PMOD TC1 Sensor demonstration

This demonstration shows how to use the PmodTC1. You will also see how to plot a graph using matplotlib.

The PmodTC1 is required.

The thermocouple sensor is initialized and set to log a reading every 1 second. The temperature of the sensor can be changed by touching it with warm fingers or by blowing on it.

1. Use TC1 to read the current temperature

Connect the TC1 sensor to PMODB.



In [1]:

    
from pynq.overlays.base import BaseOverlay
base = BaseOverlay("base.bit")



In [2]:

    
from pynq.lib import Pmod_TC1

# TC1 sensor is on PMODB
my_tc1 = Pmod_TC1(base.PMODB)
print('Raw Register Value: %08x hex' % my_tc1.read_raw())
print('Ref Junction Temp:  %.4f' % my_tc1.read_junction_temperature())
print('Thermocouple Temp:  %.2f' % my_tc1.read_thermocouple_temperature())
print('Alarm flags:        %08x hex' % my_tc1.read_alarm_flags())









    



Raw Register Value: 014416b0 hex
Ref Junction Temp:  22.6875
Thermocouple Temp:  20.25
Alarm flags:        00000000 hex

2. Starting logging temperature once every second

Users can use set_log_interval_ms to set the time elapsed during 2 samples. By default it is set to 1 second.



In [3]:

    
my_tc1.start_log()

3. Modifying the temperture

Touch the thermocouple with warm fingers; or
Blow on the thermocouple with cool air

Stop the logging whenever you are finished trying to change the sensor's value.



In [4]:

    
my_tc1.stop_log()
log = my_tc1.get_log()

4. Plot values over time



In [23]:

    
%matplotlib inline
import matplotlib.pyplot as plt
from pynq.lib.pmod.pmod_tc1 import reg_to_tc
from pynq.lib.pmod.pmod_tc1 import reg_to_ref

tc = [reg_to_tc(v) for v in log]
ref = [reg_to_ref(v) for v in log]

plt.plot(range(len(tc)), tc, 'ro', label='Thermocouple')
plt.plot(range(len(ref)), ref, 'bo', label='Ref Junction')
plt.title('TC1 Sensor log')
plt.axis([0, len(log), min(tc+ref)*0.9, max(tc+ref)*1.1])
plt.legend()
plt.xlabel('Sample Number')
plt.ylabel('Temperature (C)')
plt.grid()
plt.show()



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