Using Micrologix 1200 two INT DIV to FLOAT

I need to divide two INT values N7:1 and N7:2 and I am trying to store the result in F8:0 using the DIV instruction, but I am getting a error "invalid range".

+-----+
|DIV |----
|N7:1 |
|N7:2 |
|F8:0 |
+-----+

What I am trying to accomplish is the rate Good Parts / Total Parts * 100 to get the percentage.

I am also using the F8:1 for the percentage of downtime using 2 RTOs and both Float values I will show them using a PV.

But I am stuck with the DIV.

Thanks in advance.

Edwin

I'm not positive about this but you may need to MOV one of the N7 values into a floating point register before doing the divide. It could be choking because you're trying to divide two integers (where the result would normally be rounded) but expecting a fractional result.

When I tried it I didn't get any errors. Are you using a series C or later processor? Only C or later processors support floats in the ML1200.

The ML should do the type casting to match the destination address before performing the divide. You can force the type casting for the DIV as Kolyur suggested. Multiply N7:1 by 100.0 first to force the type casting by multiplying by the float constant 100.0, enter constant with included decimal) and put the destination in F8:0. Then Div F8:0 by N7:2 and put the result back in F8:0.

MUL N7:1 100.0 F8:0
DIV F8:0 N7:2 F8:0

Typically with A/B ladder logic math instructions, the destination typecasts the operation.

There may be exceptions with the newer Micrologix platform, but your logic should generate the results you expect from a typical RSLogix500 program.

Reading the pdf...

Hmm...

thanks to all the solutions was doing the type casting.

MUL N7:1 100.0 F8:0
DIV F8:0 N7:2 F8:0


Edwin