Delay for digital signal? (not audio related)

Svart

Well-known member
Joined
Jun 4, 2004
Messages
5,134
Reaction score
7
Location
Atlanta GA USA
Ok so I am working on a variant of my Hbridge control circuitry and have run into a hiccup.. a big hiccup.. on the fault of the programmers for the micro that drives the whole clusterfuck.

I needed 3 outputs, UP, DOWN, and one for a RELAY. the up/down signals are active high as long as the command is issued. there is no pulsing, just high or low. the up/down signals were to be delayed long enough for the relay's contacts to have seated properly before current is applied through the Hbridge to minimize arcing and generally bad behavior.

now for the hiccup. the coder gave me the two UP/DOWN outputs but no output for the relay. I could easily sum this through a common cathode diode and switch the mosfet on the relay when either of the signals are actuated but we are driving a bridge of MOSFETS and SCRs that will be fully ON before the relay has even bounced once giving me a healthy arc and the potential for severe damage.

if you have read this far and haven't continued your trolling elsewhere then this is either delightfully interesting or sadistically pleasing so lets continue.

Is there a discrete(not code) way to delay the signal, keep the signal applied as long as the command is being supplied and be reset every time you stop and then give a command? of course there is but i need something with the least amount of parts and it needs to be reliable and predictable. delay of .5 seconds is typical, bonus points for adjustability.

and i wish that i could get the coder to redo this but has apparently retired and has refused to work on it again. my other choice for code work has also turned it down with a policy to only start from $cratch, refusing to work on anyone else's work.



Hopefully someone will stoke some ideas.. :?
 

moamps

Well-known member
Joined
Sep 24, 2005
Messages
1,737
Reaction score
78
Location
Croatia, HR
One idea:

updnrelay.jpg

[/img]
 

Latest posts

Top