Two LEDs as indicators, only want one lit at a time

[Customcables067]

Hi-

I'm trying to design a circuit where only one of two status indicators are lit at any point in time.

Basically-an external sequencer gives power to each of 6 phases every X seconds. The unit provides 24vdc outputs as indicators for each phase to connect a bulb, LED (whatever, really). The problem is the sequencer doesn't turn off the led to phase 1 when phase 2 receives power. Same with 2 to 3, etc. This is by design!!! What I want is to make a circuit that shuts off the indicator for the first indicator (phase 1) once phase two receives power.

Thanks,

 

[harold777]

I think you need to supply a waveform (timing) diagram. Six phases?

This would clear up exactly what you desire.... if you add a waveform for the LEDs (On/Off)

This should be easy enough if there is a digital clock somewhere, although if you are trying to indicate peaks (of a multi-phase sine generator), things will be more difficult if there is no external (input) clock signal. I would expect this to be at a multiple of the OP frequency.

 

[Customcables067]

A few clarifications:

The sequencer unit is simply putting out six different 24VDC indicator signals. I want an LED to be attached to each isolated signal and light when the sequencer turns that specific LED on. But once a second LED turns on, I want the first one to turn off. If possible, I don't want the timing to be externally controlled. Just the first light turning off when the second light turns on.

 

[ccurtis]

I looks like you are talking about three pairs of indicators, really. No?

What is the sequencer putting out when it is not putting out 24 VDC? Ground, or open circuit?

 

[Customcables067]

Let me simplify this further, as the sequencer seems to be confusing. (Perhaps my lack of electronics engineering is getting in the way).

1 power supply.
6 circuits are integrated with the supply.
Each circuit includes a switch which provides power to the LED indicating that circuit has been powered from the power supply.

As each circuit is powered, the LED turns on with it (from the power). All of this is enclosed in one, manufactured enclosure. One switch starts the sequence to power on the circuits (one at a time, in a predetermined order).

Each circuit also has a remote status indicator contact. They can be used to wire duplicates of the indicators to indicate when a circuit has been turned on.

Via these remote indicators, I want to wire all 6 LEDs to a separate display. When circuit one receives power, I want circuit one's LED to illuminate. When circuit two receives power, i want circuit two's LED to illuminate and circuit one's LED to extinguish indefinitely.

 

[ccurtis]

Try the attached circuit. I am assuming that the remote indicator output is open circuit when it is not outputting 24 VDC.

 

[Customcables067]

I understand the circuit except the diode looking device in the center that is filled in dark. is this what would make the first led turn off when the second one turns on?

 

[ccurtis]

Yes. Just about any ordinary silicon diode will do. The top input is for the top LED and the bottom input is for the bottom LED. When the bottom LED is on, the top LED cannot illuminate. Use half-watt resistors.

 

[Customcables067]

Thanks so much! I'll give that a try! I'm assuming I can keep linking more of these together if I had an application for more than 2 LEDs?

Thanks again!

 

[ccurtis]

Thanks so much! I'll give that a try! I'm assuming I can keep linking more of these together if I had an application for more than 2 LEDs?

Thanks again!

You're very welcome. As long as the same pattern of output activation from your box applies (the outputs are activated in succession and stay activiated) the linking can be repeated for additional outputs (LEDs).