Can ATX PS supply RESET function?

[CharlesEF]

Hi All,

I am using a ATX computer case as a SCSI drive case, no motherboard
installed. Can I connect the RESET button directly to the ATX power
supply? I would like to be able to hit the RESET button and have all
the drives recycle, instead of turning off the case as I currently do.


Thanks for any help,

Charles

 

[kony]

Hi All,

I am using a ATX computer case as a SCSI drive case, no motherboard
installed. Can I connect the RESET button directly to the ATX power
supply?

yes but it won't do what you want, it's turn on the supply
for only a moment while you held down the button then it'd
turn off again the moment you let off the button.

I would like to be able to hit the RESET button and have all
the drives recycle, instead of turning off the case as I currently do.

"Recycle"?
What do you hope to gain by doing this? If they need reset,
there's a problem and they should be replaced immediately,
right after copying off the data.

To reset the drives via power cycling, you have to actually
cut the power, which with ATX supply means opening the PS-ON
to Gnd connection. So long as your on/off switch currently
used, is closed, the supply stays on and no reset will reset
them... if you had a need to reset them which I dispute.

 

[CharlesEF]

yes but it won't do what you want, it's turn on the supply
for only a moment while you held down the button then it'd
turn off again the moment you let off the button.



"Recycle"?
What do you hope to gain by doing this? If they need reset,
there's a problem and they should be replaced immediately,
right after copying off the data.

To reset the drives via power cycling, you have to actually
cut the power, which with ATX supply means opening the PS-ON
to Gnd connection. So long as your on/off switch currently
used, is closed, the supply stays on and no reset will reset
them... if you had a need to reset them which I dispute.

Hi,

OK, now that I think about it you are right. I have an AT power switch
(1 side) connected to pins 14 and 15. This is how I turn On/Off the
case.

When I have to reset my main computer (does happen sometimes) I have a
long wait to boot becase a lot of the external SCSI drives are in
'Sleep' mode. I was hoping I could use the reset button on the
external case to 'Wake' the drives up.


Thanks for your help,

Charles

 

[kony]

OK, now that I think about it you are right. I have an AT power switch
(1 side) connected to pins 14 and 15. This is how I turn On/Off the
case.

When I have to reset my main computer (does happen sometimes) I have a
long wait to boot becase a lot of the external SCSI drives are in
'Sleep' mode. I was hoping I could use the reset button on the
external case to 'Wake' the drives up.

The easiest way to do that would probably be to take a dual
pole, dual throw relay, hook the PSU output (power harness
to drive plugs) +5 & +12V up to the normally closed
contacts on the relay and use the reset switch to energize
the relay momentarily, thus opening the drive power circuit
and power cycling them. Since the PSU stays turned on,
you'd simply take whichever of the power rails is most
accomodating to the rating of the relay (and/or through a
resistor to limit current) to energize it.

 

[CharlesEF]

The easiest way to do that would probably be to take a dual
pole, dual throw relay, hook the PSU output (power harness
to drive plugs) +5 & +12V up to the normally closed
contacts on the relay and use the reset switch to energize
the relay momentarily, thus opening the drive power circuit
and power cycling them. Since the PSU stays turned on,
you'd simply take whichever of the power rails is most
accomodating to the rating of the relay (and/or through a
resistor to limit current) to energize it.

Hi,

Yes, thats an idea I could do.


Thanks for the help,

Charles

 

[kony]

Hi,

Yes, thats an idea I could do.

Keep in mind the current, several drives will draw a few
amps (roughly 0.5A per rail per drive) so the relay needs
rated accordingly. There'd be even more amperage at initial
spinup, though if your controller supports staggered spinup
that will reduce the current, though that feature could also
be part of the reason why it takes so long for your drives
to be recognized when you cycled the system.

 

[CharlesEF]

Keep in mind the current, several drives will draw a few
amps (roughly 0.5A per rail per drive) so the relay needs
rated accordingly. There'd be even more amperage at initial
spinup, though if your controller supports staggered spinup
that will reduce the current, though that feature could also
be part of the reason why it takes so long for your drives
to be recognized when you cycled the system.

Hi,

Yes, I see what you mean. Maybe it would be better if I just waited
for the drives to 'Wake' up. During a reboot I have to wait for the
SCSI controller to detect each drive. Since a lot of the drives are in
'Sleep' mode this takes some time (I multi-boot several OS's and have
18 external SCSI drives).


Thanks for your help,

Charles

 

[kony]

Hi,

Yes, I see what you mean. Maybe it would be better if I just waited
for the drives to 'Wake' up. During a reboot I have to wait for the
SCSI controller to detect each drive. Since a lot of the drives are in
'Sleep' mode this takes some time (I multi-boot several OS's and have
18 external SCSI drives).

That's a lot of drives, you'll certainly need a heavy-duty
relay if that's the route you want to take.

You're going to have to wait for the controller to detect
them either way, so it would seem a good idea to test
whether cycling the drives has any benefit before trying any
reset strategy. That is easily enough done, just flip the
power switch on the PSU off and on a second or two before
you'd regularly anticipate pressing the reset switch as you
aimed to do.

Do you need high throughput? If not, you might consider
having these all in a static fileserver, networked Gigabit
rather than a desktop fuller-featured system that is more
prone to needing rebooted.

 

[CharlesEF]

That's a lot of drives, you'll certainly need a heavy-duty
relay if that's the route you want to take.

You're going to have to wait for the controller to detect
them either way, so it would seem a good idea to test
whether cycling the drives has any benefit before trying any
reset strategy. That is easily enough done, just flip the
power switch on the PSU off and on a second or two before
you'd regularly anticipate pressing the reset switch as you
aimed to do.

Do you need high throughput? If not, you might consider
having these all in a static fileserver, networked Gigabit
rather than a desktop fuller-featured system that is more
prone to needing rebooted.

Hi,

Yes, that is a lot of drives. I should have said that I have 2
external cases, with 9 drives each, not 1 big one. Depending on which
OS I boot with depends on how many drives are being used. Like when I
boot in to my developement system only 2 drives are used leaving the
rest to go in to 'Sleep' mode (and this mode is where I need to hit the
reset button very often. You know, testing programs that do not work
like I wanted). If the drives are not sleeping then the detection goes
very quickly. But it takes time to wake a drive. I know that turning
the case off then on again will put the drives in ready state.

I quess I better just leave well enough alone and forget my idea about
using the reset button. At least with a manual power off I can wait
for the drives to stop spinning before I apply power again.


Many thanks for your insight,

Charles