Real to Int

r2i_REAL_in (Data type: REAL):

The real number to convert.

r2i_Precision_in (Data Types: UINT8, UINT16, UINT32):

Number of decimal places to add to the fractional part.

r2i_INT_out (Data Types: INT8, INT16, INT32):

this is the integer part of r2i_REAL_in, no matter what the value of r2i_Precision_in is.

r2i_frac_out: (Data Types: INT8, INT16, INT32):

This is the fractional part of r2i_REAL_in, rounded to the specified number of decimal places, multiplied by 10^( r2i_Precision_in ).

There’s a special case when r2i_Precision_in is 0 (ie. round to the nearest integer): when the magnitude of th fractional part is less than 0.5, it will be 0, otherwise it will be 1 or -1, (the same sign as r2i_REAL_in). To get the correctly rounded number, you need to add r2i_frac_out to r2i_INT_out

The behaviour when the number is too big to fit into either of the integers seems to be inconsistent. If r2i_INT_out is an INT32, then it will 2 147 483 647 if r2i_REAL_in is bigger than that, or -2147483648 if r2i_REAL_in is smaller than that. INT16s and INT8s sometimes overflow instead. (i.e. 128 becomes -128 if r2i_INT_out is an INT8), but it doesn’t do this for all values). I’d avoid using this function in this situation if at all possible.

Examples:

Int to Real

i2r_INT_in (Data Types: INT8, INT16, INT32):

Integer part of value. Not actually necessary, because you can do everything without it.

i2r_FRAC_in (Data Types: INT8, INT16, INT32):

This is the only way to populate it the fractional part of the output, but it will also contribute to the fractional part.

i2r_DECPOS_in (Data Types: UINT8, UINT16, UINT32):

This controls how i2r_FRAC_in is intepreted. Values above 7 result in the fractional part being ignored.

i2r_REAL_out (Data type: REAL):

The Real output value. This is calculated as:
i2r_INT_in + i2r_FRAC_in / 10 ^ ( i2r_DECPOS_in )

Examples

D = A + B x 10 ^ (-C)

Real to Int

A = XXXXXX.YYYYYY

C = XXXXXX

D = Round 0.YYYYYY to B decimal places, then multiply by 10 ^ B

At least I think this is what it’s supposed to do – it seems to have some issues:

• Rounding close to 0.5 can be somewhat unpredictable. e.g. A = 5.246, B = 1 will give D=3, not D=2 as it should.
• Note that the Integer part is always simply truncated – don’t expect this function to Round correctly – e.g. A = 12.99, B = 1 will give C=12 and D=10, instead of C=13, D=0 as you might expect!