def update_temp():
global ser, connected
if connected == 0:
top.after(
5000,
FindPort) # Not connected, try to reconnect again in 5 seconds
return
try:
strin = ser.readline(
) # Read the requested value, for example "+0.234E-3 VDC"
ser.readline() # Read and discard the prompt "=>"
if len(strin) > 1:
if strin[1] == '>': # Out of sync?
strin = ser.readline() # Read the value again
ser.write("MEAS1?\r\n") # Request next value from multimeter
except:
connected = 0
DMMout.set("----")
Temp.set("----")
portstatus.set("Communication Lost")
DMM_Name.set("--------")
top.after(5000, FindPort) # Try to reconnect again in 5 seconds
return
strin_clean = strin.replace(
"VDC",
"") # get rid of the units as the 'float()' function doesn't like it
if len(strin_clean) > 0:
DMMout.set(strin.replace("\r", "").replace(
"\n", "")) # display the information received from the multimeter
try:
val = float(
strin_clean) * 1000.0 # Convert from volts to millivolts
valid_val = 1
except:
valid_val = 0
try:
cj = float(CJTemp.get(
)) # Read the cold junction temperature in degrees centigrade
except:
cj = 0.0 # If the input is blank, assume cold junction temperature is zero degrees centigrade
if valid_val == 1:
ktemp = round(kconvert.mV_to_C(val, cj), 1)
if ktemp < -200:
Temp.set("UNDER")
elif ktemp > 1372:
Temp.set("OVER")
else:
Temp.set(ktemp)
else:
Temp.set("----")
else:
Temp.set("----")
connected = 0
top.after(
500, update_temp
) # The multimeter is slow and the baud rate is slow: two measurement per second tops!
def data_gen():
t = data_gen.t
while True:
strin = ser.readline()
t += 1
val = float(strin)
# val/=1000
val *= 150
val /= 33000
val *= 3.3
cj = 0
val /= 255
val *= 1000
val = round(kconvert.mV_to_C(val, cj), 1)
val = int(val)
temp = str(val).zfill(4) + '\n'
ser.write(temp.encode('ascii'))
print(strin)
print(val)
val += 25
yield t, val
import kconvert
print("For 1 mV with cold junction at 24 C, temperature is:",
round(kconvert.mV_to_C(1, 24.0), 2), "C")
import kconvert
print("For 8.15 mV with cold junction at 22 C, temperature is:",
round(kconvert.mV_to_C(1, 22.0), 1), "C")