Two 16bit integers that represent one 32bit float

[bernie_carlton]

The word swapping in post #10 should have worked.

I use the calculator here to help me envision the conversions.

 

[Ash Tillotson]

Try swapping with length 2. I don't think the MicroLogix even does unsigned.

EUREKA!
That works perfect!
I had thought that "Length" would have been (1) 32bit float,
but i guess not.
I really appreciate your help!

 

[keshik]

Success!

It doesn't help that the MicroLogix documentation for the CPW doesn't actually say what value should be in the length field... have to infer it from other parts of the manual or guess and test.

 

[danw]

I'm confused.

Are the original two 16 bit 'integers' in the appropriate floating point (FP) bit format (sign, mantissa, exponent) to form a 32 bit IEEE floating point value, once moved to a word in FP format?

Or are the original two 16 bit 'integers' a 'long integer' with an assumed decimal point?

I'm assuming it is the first, because no decimal point was considered in the conversion.

 

[keshik]

I'm confused.

Are the original two 16 bit 'integers' in the appropriate floating point (FP) bit format (sign, mantissa, exponent) to form a 32 bit IEEE floating point value, once moved to a word in FP format?

Or are the original two 16 bit 'integers' a 'long integer' with an assumed decimal point?

I'm assuming it is the first, because no decimal point was considered in the conversion.

The original value was already in the proper bit pattern for a floating point number. This is why there was bit conversion done - just changing the way that the PLC is interpreting those same bits.

The original value was in two 16 bit words, but not of an integer datatype.

 

[bernie_carlton]

The RSLogix500 help file is more explicit concerning CPW's length in that it is number of words.

Too bad this varies between platforms. I tend to forget also.

 

[Geospark]

Just to put the official rubber stamp on the CPW for the MicroLogix...

43310 - Floating point in two integers to Float
Access Level: TechConnect

Regards,
George

 

[keshik]

Just to put the official rubber stamp on the CPW for the MicroLogix...

43310 - Floating point in two integers to Float
Access Level: TechConnect

Regards,
George

Showoff

Thanks for the addition.