Relay Timer for 2 events 1

[robert5798]

What I am looking for is a schematic for a timer that controls a relay operating at 120V 10A
I should be able to set the period of time for the contacts of the relay to be closed - then they open automatically. Then there should be a delay before the cycle is repeated.
I would like two LED indicators on it, one to indicate device is operating, the other to indicate contacts are closed. Also a start cycle button so I can begin the cycle at any time I choose.
It could use dip switches to set the hours when the contacts are closed and the delay after contacts are open. The dips must be able to set a maximum value of 36 hours or more. So the dips could use binary to represent the actual number of hours for each setting - since there will be two switches - one for each setting.
If anyuone can point me to where I can obtain such a schematic please let me know. This is notfor commercial use but for home project i am working on. My greenhouse, I want to change the hours in a day for my Venus Flytrap plants to observe and record their reaction. Personal experiments I am doing...
thank you very kindly one and all..
Bob

 

[itsmoked]

You can do it using a mind-twister of different components and then discover the need for one more feature that blows the plan.

I would suggest you find a very small inexpensive PLC then you can add features at will.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[LionelHutz]

I agree with Keith.

You could use a small programmable relay such as a Zen, Zelio, Easy or Logo to do what you want without spending much more than a fixed timer. Then, you have the added advantage of being able to change the functionality in the future.

I believe the Omron H3CR-F relay would do what you want. There is also the Omron H5L or H5S 24/7 timers.

Personally, if it is to switch 120V I'd just go to the local hardware store and get something like a NOMA weekly timer. I've got an outdoor one that's a 7-day with multiple on and off settings.

 

[waross]

I originally thought of the time clock or weekly timer as suggested by LionelHutz. I was trying to reconcile this with your comment about 36 hours. Typical time clocks are based on a repeating 24 hr. cycle.
I also thought about various timers but again the 36 hour constraint is outside the range of the cheap relays that I am familiar with.
When I read itsmoked's post this morning I was delighted. It's probably the most flexible and most cost effective solution.
Right on Keith
Not to discard LionelHutz's suggestion; If you can find a weekly time clock with seven day timing instead of 24 hr. repeating timing it will probably do.
respectfully

 

[LionelHutz]

I was thinking some more and decided I was a little confused about exactly what you wanted.

Are you looking for a timer where when you hit a button it comes on for the time setting and then shuts back off but then requires you to hit the button again to do another cycle? A Omron H3CR-A set to mode C will do this function. You apply 120V to it and also get a spot to wire the start button.

Or, are you looking for a timer that continually repeats the on-off-on-off cycle once you start it? If so, then the Omron H3CR-F is likely what you want. There really is no place for a button since you would just power it up to begin the timing. In this case, a start button would also require a control relay and possibly a stop buttin. If this operation is what you want then there's no reason you couldn't also use a 7-day timer instead and just program the days and times for the on and off operations.

waross, there are lots of weekly or 7-day or 24/7 timers out there that allow for setting on or off operations at any time during the week. There are also lots of cheap timers available at the hardware store with this functionality these days. You are quite correct that 36 hours is outside of the normal range for cheap timer relays and usually requires the more expensive relays.

 

[waross]

Hello LionelHutz
I stand corrected.
The Omron H3CR-F-300 will time up to 300 hours,
and at Lowes Hardware There's a weekly timer for $14.98
It supports up to 20 on-off events a week and random programing and it repeats weekly.

http://www.lowes.com/lowes/lkn?action=productDetail&productId=80520-207-TE05WHBL&lpage=none

or
American Tack & Hardware
Weekly Digital Timer
Item #: 80520 Model: TE05WHBL
$14.98
respectfully

 

[itsmoked]

On the PLC band wagon... Something like one of these perhaps?

http://web2.automationdirect.com/adc/Shopping/Catalog/PLC_Hardware/DirectLogic_05/PLC_Units

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[robert5798]

I want to thank everyone for their help on this. I have checked into the PLC and this is exactly what I need. This would permit me to adjust the hours per work cycle as needed, have an on of 9 and off for 6, if desired, or expanding to 36 on and 2 off.
I am not sure if there is additional equipment needed to program one of these devices, or do i just hook it to my computer's RS232 and is the software included with them to run on my computer? I am not sure on these, since i never purchased one before.
Anyone with any knowledge on this, please let me know. and thanks again

 

[itsmoked]

robert5798; The PLC is going to take a little lernin.. But once you take that time you will have a skill you can use for all sorts of modifications and similar tasks.

I have only used the top of the top versions the $60k AB ones and that was a while ago.

I'm not the one to suggest which low end one you should use.

You want one that is:
logical (most are these days)
One that has a free programming software tool.
One that has enough 120Vac inputs
One that has enough 120Vac outputs to meet your now and un-guessed at future ones.
One that doesn't cost a fortune.
One that uses hopefully USB to connect to a PC.

Guys what else am I missing?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Hello robert5798
itsmoked has pretty well covered it. Re the free software programming tool; hopefully you can get a free demo version online. If so, post the link and you may be able to get some help with the programing.
yours

 

[LionelHutz]

The Automation Direct PLC's require you to purchase the programming software as a seperate package or download the restricted version and buy a cable. Programming cable is $30 and manuals are another $30. I'd recommend you purchase the manuals because they are 2 books of probably 1000 pages total. Those PLC's are OK. We've got 5 DL05's and a DL205 running here in a communicating network and they're working OK.

I still recommend a Smart Relay (this is a mini PLC). They come with a keypad and display on the front of the unit so you can just program them directly which makes them very easy to use. Manuals are available from the manufacturers website for free to read how to program. These are the previously mentioned relays such as the Omron Zen, Telemecanique Zelio, Moeller Easy or Siemens Logo. A small one should be cheaper than the Automation Direct PLC and then it won't require any able or computer to program making field changes very easy.

 

[NWBeaver]

Being a PLC programmer myself, I think the PLC route would be fun to do, but...
It seems to me this 'experiment' could be easily done using a readily available programmable timer, such as the kind I have running the sprinklers in my yard.
It has multiple outputs and two programs for each output, so I could easily wire it up to control a relay in pretty much any way I wanted. It also allows me to manually control each output, besides having an LCD display.
I don't know what your budget is for this experiment, but even a small PLC is going to cost more than a simple irrigation timer. PLCs are nice, but you can't just go to Home Depot and get one.

 

[itsmoked]

NWBeaver I was unaware of gardening relays you could set to 36Hrs and that have LEDs that signify what the OP wants.


Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[NWBeaver]

I don't know if any irrigation timers go to 36 hours, either, I've never tried to set mine for that long of time.
But given the multiple outputs and prorgams for each output, I know that I could make it work. Perhaps sealing in a relay and then dropping it out later, if I needed more time. The display tells me when it is on and which valve output is active, but I could certainly wire up some LEDs too.
It's just an idea...
I've only been doing control systems for about 15 years, besides having a degree in electronics and being a Control Systems P.E., so I don't find any of this difficult.
If you don't understand, or don't like it, don't try it.

 

[waross]

Hey fellas look at this;
random programing for $15.

http://www.lowes.com/lowes/lkn?action=productDetail&productId=80520-207-TE05WHBL&lpage=none

I understand that it repeats weekly.
respectfully

 

[ADMIRALKEN]

I would use the PICO controller for this:

http://www.ab.com/plclogic/pico/pico.html

You can download the program for free, but the cable cost money. So...use the software to write your program, you can even test it with the software. Then once you have everything debugged, just use the built in programming interface to enter your logic. The buttons on the front will allow timer value changes etc...
Plus, the outputs are isolated, and have a pretty high amp rating.

 

[itsmoked]

Looks nice ADMIRALKEN.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[OldPfart]

If you buy an Omron ZEN or Schneider Zelio with screen and push buttons, you do not need software at all. The pushbuttons can program the unit very easily.

If you want software for one of these simple devices then fine but I have the software for both of these and would not bother - it is generally easier to use the pushbuttons and LCD display screen quite frankly.

Lets face it, the program is not going to be complicated in one of these - not like a normal PLC.