How to plot a deadband for a simple sine wave using python

Question

I am using the below codes so as to plot the dead band for a sine wave so that the dead band appears on the x axis as y=0. The output is minimized by the value of upper limit[y-0.5] and the lower limit.The dead band needs to be displayed here.Could any one help me in this.

import matplotlib.pyplot as plt
import numpy as np

UpperLimit = 0.5;
LowerLimit = -0.5;

x=np.linspace(-20,20,100);
y=np.sin(x);

if y < 0:
   y=np.sin(x)-LowerLimit
if y > 0:
   y=np.sin(x)-UpperLimit
else:
   y=0

plt.plot(x,y)
plt.grid()
plt.show()

MaxU - stand with Ukraine · Accepted Answer · 2016-03-17 15:05:49Z

1

I guess you should work with vectorized values, so try this

import matplotlib.pyplot as plt
import numpy as np

LL = -0.5
UL = 0.5

x=np.linspace(-20,20,100)
y=np.sin(x)

# plot original sine
plt.plot(x,y)


# zero output value for the dead zone
y[(y>=LL) & (y<=UL)] = 0

y[y>UL] -= UL
y[y<LL] -= LL

# plot "simulinked" ....
plt.plot(x,y)

plt.grid()
plt.show()

PS it would much easier to understand what you want if you would provide a link to the "Dead Zone" algorithm, because not all of us aware of it

edited Mar 17, 2016 at 15:05

answered Mar 17, 2016 at 14:07

MaxU - stand with Ukraine

212k37 gold badges402 silver badges437 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

MaxU - stand with Ukraine Over a year ago

do you have an algorithm, describing how should it be calculated?

HEMS Over a year ago

The output must be zero for certain x values in addition being symmetric about the x axis.The output is similar to that of the dead zone block used in Simulink.

HEMS Over a year ago

:Please consider the upper limit and the lower limit as the thresholds.The y value needs to exceed the threshold value so that the output value appears .When the y value is below the threshold ,the output appears as zero on x axis.The x values have no control over the dead band of the output value.The dead band is controlled by the value of upper limit and the lower limit.

HEMS Over a year ago

Ausgezeichnet.This is exactly what I was looking for.

pjbollinger · Accepted Answer · 2016-03-17 14:57:33Z

0

Instead of having an if statement acting on your array, you need to iterate through your array of y values and modify each one. Also, with an if statement of y > 0 or y < 0 will not achieve the deadband result you are looking for. Instead, you should use y > UpperLimit or y < LowerLimit

This should work:

import matplotlib.pyplot as plt
import numpy as np

UpperLimit = 0.5;
LowerLimit = -0.5;

x=np.linspace(-20,20,100);
y=np.sin(x);

for y_point in np.nditer(y, op_flags=['readwrite']):
    if y_point > UpperLimit:
        y_point[...] -= UpperLimit
    elif y_point < LowerLimit:
        y_point[...] -= LowerLimit
    else:
        y_point[...] = 0

plt.plot(x,y)
plt.grid()
plt.show()

answered Mar 17, 2016 at 14:57

pjbollinger

411 silver badge6 bronze badges

2 Comments

MaxU - stand with Ukraine Over a year ago

please do not iterate through numpy arrays, pandas data frames/series, other vectorized data unless it's absolutely necessary ...

pjbollinger Over a year ago

OK. Thank you for the tip. I didn't realize it can be done the way you did it. What is it called when you aren't iterating over the array? When you do this: y[y>something] = stuff

Collectives™ on Stack Overflow

How to plot a deadband for a simple sine wave using python

2 Answers 2

4 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related