adjustable timer

[duckman]

A customer wants me to overhaul a machine , sand blast and paint , new bearing housings , and electric controls , now the bad part they want to be able to start and run machine for up to 72 hours , after time set times out drop out motor starter , not a repeat cycle it may only run 1 cycle a week . I've looked and can't find a count down timer digital or mechanical . HELP

[MaxHeadRoom]

What you need is a Smart Relay, they have an option with a real time clock.
You also get the bonus of easily programming the various I/O. Mini PLC in effect.
I would say it was an ideal application?
They are practically identical units made by Siemens, Idec, GE, Telemecanique, Omron and others.
Max.

[browne92]

Maybe something like this:

http://www.ebay.com/itm/12-Function-...item337c68306a

[Keith_W]

Hi duckman,
Have a look at Grasslin Timers as they have 24Hr 7 Day Timers. If your customer is looking for a easy to set variable timer then as Maxheadroom has suggested a Smart Relay is a good choice with the real time clock and you can wire in some pushbuttons and thumb-wheel controls for the time settings, they usually have a display so you can see what settings you have made and the software to program them is easy and free.

Regards,
Keith_W

[Jon Heron]

A simple Omron timer is what you want, in my opinion.
This one should do the trick just fine.
http://www.ia.omron.com/product/fami...index_spc.html
Cheers,
Jon

[MaxHeadRoom]

A simple Omron timer is what you want, in my opinion.
This one should do the trick just fine.
http://www.ia.omron.com/product/fami...index_spc.html
Cheers,
Jon

The one problem is they have to be manually activated and then they do not run on a real time clock, whereas the smart relay you could program it and leave it, also use to control other manual machine functions if necessary.
Max.

[Jon Heron]

Hi Max,
They can be activated remotely with an input as well as a switch, push button, etc. they also have internal adjustable start delays, etc. these timers are used primarily in automated setups with the timer inside a control panel where after being set up initially, it will never need to be touched again. These are the industry standard for timing applications in my experience.
I am not sure what you mean by

they do not run on a real time clock

they operate on an internal clock cct just like any such device, including a smart relay.
It is only a timer though and certainly is not suitable to control any other functions other than timing.
Cheers,
Jon

[MaxHeadRoom]

The OP mentioned running the cycle once a week, with the smart relay it could be triggered at a particular time of day, or day of the week, AFAIK the Omron timer does not do this.
The programmable inputs/outputs can override this if needed without affecting the time cycle.
Max.

[CCWKen]

The OP said it may run once a week. It sounds to me that it's not a fixed schedule and the start-run could be any time of the day on any day of the week so programming a particular time or cycle is not adequate. It sounds like they want to set how long the machine will run then stop after that amount of time. They may want to start it on any day of the week and run for up to 72 hours. A simple timer control should work. (With appropriate motor starter relay/cutout.)

Added: I use an older Omron timer on one of my spot welders. It has different time ranges that apply to the dial setting. This makes it possible to set any time from about 5/100 of a second to 100 hours. Some of the newer models have wider ranges and come in digital form.