[joeavaerage]

Hi,

As for hooking it up "dumb" with the 24V PSU just turning on when the servo drive turns on, there's a bit of a delay. As much as 2 secs where the brake is disengaged before the servo is powered up and holding station. On turning off, it's much shorter, something like 0.5 sec. When I try to turn the axle as fast as I can with my fingers, I can get about 1-1.5 turns during the turn on phase and about half a revolution when turning off.

Cant imagine what's going on. My brake locks on within a few milliseconds, I've never had the servo rotate at all between when the servo Enable signal goes inactive and the brake locking on.
There is a very distinct 'click' when the brake either engages or disengages, and that is an auditory confirmation that everything is working.

The relays you have linked to have a catch diode on the coil of the relay. The catch diode is the 'catch' the voltage spike that occurs when the current is removed from the coil. You do not want a several hundred
volt inductive spike going back into your controller. A regular diode will work, but they are a bit slow. Better off using a highspeed diode, or for little relays such as this a 1N4148 signal diode is any amount good enough.
I buy surface mount 1N4148's for less than 2 cents each in 1000 off lots.

What the relays do not have is any protection on the contact side. The electromagnetic brake is pronouncedly inductive. When the relay contacts open where is that current going to go? It will spike voltage
sufficient to cause an arc between the contacts.That is where you need a catch diode, so that is in addition to the one on the relay coil. In this circumstance an 1N4148 in insufficient, it is certainly fast enough but
not the current handling. This is where you need a high speed diode.

Craig

[GeckoSub]

Hi,



Cant imagine what's going on. My brake locks on within a few milliseconds, I've never had the servo rotate at all between when the servo Enable signal goes inactive and the brake locking on.

Craig

I will have to read the rest a few times to make heads or tails of it. But the reason I have a delay is that I am running the 24V totally dumb. There's no relay, no connection to an "enable" or anything like that. It's just hooked up directly to mains like the servo drive. The delay comes from the ~ 2 secs it takes for the servo drive to power on and hold the servo whilst the 24V PSU turns on way faster after they both get fed mains power.

As for the rest of the posts on this, I gather you think that's an unhealthy idea?

[joeavaerage]

Hi,

But the reason I have a delay is that I am running the 24V totally dumb. There's no relay, no connection to an "enable" or anything like that.

Well that explains it. there is s delay between when the mains supply is applied to the power supply module and when its output is useful. In that period of time the
brake status and the servo status are not in sync.

You need a relay or switch so the the brake is released at the same time as the servo is enabled, and going the other way the brake is de-energised, ie locked on when the servo is disabled.
Use a relay or a switch. The millisecond delays have not proven problematic for me, but I can well imagine half second and longer delays that you are experiencing would screw my machine as well.

If you do use a relay, and want it to last, then fit a catch diode. The relay will work OK without it but the contacts will suffer arc damage and likely at some point in
the future weld themselves together.

Craig