Conversion from negative single to unsigned 16bit integer

[GerdW]

Hi Saisravan,

So I need to give -ve values to drive...IE ABB ACS880 drive. My modbus function is unsigned 16 bit.

Read the manual of your ABB inverter!

It surely contains information on how to scale your float "ve" value to the U16 value you send over MODBUS…

[SravanKumarAtla]

Like this I'm converting SGL to I16....but I'm not getting exact values ...if give -10 means drive is setting -2000 rpm speed ...

[SravanKumarAtla]

Is this right way to convert this...??

[GerdW]

Hi Saisravan,

I'm converting SGL to I16....but I'm not getting exact values ...if give -10 means drive is setting -2000 rpm speed ...

And what does the manual state about the conversion to U16 for this speed parameter?

When "set speed" is -10 then you get an I16 value of -31978. Is this the correct value expected by your inverter?

(I would expect an offset of 32768 instead of 31968: read the inverter manual (again)!)

[SravanKumarAtla]

Now Im getting correct values...Thanks for responding...!!

[GerdW]

Hi Saisravan,

do you mind to show your solution so others may learn from it?