please let us know
Hello chirag.kathiriya,
The information you are looking for would possibly be on a datasheet but is not searchable on our website. From your bullet points this isn’t a relay but a full control unit you will be looking for. I don’t have a part to offer for this.
I have concerns that are unanswerable without further information:
Electrotechnical relays are slow. You may have better results if you shift to a solid-state relay.
Power supplies are slow. Assuming you are using a line-powered +24 VDC supply, there is considerable output capacitance that will allow the load to ride through minor power dips.
All of this depends on the duration of the power glitch that you are attempting to identify. @Quinn_2289 make a good point about needing more than just a relay.
Looking forward to the conversation.
Sincerely,
APDahlen
P.S. Here is an article that explores the transients response of a representative +24 VDC supply.
We are supplying a constant 24VDC power input to the controller. The controller has a dry contact output that is used to turn another system ON and OFF. However, the 24VDC supply remains continuously available in all operating conditions.
Our requirement is to simulate a brief power loss (for a few milliseconds) from an relay from out side. The other relay that’s connected to that power source should detect the same and trigger the dry contact to change the state (ON/OFF).
We are exploring relay solutions or other devices that can create a controlled millisecond-level interruption in the 24VDC supply. We would like to know if you have a recommended relay or circuit that can:
Generate a short-duration power interruption (milliseconds).
Allow the other controller to reliably detect this interruption.
Use the detected event to toggle the dry contact ON and OFF states.
Relay should remain in the same toggle state until it experience the same voltage change
Please let us know your recommendations or if you have implemented a similar solution
Equipment A initiates an event, equipment B detects it, the event is then forwarded to equipment C.
Equipment B which hosts the detector will always have 24 VDC.
Equipment B must detect the event with a 3 ms duration (my assumption, not your stated specification)
Equipment B to signal equipment C with a dry contact within 10 ms (again, my assumption)
Equipment B must toggle and latch.
This set of assumption is on the edge of reliability for electromechanical detection of the glitch.
Alternative 1
You could wrap an SSR into a latch-like circuit using steering diodes as shown in this sketch. Once the glitch is detected you could then handle the toggle or latch via alternative means. For example, you would need to momentarily disable the +24 VDC to release the latch.
Consider a small PLC or programmable relay. Unfortunately, I cannot guarantee the PLC will respond fast enough. I have measured the time in larger PLCs but not the smaller PLC.
For the Alternative 1 what do you suggest for SSR part and to trigger the event from Equipment A what product do we have that can provide input to SSR at location B
A colleague, @rick_1976, suggested that I may be looking at this from the wrong angle.
Do you need a purpose-build piece of equipment or a power diagnostic analyzer? We could continue to explore a dedicated solution or look to advanced equipment such as the Fluke 3540. Full disclosure, I do not know if the Fluke will meet your needs.
It may be worth speaking directly with a Fluke application engineer.
I suspect your facility already has the Fluke or a similar meter somewhere in the tool crib.
It looks like you are local, DM if you would like to talk.
Yes, an Arduino could be used to provide proof of concept:
The 24 VDC Weidmüller 8950720000 is used to level shift the 24 VDC to the Arduino 5 VDC. Don’t forget to add a resistor (1 kΩ should be fine) between the SSR and the Arduino 5 VDC. The Arduino input pin is connected to junction of the resistor and the SSR output.
The Arduino R3 Uno is capable of performing the delays and latching.
Hazard: The voltage will need to drop down to somewhere around 10 VDC before the input SSR will toggle. If this is unacceptable, an advanced analog solution using something like a windowed op amp may be required.
