Question about time

[fabrix76]

Hello David,
I'm approaching to analyze comtrade files using python and I have som dubs regarding time.

Looking row ad my .dat file, i see, in secon coloumn (timestamp) a progressive value incrementing always of the same quantity (625)
and I have 6405 samples.
Using library and loading data into dataframe i see that value became 0,000625 and last value is 4,002500
In .cfg file i can see start and end time, I undestand it is the time window of the sample (1 second of window in my case), so my sample rate shoud be 1 sec / 6405 samples and I was thinking that it correspond to each line increment (625) but it's wrong.

Can you help me to find where I'm wrong?

thank you in advance, for you good job and for the support

Regards

[xiiaochuang]

Hi there,

I have the same problem. After check through the code, I figure the time calculation for comtrade file with multiple sample rates is wrong.

python-comtrade/comtrade.py

Lines 1153 to 1154 in fd8a60f

	if sample_rate != 0.0:
	return (n - 1) / sample_rate

To fix it, I use the following code:

rec = comtrade.load(...)

time = []
val = 0
endsamp_ = 0
for samp, endsamp in rec.cfg.sample_rates:
    if endsamp > endsamp_:
        for i in range(endsamp_, endsamp):
            val += 1/samp
            val = round(val, 7)  # Handle precision loss for float numbers
            time += [val]
    endsamp_ = endsamp