Sum part of an array starting at element 70

TheWaterboy

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TheWaterboy
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I'm trying to sum the last part of an array starting at element 70 for 30 elements.

I placed a 70 in the .POS element of the FAL and it gets cleared to zero at each pass. I haven't seen examples that start anywhere other than zero yet so I gotta ask.

What is the proper way to start at somewhere other than zero?
 
I get where you are going with those but I can't enter anything but a DINT into the POS field of the FAL instruction. I tried entering a starting position withe MOV on the rung above and still resets to zero.
 
TheWaterboy said:
I get where you are going with those but I can't enter anything but a DINT into the POS field of the FAL instruction. I tried entering a starting position withe MOV on the rung above and still resets to zero.
Click to expand...

But you can write a value to the POS of the control. MOV 70 MyControl.POS
 
How big is your array
if you are starting at 70 and using 3 elements then the array length must be at least 101
I got in the practice of always making my arrays larger then I need to avoid index overrun and processor fault
 
TheWaterboy said:
Placed LoopyDoop on a trend and watched .POS. It goes from zero to 70 and back to zero. What is going on with this instruction?
Click to expand...

In my example, it is 0 when the instruction is not true, It's first iteration starts at 70 once the instruction goes true. I had a value in [0], it was not included in the sum.
 

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