Jump to content
shh

Converting two 16 bits registers to float

Recommended Posts

Hi,
What is the best solution for converting two 16 bits registers from modbus device to floating point in UniStream?  2x16 bit registers = 32 int to float. (IEEE754 single pr).  Is there any FB for this kind of conversion?

The device information: 

Quote

0x12345678 , shall be written in two consecutive registers, where the first register is 3499. Therefor the value has to be transmitted in the following way:

                               Reg 3499, high byte  0x34
                               Reg 3499, low byte 0x12
                               Reg 3500, high byte 0x78
                               Reg 3500, low byte 0x56


I don´t believe I have to do this manually with calculation  according to standard IEEE 754. If anybody know any method, it will be appreciated.

  • Like 1

Share this post


Link to post
Share on other sites

You can copy the 2 16 bits registers (assuming it is an array of 2 Int16) to a Buffer using "Tag to Buffer". (or use 2 Tag to Buffer" elements, but with an offset of 2 on the second copy).

Then use a "Buffer to Tag", and copy 4 bytes from offset 0 from the buffer into a Real number.

 

Depending on how the value is sent, you might need to swap bytes on the buffer before copying it to Real.
 

 

  • Upvote 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...