Koyo and numbers/math?????

Hello all,

I have been working on a progam for some time now. I have been here a few times and have always been lead in the correct direction, for that thank you. It is that time again..... I have some questions about Koyo (AD) and math with large numbers. I am using a D0-06DR-D PLc. What I am trying to do is calculate the % of gallons that can be treated in a pretretment softner before it has to be regenerated. I hope you got that....lol The math is rather easy, just large numbers, I cannot get the answers to come out correct. Most of these numbers are stored in a Vmem location and change depending on system perameters. Here are some of the numbers that will be used to help out. 17,700 X 2 = 35,400. 35,400 / 5 = 7080. 7080 - 273 = 6708. 6708 / 7080 = 0.96. 0.96 X 100 = 96% charge left. I keep getting 0 for an answer.

Thanks,
Micheal

What format are you using? Are you using Real Numbers?

If should look something like this

LDR V1000
MULR R2
DIVR R5
SUBR R273
DIVR R7080
MULR R100
OUTD V1002

Any type of integer format will give you an answer of zero.
You can either use floating point as CroCop suggests, or long integer if the PLC will support it. In long integer, you should multiply the neumerator by 100 before the divide to get 1% accuracy.

With Koyo integer math the input and results must be between 0 and 9999, although intermediate results may be larger.

You have two choices. You can use real numbers, or you can scale the values to stay within the limits. For example, you could use units of hundred gallons or thousand gallons.

Thanks guys, as always you advice gave me what I needed to solve my issue. I ended up scaling the numbers to fit within the processors limits. Now I have another question. I need to write some logic that assigns preference to up to five events that "might" try to happen at ther same time. I can have up to five valves trying to turn on at the same time. I am trying to set it up so only one at a time comes on and if it two need to come on at the same time the one with priorty will come on first then when it is finished the second one. As always I look forward to the advice and if you need more information ask away. THANKS!!!!!

EDIT.........After posting and going back and working on it some more, I think have it worked out. Feel free to post suggestions, yours may be better than mine. And I may not have it right....lol

Later,
Micheal

Let's say your 'events' are X0 through X4. And the associated outputs are Y0 through Y4.

Your lines then are

 

   X0                                         Y0

---| |----------------------------------------( )--

 

   X1   X0                                    Y1

---| |--|/|-----------------------------------( )--

 

   X2   X0   X1                               Y2

---| |--|/|--|/|------------------------------( )--

 

   X3   X0   X1   X2                          Y3

---| |--|/|--|/|--|/|-------------------------( )--

 

   X4   X0   X1   X2   X3                     Y4

---| |--|/|--|/|--|/|--|/|--------------------( )--

Of course an occurance of X0 while X1 is turning on Y1 will turn off Y1 and turn on Y0. Is this what your want?