Hach-Lange SC 200 Profibus network card User Manual - Manual (Page 11)

Table 4 Block 3 sc controller STATUS (continued)
Bit Status1 Note
4 Relay C on
5 Relay D on
6–15 Not used
sc controller values
The following list show the data definitions for the sc controller:
• The sc controller primary value shows the result of a calculation.
• The sc controller secondary value shows the 0–20 mA or the 4–20 mA
output from Channel 1.
• The sc controller tertiary value shows the 0–20 mA or the 4–20 mA
output from Channel 2.
IEEE 745 floating point definition
Profibus uses 32-bit single precision IEEE floating point definition. The
definition has twenty three bits for the mantissa and eight bits for the
exponent. There is one bit for the sign of the mantissa. Refer to
Floating
point definition .
Figure 3 Floating point definition
1 Sign bit 4 Exponent
2 Exponent 5 Mantissa
3 Mantissa
Word wise swapping
Byte order inside Profibus telegram shows swapped and normal byte
sequences. In word wise swapping, the third and fourth bytes are
interchanged in order with the first and second bytes. This results in a byte
order of 3 4 1 2.
Table 5 Byte order inside Profibus telegram
sc controller swapped sc controller normal
Byte T1 value 0 x 91 Byte T1 value 0 x 3F
Byte T2 value 0 x B9 Byte T2 value 0 x 67
Byte T3 value 0 x 3F Byte T3 value 0 x 91
Byte T4 value 0 x 67 Byte T4 value 0 x B9
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