[Beefy]

This question is primarily aimed at AMB, but is open to all comers...... I'm trying to do something a little different with an Epsilon 24, and am having some problems.

What I am trying to do is use an external relay to reverse the polarity of the voltage supplied to my Bulgin dual-colour switch; the plan is for the switch to change colour on SPDIF lock. The external relay is a spare Twisted Pear OTTO I had lying around.

On its own the external relay functions perfectly, and under normal conditions the E24 is working without issue. But as soon as the LED polarity is switched through the relay, the E24 powers down. I am guessing what happens is that as the relay starts closing/opening the LED goes open circuit, which de-stabilises the E24 and turns it off.

I can partially stabilise the E24 by running a 2.2kohm resistor in parallel to the LED, so that it never goes open circuit - this works for about 50% of switching events from the external relay, gives proof of concept, and suggests that everything is wired up incorrectly. But before I start randomly trying other stuff or different resistor values, some expert advice on keeping the E24 on and stable while the LED switches would be greatly appreciated.

Further info......
I am using this SSR which works great normally.
I am not using thermistors, and J2C is jumpered.
K1, Q1 and D2 are installed (I was originally going to use the E24's own relay for switching but decided against it), but R4 is not, thus keeping them out of the circuit.
I tried running 220ohm across the SSR's control terminal with no success.

Thanks for looking...... I look forward to your suggestions!

 

[digger945]

Could you have the line from the e24 to the led on the Bulgin going thru the OTTO in the normally closed position, then have the spdif trigger the OTTO to switch the color by reversing the polarity?

Can the e24 be used with a switch that has no led, ie. the led is not necessary to proper function of the e24?

 

[linuxworks]

if the goal is to 'manage' the color on the switch, why not use an h-bridge and that nicely 'reverses voltage' via 2 easy logic inputs.

then simply supply a 1 to the right input to get the right color.

or, is that too simple?

 

[amb]

Beefy, can you post a wiring diagram of what you're doing?

 

[Emooze]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif if the goal is to 'manage' the color on the switch, why not use an h-bridge and that nicely 'reverses voltage' via 2 easy logic inputs. then simply supply a 1 to the right input to get the right color. or, is that too simple?

Do you have a H-bridge IC in mind? Most of the ones I've come across are 4 input and you don't want to wire them to 2 without having some delay.

 

[Beefy]

Quote:

Originally Posted by digger945 /img/forum/go_quote.gif Could you have the line from the e24 to the led on the Bulgin going thru the OTTO in the normally closed position, then have the spdif trigger the OTTO to switch the color by reversing the polarity?

That is exactly what I am doing.

Quote:

Can the e24 be used with a switch that has no led, ie. the led is not necessary to proper function of the e24?

Yep. The whole thing works perfectly when the LED is not connected, including the E24 and the relay switching when it gets the right signal.

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif if the goal is to 'manage' the color on the switch, why not use an h-bridge and that nicely 'reverses voltage' via 2 easy logic inputs. then simply supply a 1 to the right input to get the right color. or, is that too simple?

It is actually more complicated to do it that way. The current method uses uses a single logic input from the SPDIF lock LED of the TPA SPDIF MUX to trigger the relay on the OTTO. The OTTO stacks with the MUX.

Quote:

Originally Posted by amb /img/forum/go_quote.gif Beefy, can you post a wiring diagram of what you're doing?

Its really exceedingly simple......

J2A to power the switch LED runs into two of the common inputs on the relay.
At the normally closed position, the switch LED is wired +/+, -/-.
At the normally open position, the switch LED is wired in reverse.
The relay is triggered by the lock LED on the MUX (the relay and MUX are powered by the same supply, the E24 is completely separate).

The relay switching works perfectly on its own.
The E24 switches perfectly on its own when the switch LED isn't wired through the relay.
When the switch LED runs through the relay, the E24 switches off immediately upon the relay flipping - but ONLY on relay flipping, it still works the rest of the time.
When I put 2.2kohms across J2A, the E24 stays on during the relay switching, and the LED changes colour correctly - but only about ~70% of the time. The other 30% of times the E24 switches off again.

 

[digger945]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif That is exactly what I am doing.

That's what I thought initially.

Quote:

When the switch LED runs through the relay, the E24 switches off immediately upon the relay flipping - but ONLY on relay flipping, it still works the rest of the time. When I put 2.2kohms across J2A, the E24 stays on during the relay switching, and the LED changes colour correctly - but only about ~70% of the time. The other 30% of times the E24 switches off again.

I have seen posts by amb addressing the cause and symptom.
Memory fails me.

 

[Beefy]

The usual problem I have seen is with SSR's not switching properly, solved by putting 220R across the relay control terminals. I tried this, and it didn't do squat

The frustrating thing is everything does work perfectly, right up until the relay triggers. And with 2.2kohm across J2A, it works exactly as intended about 70% of the time.

While I wait for more options from AMB, I might try and install R4. It being absent is the only oddity of my otherwise standard build.

 

[amb]

It would seem that the otto's relay is causing enough contact "bounce" to upset the ε24. You could try adding a small capacitor instead of your 2.2K resistor across ε24's J2A (0.1uF or maybe even smaller) and see if it helps. Otherwise, you don't have to run the LED power from ε24 at all. Why not tap it from elsewhere (with an appropriate series resistor)?

 

[Beefy]

Quote:

Originally Posted by amb /img/forum/go_quote.gif It would seem that the otto's relay is causing enough contact "bounce" to upset the ε24. You could try adding a small capacitor instead of your 2.2K resistor across ε24's J2A (0.1uF or maybe even smaller) and see if it helps.

I'll check my spare parts bag, see what I've got and report back......

Thanks!

Quote:

Otherwise, you don't have to run the LED power from ε24 at all. Why not tap it from elsewhere (with an appropriate series resistor)?

Definitely an option. I was just trying to keep all of the 'dirty' jobs separate from the other power supplies.

 

[Beefy]

Alright, so 0.1µF across J2A helps, but not as much as the 2.2kohm resistor did

How high can I go before I start hitting other issues? I have some Wima 1µF intended for y2 output coupling that could go in temporarily......

 

[amb]

Sure, try 1uF. There is no real downside. When you get into the hundreds of uF range you may notice the LED fade-in upon power up rather than turn on immediately.

 

[Beefy]

It looks like 1µF might have done the trick

Probably 99 out of 100 switches do not power down; the only way I got it to go power down was by switching it as fast as I could. And the effect of the switch changing colour with SPDIF lock is even better than I had hoped for.

Thanks so much Ti and everyone else!