Need precise timestamps along with each datapoint from the PQMS modules

[gitansh95]

@QuazarTech/support
The commit tag referring to this issue is : e9c9fa1
Link to file : https://github.com/vishnu2709/Qrius/blob/IV_script/user_scripts/time_resolved_IV.py

We have written a python script to set a DC Voltage on the XSMU, and then make multiple measurements of current using the function CM_getReading (filterLength=1) from /modules/xsmu/xsmu.py.

The code for the measurement :

    f = open("I-Data.txt", "a")
    for index in range(iterations):
        current = xsmu_driver.CM_getReading( filterLength = 1 )
        temperature = xtcon_driver.getSampleTemperature()
        f.write(str(current) + "," + str(temperature) + '\n')
    f.close()

We were able to make roughly one current measurement every 200 milliseconds (time measured approximately using the function time.strftime() from standard python library time), using the code below :

import time
    f = open("I-Data.txt", "a")
    for index in range(iterations):
        current = xsmu_driver.CM_getReading( filterLength = 1 )
        t = time.strftime('%H:%M:%S')
        f.write(str(current) + "," + t + '\n')    
    f.close()

But time stamps obtained this way include the time taken for the communication between the PQMS and the computer, and the time taken to execute any python instructions, etc.

We have obtained the following plot of Measured Current vs Number of Datapoints, for CM_RANGE_1mA on a 6.2 V Zener Diode forward biased using a Voltage Source with a value 0.67 V.

In the above plot we want to replace the X-Axis (Number of Datapoints) by the precise time stamp at which each datapoint was generated (ignoring the communication time with the computer, the python script execution time and other possible overheads).

[kchat79]

SMU does not have any internal clock. So it cannot provide any time stamp. The best bet is to capture system time before and after the call to CM_getReading function. Then take the mid-point.

…

On Mon, Jul 3, 2017 at 3:29 PM, gitansh95 ***@***.***> wrote: @QuazarTech/support <https://github.com/orgs/QuazarTech/teams/support> The commit tag reffering to this issue is : e9c9fa1 afa8994867 Link to file : https://github.com/vishnu2709/Qrius/blob/IV_script/user_ scripts/time_resolved_IV.py We have written a python script to set a DC Voltage on the XSMU, and then make multiple measurements of current using the function CM_getReading (filterLength=1) from /modules/xsmu/xsmu.py. The code for the measurement f = open("I-Data.txt", "a") for index in range(iterations): current = xsmu_driver.CM_getReading( filterLength = 1 ) temperature = xtcon_driver.getSampleTemperature() f.write(str(current) + "," + str(temperature) + '\n') f.close() We are able to make roughly one such measurement every 500 milliseconds. But this time includes the time taken for the communication between the PQMS and the computer, and the time taken to execute any python instructions, etc. We have obtained the following plot of Measured Current vs Number of Datapoints, for CM_RANGE_1mA on a 6.2 V Zener Diode forward biased using a Voltage Source with a value 0.67 V. [image: current_vs_datapoint_0 67v] <https://user-images.githubusercontent.com/16288407/27787624-09623496-6003-11e7-83e2-2a0a6d9c80e8.png> In the above plot we want to replace the X-Axis (Number of Datapoints) by the precise time stamp at which each datapoint was generated (ignoring the communication time with the computer, the python script execution time and other possible overheads). — You are receiving this because you are on a team that was mentioned. Reply to this email directly, view it on GitHub <#1>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AZkf6INwaVO6G7mD9GWfYbuif1xkk83zks5sKLuXgaJpZM4OME-2> .

-- Dr. Krishnendu Chatterjee IIT Delhi India

[gitansh95]

@kchat79 Can you provide us with a function that streams data faster from the PQMS, something of the form getReading() that returns (data, dt, time_interval), where data is the datapoint, time_interval is the time interval of acquisition, and dt is the time duration of acquisition of each datapoint.