Page 1 of 1

Slow output voltage decays

Posted: Tue Sep 21, 2021 4:15 am
by Tzhang0904
Dear Red Pitaya community,
I'm new to Red Pitaya and still learning the basics. I followed the online guide to duplicate their results. I hooked up the output channel to an oscillocope to see the dynamics. However, when I was using the slow analog output and the GPIOs, the output voltage did not stay at the set points. Instead, the voltage decayed with a RC time about 20 ms. The slow analog input and digital input are working fine. I don't know if I have made some errors in my code or it is something else.
Please let me know if you could shed some light on this matter.
Thank you so much!

I have my code attached here:

#!/usr/bin/python

import sys
import time
import redpitaya_scpi as scpi
import numpy as np
import random

rp_s = scpi.scpi(sys.argv[1])


period = 0.1 # seconds
i=0

while (i<=10):
rp_s.tx_txt('DIG:PIN:DIR OUT,DIO7_N')
rp_s.tx_txt('DIG:PIN DIO7_N,1')
rp_s.tx_txt('DIG:PIN LED0,1')
time.sleep(period)
rp_s.tx_txt('DIG:PIN LED0,0')
rp_s.tx_txt('DIG:PIN DIO7_N,0')
print ("Blinking LED["+str(led)+"]")
time.sleep(period)
i+=1

rp_s.close()

Re: Slow output voltage decays

Posted: Mon Oct 04, 2021 12:43 pm
by redpitaya
Thank you for your post.
Please note that the slow analog inputs are not suitable for data acquisition. They are good for monitoring.
More technical details are here https://redpitaya.readthedocs.io/en/lat ... xtent.html