FDwfDeviceOpen disables power supply on Analog Discovery 2

[DurandA]

I am trying to automate some tests using different supply voltages.

First, I am using dwfcmd to set a voltage during the setup phase:

dwfcmd connect analogio channel=1 enable=1 voltage=1.15 masterenable=1 disconnect

Then I use a Python script to vary the voltage:

from dwfconstants import *

dwf = cdll.LoadLibrary("libdwf.so")
hdwf = c_int()

print("Opening first device")
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))

if hdwf.value == hdwfNone.value:
    print("failed to open device")
    quit()

time.sleep(5)

dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(True))
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(1), c_double(1.20))
dwf.FDwfAnalogIOEnableSet(hdwf, c_int(True))

However, calling FDwfDeviceOpen() disables the power supply. In the example above, I inserted a 5 sec sleep, which means there is no power during more than 5 seconds.

How can access the Analog Discovery 2 from Python without disabling the power supply?

Edit: I tried to remove disconnect from dwfcmd args and reuse the hdwf handle which just seems to be the enumeration id (always 1 in my case). However, the last line of dwfcmd.cpp is FApi("FDwfDeviceCloseAll", FDwfDeviceCloseAll());. I tried recompiling dwfcmd without this line using "g++ -o dwfcmd_noclose -I/usr/include/digilent/waveforms/ dwfcmd.cpp -ldwf" but once compiled it fails:

pure virtual method called
terminate called without an active exception
Aborted (core dumped)

It seems that this error happens whenever FDwfDeviceClose is not called, including outside of dwfcmd.

Edited July 27, 2021 by DurandA

[attila]

Hi @DurandA

Use the following in all apps and scripts using the device:

...
dwf.FDwfParamSet(DwfParamOnClose, c_int(0)) # 0 = run, 1 = stop, 2 = shutdown
dwf.FDwfDeviceOpen(...
dwf.FDwfDeviceAutoConfigureSet(hdwf, c_int(0)) # 0 = the device will be configured only when calling FDwf###Configure
...
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(True))
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(1), c_double(1.20))
dwf.FDwfAnalogIOEnableSet(hdwf, c_int(True))
dwf.FDwfAnalogIOConfigure(hdwf)
...
dwf.FDwfDeviceClose...

 

[DurandA]

Hi @attila

Unfortunately your solution does not work. The power supply still shuts down during the second FDwfDeviceOpen() for about 1 second. Here is a minimal script to reproduce the issue:

from ctypes import *
from dwfconstants import *

dwf = cdll.LoadLibrary("libdwf.so")
hdwf = c_int()

dwf.FDwfParamSet(DwfParamOnClose, c_int(0))
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))
dwf.FDwfDeviceAutoConfigureSet(hdwf, c_int(0))
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(True))
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(1), c_double(1.15))
dwf.FDwfAnalogIOEnableSet(hdwf, c_int(True))
dwf.FDwfAnalogIOConfigure(hdwf)
dwf.FDwfDeviceClose(hdwf)
# start over
dwf.FDwfParamSet(DwfParamOnClose, c_int(0))
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf)) # power shut down during ~ 1 sec
dwf.FDwfDeviceAutoConfigureSet(hdwf, c_int(0))
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(True))
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(1), c_double(1.15))
dwf.FDwfAnalogIOEnableSet(hdwf, c_int(True))
dwf.FDwfAnalogIOConfigure(hdwf)
dwf.FDwfDeviceClose(hdwf)

Thank you for your help.

[attila]

Hi @DurandA

I don't notice any shutdown with latest WF version 3.16.3 or 3.16.31
https://reference.digilentinc.com/reference/software/waveforms/start
https://forum.digilentinc.com/topic/8908-waveforms-beta-download/

 

from ctypes import *
import sys
import time
from dwfconstants import *

if sys.platform.startswith("darwin"):
    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")
else:
    dwf = cdll.LoadLibrary("dwf")

hdwf = c_int()

dwf.FDwfParamSet(DwfParamOnClose, c_int(0))

for i in range(10):
    dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))
    if hdwf.value == 0:
        print("failed to open device")
        szerr = create_string_buffer(512)
        dwf.FDwfGetLastErrorMsg(szerr)
        print(str(szerr.value))
        quit()

    dwf.FDwfDeviceAutoConfigureSet(hdwf, c_int(0))
    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(1))
    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(1), c_double(1.0+i/2))
    dwf.FDwfAnalogIOEnableSet(hdwf, c_int(1))
    dwf.FDwfAnalogIOConfigure(hdwf)
    dwf.FDwfDeviceClose(hdwf)

 

from ctypes import *
import sys
import time
from dwfconstants import *

if sys.platform.startswith("darwin"):
    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")
else:
    dwf = cdll.LoadLibrary("dwf")


cDev = c_int()
dwf.FDwfEnum(0, byref(cDev))
if cDev == 0:
    print("no device detected")
    quit()

dwf.FDwfParamSet(DwfParamOnClose, c_int(0))

hdwf = c_int()

for i in range(10):
    dwf.FDwfDeviceOpen(c_int(0), byref(hdwf))
    if hdwf.value == 0:
        print("failed to open device")
        szerr = create_string_buffer(512)
        dwf.FDwfGetLastErrorMsg(szerr)
        print(str(szerr.value))
        quit()

    dwf.FDwfDeviceAutoConfigureSet(hdwf, c_int(0))
    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(1))
    dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(1), c_double(1.0+i/2))
    dwf.FDwfAnalogIOEnableSet(hdwf, c_int(1))
    dwf.FDwfAnalogIOConfigure(hdwf)
    dwf.FDwfDeviceClose(hdwf)

 

[DurandA]

Thank you for your help, this solved the issue.

I was running WaveForms 2.21.3 but was missing the Adept Linux runtime. I am surprised that it even worked without the package. Device discovery is also much faster now.

Thanks @attila!

[Mina Sameh]

Hi @attila , can I know how do you use the GUI and the script at the same time ?

Also I always get max 2.7 volt when reading power supply I am not sure why ?

 

Edited June 20, 2022 by Mina Sameh

[attila]

Hi @Mina Sameh

The AD2 power supplies have no reading/sense feature.

[Mina Sameh]

@attila I read it now from the analog channel 1 and it gives me max 2.7 , I meant if we can use python script and GUI at same time ( not internal script in tool ) can this be done ?

[attila]

Hi @Mina Sameh

No, only one application/script can be connected to one device at a time.