Timer - Relay
Timer - Relay
(OP)
It seems that my previous post has been deleted from the message board; so here's my repost with a few more details.
What I'm trying to do it trigger a relay (from closed to open) for a variable amount of time.
The start trigger is going to be a momentary switch (mercury switch). When depressed, I need a timer (555?) to open the relay for a specific amount of time, at which point it will revert to being closed again. The times will be from 10ms to as much as 1s.
If the switch is still depressed at the end of the timer sequence, I'd like to leave the relay open and reset the timer and start again.
The whole thing needs to run off a DC power supply between 11-15 volts (maybe a little more...) and hopefully the timer should not be affect by the voltage too significantly.
As I mentioned before, I not very much of a hardware kind of guy; I'm more the programmer type. However I think this circut might be very useful for many people.
Any help would be appreciated. I'd like to get something basic going at first and then build on it as I learn more.
Thanks very much!
Nicholas
erkware@yahoo.com
What I'm trying to do it trigger a relay (from closed to open) for a variable amount of time.
The start trigger is going to be a momentary switch (mercury switch). When depressed, I need a timer (555?) to open the relay for a specific amount of time, at which point it will revert to being closed again. The times will be from 10ms to as much as 1s.
If the switch is still depressed at the end of the timer sequence, I'd like to leave the relay open and reset the timer and start again.
The whole thing needs to run off a DC power supply between 11-15 volts (maybe a little more...) and hopefully the timer should not be affect by the voltage too significantly.
As I mentioned before, I not very much of a hardware kind of guy; I'm more the programmer type. However I think this circut might be very useful for many people.
Any help would be appreciated. I'd like to get something basic going at first and then build on it as I learn more.
Thanks very much!
Nicholas
erkware@yahoo.com





RE: Timer - Relay
To do this you need to trigger the timer with the opening of the switch contact, not the closing switch contact. You will need some additional logic to provide an OR function so that either the closed switch or the timer, while it is running, keep the relay energised. This energises the relay for an indefinite time, while the switch remains pressed, and then maintains it for your pre-set timer period after it is released. The "logic" could just be two diodes in the simplest case, or for the supply voltage you specified you could use CMOS gates and timer from the 4000 series.
RE: Timer - Relay
RE: Timer - Relay
Any recommendations on a specific product number?
Nicholas
RE: Timer - Relay
This is claimed to go down to 50ms. 10 ms is pretty short, but do a Google search on time delay relays and maybe you can turn one up.
dpc
RE: Timer - Relay
i know they have a timer with reset and start configuration..you can use use it as an off-delay, on delay, etc....there is a corresponding chart for its application which will help you select what you need..
runs at 24VDC...other voltages also available but i am not sure if they have 12V ac or dc supply..you can set the dial for sec or hr....if i'm not wrong the part number is H3CR...i use this timer in lots of applications and i am quite happy with it because of its "flexibility"..
this timer should do the job.
good luck
dydt
RE: Timer - Relay
RE: Timer - Relay
RE: Timer - Relay
Nicholas
RE: Timer - Relay
Hope this helps!
RE: Timer - Relay