Off delay circuit board great for DIY

[ASommers]

http://www.cctvonlinestore.com/product_info.php?cPath=1007_18&products_id=453057106
Thought I'd share this with you guys.
This is what I plan on using to make an ATO. Just need a float switch 12V power supply and a pump. I have more trust in this than using a latching relay.

 

[Bergovoy]

what does it do???

Is it just a timer???

 

[ASommers]

Yeah basically with a built in relay. when it gets a trigger from say a float switch it be programmed by turning the knob on the side to turn on a pump any where from 1 to 60 sec. No need to rely on a second switch to turn off the pump so less chance of causing a flood.

 

[ASommers]

Actually I don't think it has to be reset, just it turns on once and then off then it requires to be re-trigger to turn on again.

The ELK-960 Delay Timer is designed to be an economical and flexible solution for any general-purpose timer application. The unit can be configured for use on 12 to 24V systems, with positive or negative trigger logic. Positive triggers can be as low as 4.5V. Setup is quick and easy with thumbwheel adjustment between 1 and 60 seconds. A quick jumper setting converts the time from seconds to minutes. The Timer can be configured to activate once for each trigger, or free-run as soon as power is applied. Relay can be configured to be normally on or normally off.

FEATURES:
12 to 24 Volt DC Operation
Adjustable Time Delay
SPDT (Form "C") Relay
Low Current Input Trigger (<1mA)
Selectable Positive or Negative trigger
Selectable Initial Relay State: ON / OFF
Operating Modes: One-Shot or Repeat
LED Indication of Relay State
Lifetime Limited Warranty

SPECIFICATIONS:
Operating Voltage:
Current Draw:
Time Settings:
Relay Contacts:
Size:
Trigger Voltage 12 to 24 Volts DC.
40 mA DC with relay on.
1 to 60 Seconds or 1 to 60 Minutes.
Form "C", 7A @ 30VDC, 10 A @ 125VAC.
3" x 2.2" x 1" (Fits Standard. Snap Track).
4.5 - 24VDC.

 

[ASommers]

You can goto there site. At the bottom there are some examples of how to use.
http://www.elkproducts.com/products/elk-960.htm

 

[Bergovoy]

I know a timer on the ato is a good idea as a back up, but the issue may still be that the timer youpropose to use is after the float switch and therefore negating the redundancy of a back up timer.

I have the timer at teh power supply of the float switch, so that there is only a chance that the float could malfunction for a short period of time.

It is kinda of the same thing but still different.
If your float were to malfunction ON,then the timer in your case would prevent thewater from flowing for too long.

But if you were to have a malfunction with your timer / float switch unit, you maybe either on for too long or never on... Seems like the timer should be totally seperate...

Not sure thta makes sense, but for now,I am going with it...

Also, how many redundant systems do we need. On for the main back up, one for the back up oftthe back and so on and so on...

Somewhere there is a weak link in a chain, and that usually is operator err...

 

[ASommers]

Have less issues with it running a little low so if it never came on I would here the extra noise in the sump or see the micro bubbles from the pump pulling in air from the surface. It's just an idea compared to a $70 ATO and maybe a little better than the ones with just a relay and 2 floats. I try to save where ever possible. Which I know isn't always the best thing in this hobby.