ZES ZIMMER LMG450, User Manual

Page: 67 / 306

Z E S ZIMMER Electronic Systems GmbH Chapter 4
67
if (Uhigh==0)
Ulow=RngU:1;
fi
if (Uhigh<Utrms:1)
Uhigh=Utrms:1;
fi
if (Ulow>Utrms:1)
Ulow=Utrms:1;
fi
The first
if
condition is used for resetting the minimum value: With Reset it would be set to 0
which is not sufficient, because this is already the smallest TRMS value. So if the maximum
TRMS value is reset to 0.0, the minimum value is set to the range value which will not be
reached under proper conditions. The second and third condition compute the maximum and
minimum value and store them in the variables
Uhigh
and
Ulow
which can be read out in the
Custom menu.
4.4.4.2.12 Example 3: Calculating THD+N
You want to measure the total distortion factor including noise (THD+N) of the voltage of
channel 2:
THDN=sqrt((Utrms:2^2-Uh:2[1]^2)/Uh:2[1]^2);
Please note that this will only work in the harmonic mode, because
Uh:2[1]
is only calculated
there!
4.4.4.2.13 Example 4: Counting pulses
You want to count the number of current pulses of a battery above 3A (the pulse width has to
be bigger than twice the cycle time!)
ibat=abs(Idc:1);
if (ibat>3.0)
if (r == 0)
n=n+1;
r=1;
fi
fi
if (ibat < 3.0)
r=0;
fi
4.4.4.2.14 Example 5:Switching digital outputs, depending on harmonics
### Wave1 ###
if(Ih:1[1]>0.08) dout_on(1);
else dout_off(1);
fi
### Wave3 ###
if(Ih:1[3]>0.068) dout_on(2);
else dout_off(2);
fi
### Wave5 ###
if(Ih:1[5]>0.05) dout_on(3);
else dout_off(3);
fi
The digital outputs 1 to 3 are switched on if the corresponding harmonic 1 to 5 is bigger than a
defined value. In the other case the output is switched off.