modbus write registers

[Jaime Rodriguez]

I am succesfully using the Modbus Library vis to read some holding registers in a Honeywell UDC controller. However, I need to write to the set point registers

400107 and 400108 which is a floating point register. The Modbus vis only accept values in a high word and a low word, so how can I use these vis to write a value of 60.5, for example. In other words I need to know the equivalent of 60.5 in low and high words (16 bit).

When I read the registers I convert the high and low words to SGL precision, but I do not know how to do the reverse.

Any ideas??

[Karissa]

You can just use the split/join number functions and a type cast to convert back and forth.



Message Edited by Karissa on 08-03-2008 10:37 PM

[Karissa]

Ok I just tried it and it works in LabVIEW 8.5 but not in LabVIEW 8.2, I think there was a bug in the Typecast function in the earlier LV versions.

[Karissa]

Woops, it works in the older versions of LabVIEW if you change all the DBL data types to SGL.

[Jaime Rodriguez]

    Thanks a lot for your suggestion... It works excellent..

Thanka a million