Kipp&Zonen COMBILOG Data Logger - Manual (Page 53)

5.4 Arithmetic Channel
By means of the arithmetic channel sensor channels and con-
stants can be connected with each other via arithmetic opera-
tions. The result is allocated to the arithmetic channel. The for-
mula can contain up to 20 operands. The calculation is per-
formed with a stack depth of 20. The value is handled as a
4-byte floating point format with 24 significant bits according to
IEEE, standard 754. The full scale is –10
37 to +10 37 .
A typical application for the arithmetic channel is e.g. the de-
termination of a value that cannot be measured directly, but
calculated from other values (e.g. power as a product of
voltage and current). Or the arithmetic channel is used for fur-
ther mathematical preparation of a measuring signal, in order
to obtain a particular desired format, linearisation or similar.
Special functions for which the existing commands are not suf-
ficient, can be carried out by a user specific download program
for the COMBILOG 1022. For this case, some implemented
special functions can be used for assistance.
To integrate a serial channel the special function 1 is to be
used. The serial channel converts an ASCII telegram into a
float value. Two variants are possible to chose, constant length
or variable length. With constant length the conversion starts at
startposition and ends at startposition + length. With variable
length the conversion starts at startposition and ends at the first
delimiter character.
Should the conversion be unsuccessful the default value will be
taken.
The call to special function 1 is defined as:
Hardware Manual COMBILOG 1022
53