IDL 101
FUNCTIONAL DESCRIPTION
50
HB_IDL101_E_V222.doc
Gantner Instruments Test & Measurement GmbH
A typical application for the Arithmetic Channel is e.g. the determination of a value that cannot be measured directly,
but which can be calculated from other values (e.g. power as a product of voltage and current). Or the arithmetic
channel is used for further mathematical preparation of a measuring signal, in order to obtain a particular desired
display format.
Special functions for their solution the commands are not sufficient, can be done by an application respectively user
specific download program for the
Datalogger IDL 101.
Notice
: The calculation time of an Arithmetic Variable is 0.6 ms. The overall calculation time is the sum of the times of
all operands in the formula plus 0.6 ms.
Remarks
:
Division
(
/
)
When dividing by zero, the positive full scale (+10
37
) will be assigned to the Arithmetic Variable if the
numerator is positive and the negative full scale (-10
37
)will be assigned if the numerator is negative.
Square Root (
sqrt
)
The square root of a negative number is zero.
Logarithm to Base e (
ln
)
This function determines the natural logarithm of a value to the base of e (
≈
2,71828). For a value
≤
0 the
negative full scale will be assigned to the Arithmetic Variable.
Logarithm to Base 10 (
log
)
This function determines the logarithm of a value to the base of 10. For a value
≤
0 the negative full scale
will be assigned to the Arithmetic Variable.
Integrator
(
integ
)
With this function the value of a variable will continuously be integrated, i.e. the value indicated after this
function will be added to the value of the Arithmetic Variable every second. The result value can be reset to
the actual value of the measured variable via the bus via a digital input or via every other variable. Writing
any value to the itegrator register resets it.
Differentiator
(
deriv
)
With this function a variable will be differentiated by time. The differential quotient will be created every
second.
Arc Functions (
sin, cos, tan
)
The arc values must be taken in radians (2
π
= 360°). If calculating the tangent, the positive full scale will be
assigned to the Arithmetic Variable for the arc value
π
/2 and the negative full scale for the arc value -
π
/2.
Reverse Functions for sin (
arcsin
), cos (
arccos
) und tan (
arctan
)
The results of the reverse functions are given in radians (2
π
= 360°). At the function arcsin the value
π
/2 will
be assigned to the Arithmetic Variable for a value > 1 and the value -
π
/2 will be assigned for a value < -1. At
the function arccos the value 0 will be assigned to the Arithmetic Variable for a value > 1 and the value -
π
will be assigned for a value < -1.
