Micrologix help? Simple timing circuit logic?

I am a newbee who could sure use some help...

I am using RSLogix 500 and a Micrologix 1400.

Can someone help me with some simple ladder logic that once a day will start a sequence that would initiate an ouput, time that output for 5 minutes, stop that output, then initiate another output, time it for 8 minutes, stop that ouput and repeat until it competed 8 cylces?
I am stuggling with it...any help would be wonderfully appreciated!

Can you show us what you have so far?

I hope this is not a student homework exercise.

Some links on Real Time Clock and manual.
Links:
http://www.plctalk.net/qanda/showthread.php?t=49060
http://www.plctalk.net/qanda/showthread.php?t=48905
http://www.google.com/url?sa=t&source=web&cd=4&ved=0CEIQFjAD&url=http%3A%2F%2Fsamplecode.rockwellautomation.com%2Fidc%2Fgroups%2Fliterature%2Fdocuments%2Frm%2F1766-rm001_-en-p.pdf&ei=yOjSTf2MFY-6tgeat-WPCg&usg=AFQjCNHiB1raVgiSkiIm49rTBRXQVPbG6Q

Here are some ideas that may or may not work.

The real time clock instruction can be used for your once a day determination. Use this to Start a "Cycle Enable " rung that has a seal-in branch.
Next rung:
Use the output from the "Cycle Enable " rung to turn on the 5 minute timer.
Next Rung:
You will need a TT (Timer Timing) bit from the 5 minute timer for the first output.
Next rung:
Use the DN bit from the 5 minute timer to start the 8 minute timer.
Next rung:
Use the TT (Timer Timing) bit from the 8 minute timer for the second output.
Next rung:
Use the DN bit from the 8 minute timer to pulse a counter. Set the Counter preset to 8. Use the Counter DN bit to stop the cycle. Put it in the "Cycle Enable" rung.

thank you so much. no, this is not a homework assignment.. not at 52.. lol man, I wish it was!
the problem I have is that I don't know how to use the real time clock to start the cycle... as a "cycle enable" as jrwb4gbm mentions.
i don't know what instruction to use to reference the clock to "enable the cycle".
the timing part afterwards, I think, I am ok with.

In RSLogix500 look for 'Functioon Files' on the left. Open it. Now look for the RTC tab. Click on it.

The parts of the date/time are accessed by the name RTC:0.xxx with 'xxx' being the name of the item. The current minute is "RTC:0.MIN". It is a number just like any in the N7 file. But don't try writing to it. Just use the controls shown while online.

A compare like EQU RTC:0.HR 7 would be true from 7:00 AM tthrough 7:59 AM. It's a 24 type clock. If you need to narrow it down add a second compare for the minute. Etc.

(I'm 60 and still consider myself a student.)

See where that takes you.

mazzjazz said:

i don't know what instruction to use to reference the clock to "enable the cycle".
the timing part afterwards, I think, I am ok with.

Click to expand...

EQU
It's used to compare values and test for equality. Think of it as a switch that turns on only when the two values being compared are identical.

You can use it on any integer or floating point values. You can even use it on ASCII characters or groups of status bits, input points, etc.

I don't know the "address" of the RTC in the new Micrologix, but you can find it in the manual and then use the EQU.

I would put two EQU statements in series, one for the hour, and one for the minute, then OTE to a bit with a symbol name (Start_Time) that will be true for that whole minute.

That bit, or relay, if you will, can be eXamIned for Closure (XIC) to start your first timer. Use the timer TT bit to drive the output, so that your timer could be less than one minute and still work.

Use the first timer DN bit to start the 2nd step, and so on and so forth.

Thank you all for your help! I will work on this tomorrow, time permitting, and let you know how it goes.

Thank you all for your input! I have a program that I think will work, based on the input from your helpful suggestions. I just need a little jump start to get me going.

mazzjazz said:

Thank you all for your input! I have a program that I think will work, based on the input from your helpful suggestions. I just need a little jump start to get me going.

Click to expand...

Post it here, the .rss file ( zip it first). And someone will take a look.