Emotron floating point format & Modbus

Recommended Posts


I have been running Emotron VFD trough modbus with DAQFactory. All the basic reading and writing is working  just fine. Now I´m having a problem converting Emotron floating point format to correct decimal values.

I can read the value from 0 to 32767 with the U16 format but after that I don´t know how to continue reading the value.  I need to read this value from 0 to 200000.

Can I make this work trough "channels"  ?



Part of the Emotron manual attached.



Share this post

Link to post
Share on other sites

OK, that is a new, and quite proprietary way of dealing with floating points.  I don't know why they just didn't do what everyone else does and use two registers and regular IEEE floating point format....

You have to take the U16 value you get from the PLC and process it like they are floating point values in this weird format.  You can tell if they are floating point because the value returned will be > 32767.  

There is not a simple Conversion you can apply.  You would have to use script.  I'd probably either use the to.bit function to get the bits and then calculate it, or use some bitwise math to extract the proper values.  The tricky part is the sign, which is not in a usual place because the breaks aren't at 8 bit intervals.  You will likely need to experiment.


Share this post

Link to post
Share on other sites

Thank you for the info.


I was wondering that could you make me an example script to start the experimenting. 

Channel name =  shaft_power

Device type = Tamu1

D# = 1

Channel = 1004


I need the read the channel in standard 16 bit format and when I hit the 32767 (111111111111111) value I need to start the calculating after that. Is this correct?


Share this post

Link to post
Share on other sites

I'm afraid it would take a bit of experimentation so you are on your own.  But yes, if the value is less than or equal to 32767 you can just treat it as an integer and use it as is.  If it is > 32767 then you have to do the conversion.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now