Timing circuit help 1

[mcknight]

How do I make this work, and what type of timer do I need?

A part is moving down a conveyor and hits a normally open limit switch and conveys past the limit switch and travels for about 10 seconds then I want an 110v solenoid to be energized (after the 10 seconds previously stated)and then remain energized for 30 seconds and then denergize.
If another part hits the limit switch before the 30 seconds are up then it will stay energized until there is no more parts.

 

[nbucska]

I suggest using a microcomputer: you can get very cheap
micros ( e.g. from ATMEL for << 5 usd ) but you need to program them in assembly or "C". You can get PC compatible
from <

http://www.jkmicro.com>

for <<75 usd or from <

http://www.bagotronics.com>

for about twice of this -- both
PC compatible, programmable in any PC language.

You could add a solid state switch and program it in a few
hours.



<nbucska@pcperipherals DOT com> subj: eng-tips

 

[buzzp]

On the surface it looks like a delay on make and a delay on break timer will work. The only real issue would be clearing the 30 seconds if another part comes. This could likely be handled using the same timers. Some timers have separate initiate contacts from control power. I am sure you could do it without the microcontroller but if your used to micros then a micro is the only choice (to me). Otherwise, call a timer company and tell them what you want and they will give you a solution. If you need to know timer companies then try a search. I will try to list some next time I visit.

 

[Mstrvb19]

What is the purpose of the intial 10 second time period? Is this time intergral to the time delay (i.e you really have a time delay of 40s?) or is there some other reason for it such that it must remain separate? If it is integral then you can perform the entire operation using a single time delay relay. What type depends upon the load. Use the limit switch to energize the coil of a time delay relay, such as an Agastat E7000 series. You want to use a time delay on drop out type (TDDO). The contacts of this relay will transition state when it is energized (thus energizing the solenoid)and transition again after the time delay following removal of current from the coil. As long as the limit switch opens and does not re-energize the coil (resetting the time delay) the solenoid will be de-energized after the 30 second time delay. So if I understood your question correctly,the whole thing can be done with one time delay relay between the limit switch and the solenoid.

 

[Barry1961]

One way to do this would be with..
1) Time Delay ON, 1-NO, 10 sec(T10)
2) Time Delay ON, 1-NC, 30 sec(T30)
3) COntrol Relay, 1-NO(R1)
4) Limit Switch, 1-NO, 1-NC(LS)

I will try to "draw" schematic in text, hope it makes sense.

---(LS NO)---------(T30 NC)--------(R1)
I I
I I
---(R1 NO)---I I---(T10)

----(T10 NO)-----------------------(SOL)
I
I
I--(LS NC)---(T30)

When the LS makes the first time it will latch in R1 and T10 and these will stay in until T30 times out.
After 10 sec SOL will turn on and stay on until T30 times out.
If LS does NOT make in 30 sec T30 will time out and turn off T10 and R1, reseting the circuit.

There is probably a cleaner way to do it but this is a start.

Barry1961

 

[Barry1961]

I see my schematic got scrambled.

On the first rung.
LS NO and R1 NO are in parallel then T30 NC is in series then R1 and T10 coils are in parallel.


Barry1961

 

[sreid]

One could use a PLC (Programmable Logic Controller). Mitsubishi makes the Alpha Series PLCs that are inexpensive and easy to program/use.

 

[MVRockwell]

Instead of a PLC you could you a hybrid PLC/Timer unit. Checkout the Rockwell Pico unit, it "performs simple logic, timing, counting, and real-time clock operations"

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

http://www.ab.com/manuals/cp/1760-um001b-en-p.pdf

Approx. cost $150.00 (USD)

 

[tulum]

For a similiar price you could use schneider electrics twido...

http://www.schneider-electric.ca/

http://www/en/products/automation/html/plcio.htm

Scroll down to twido.

Regards,
TULUM