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Old December 28th, 2017, 10:44 AM   #1
argetsad
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AOI Help RS LOGIX 5000 - Bit On during certain hours

I'm looking for an AOI that I can import 2 different times (let's say 1:00 AM and 4:00 PM (12 hour format)). If the current time is between these two times then it turns on a bit, if not the bit is off. So the heater is active at 1AM and not active after 4PM for that day of the week only. The next day might be active from 5pm to 7 pm. The following day different again.

I am creating a 7 day Setup for a water heater. The heater needs to be active between hours X and Y and the heater element is on when the temp is lower than the max value. I know I could use some logic to do this but I'm looking for a cleaner approach.

I'm using RSLOGIX5000, 1769-L30ER, ver 24.01, and an automation direct HMI Cmore Ver 6.31

Thanks ahead of time.
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Old December 28th, 2017, 01:45 PM   #2
Aardwizz
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Sometimes "some logic" IS the cleaner approach. If you are only going to use this AOI once to drive your one heater (but moving different times into it on different days, then you might as well just code the function. AOIs are best for reusable code.

Let's imagine this mythical AOI you're looking for:
- "1:00 AM" is a string. Are you planning on passing a string to the AOI and then parsing it out? Unlikely. That means that you'll have an Starting_HH input, Starting_MM, and Starting_PM (Bool). Same with Ending_HH, etc. The way you write you HMI interface to this will be how the PLC data will be.

- For outputs, do you just need a "BETWEEN" bit?

- For the logic, what if the Ending < Starting (i.e, Start at 11:00 PM, End at 1:00 AM)? Does the logic allow that or not?

With this, you can write your own AOI faster than it'll take to wait around for someone to hand it to. If AOI is where you want to go, which I doubt.
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Old January 5th, 2018, 12:30 PM   #3
saultgeorge
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I would write the routine for operating the water heater, and use the clock in the controller. You could then enter the start time and stop time into your routine from your HMI , and when the time equals say the start time, then use a one shot to start and then the same with stop.
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Old January 5th, 2018, 12:46 PM   #4
janner_10
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I wouldn't bother with an AOI, just read the wall clock and use LIM and EQU in a routine.
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Old January 5th, 2018, 01:05 PM   #5
jstolaruk
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Quote:
Originally Posted by janner_10 View Post
I wouldn't bother with an AOI, just read the wall clock and use LIM and EQU in a routine.
Agreed, unless you have a bunch of heaters with different ON-OFF times.
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Old January 5th, 2018, 01:57 PM   #6
RonJohn
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Quote:
Originally Posted by janner_10 View Post
I wouldn't bother with an AOI, just read the wall clock and use LIM and EQU in a routine.
To go a step further, use a day of week AOI with the value as a pointer to elements of a start time & stop time arrays for your limit values.
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