You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Modbus process image in the memory of the <strong>COM462RTU</strong><br />
7.3.3 Reference value on channel 2<br />
The following reference value is stored in this channel: 12.34 A<br />
Word 0x14 0x15 0x16 0x17<br />
HiByte LoByte HiByte LoByte HiByte LoByte HiByte LoByte<br />
0x41 0x45 0x70 0xA4 0x00 0x03 0x00 0x4A<br />
Floating point value (Float) AT&T R&U Description<br />
12,34 No/No Ampere Overcurrent<br />
Tab. 7.5: Reference data stored in channel 2<br />
7.3.4 Explanation of how to access floating point values<br />
The test value 12.34 can be read out via Modbus/RTU using Modbus function<br />
0x03 at the address 0x0014. The test value has a size of 2 words.<br />
Proceed as follows:<br />
1. Determine the correct byte offset<br />
Interpreting both words as unsigned integer values should result in the<br />
following values:<br />
Word 1 with address 0x14: unsigned integer value => 16709 (0x4145)<br />
Word 2 with address 0x15: unsigned integer value => 28836 (0x70A4)<br />
2. Determine the correct byte resp. word swap<br />
There are four different combinations of swapping. The only correct<br />
value is 12.34.<br />
All swapping combinations are represented in the following table.<br />
<strong>COM462RTU</strong>_D00010_00_M_XXEN/07.2013<br />
43
Change language