Can't acuire images from an iDS CCD using pyueye

Question

• CCD: iDS UI-3140CP-M-GL Rev.2
• Python 3.8.19
• pyueye==4.96.952
• uEye Cockpit 4.96.0650

#Libraries
from pyueye import ueye
import numpy as np
import cv2
import sys

#---------------------------------------------------------------------------------------------------------------------------------------

#Variables
hCam = ueye.HIDS(0)             #0: first available camera;  1-254: The camera with the specified camera ID
sInfo = ueye.SENSORINFO()
cInfo = ueye.CAMINFO()
pcImageMemory = ueye.c_mem_p()
MemID = ueye.int()
rectAOI = ueye.IS_RECT()
pitch = ueye.INT()
nBitsPerPixel = ueye.INT(8)    #24: bits per pixel for color mode; take 8 bits per pixel for monochrome
channels = 1                    #3: channels for color mode(RGB); take 1 channel for monochrome
m_nColorMode = ueye.INT()       # Y8/RGB16/RGB24/REG32
bytes_per_pixel = int(nBitsPerPixel / 8)
#---------------------------------------------------------------------------------------------------------------------------------------
print("START")
print()


# Starts the driver and establishes the connection to the camera
nRet = ueye.is_InitCamera(hCam, None)
if nRet != ueye.IS_SUCCESS:
    print("is_InitCamera ERROR")

# Reads out the data hard-coded in the non-volatile camera memory and writes it to the data structure that cInfo points to
nRet = ueye.is_GetCameraInfo(hCam, cInfo)
if nRet != ueye.IS_SUCCESS:
    print("is_GetCameraInfo ERROR")

# You can query additional information about the sensor type used in the camera
nRet = ueye.is_GetSensorInfo(hCam, sInfo)
if nRet != ueye.IS_SUCCESS:
    print("is_GetSensorInfo ERROR")

nRet = ueye.is_ResetToDefault( hCam)
if nRet != ueye.IS_SUCCESS:
    print("is_ResetToDefault ERROR")

# Set display mode to DIB
nRet = ueye.is_SetDisplayMode(hCam, ueye.IS_SET_DM_DIB)

# Set the right color mode
if int.from_bytes(sInfo.nColorMode.value, byteorder='big') == ueye.IS_COLORMODE_BAYER:
    # setup the color depth to the current windows setting
    ueye.is_GetColorDepth(hCam, nBitsPerPixel, m_nColorMode)
    bytes_per_pixel = int(nBitsPerPixel / 8)
    print("IS_COLORMODE_BAYER: ", )
    print("\tm_nColorMode: \t\t", m_nColorMode)
    print("\tnBitsPerPixel: \t\t", nBitsPerPixel)
    print("\tbytes_per_pixel: \t\t", bytes_per_pixel)
    print()

elif int.from_bytes(sInfo.nColorMode.value, byteorder='big') == ueye.IS_COLORMODE_CBYCRY:
    # for color camera models use RGB32 mode
    m_nColorMode = ueye.IS_CM_BGRA8_PACKED
    nBitsPerPixel = ueye.INT(32)
    bytes_per_pixel = int(nBitsPerPixel / 8)
    print("IS_COLORMODE_CBYCRY: ", )
    print("\tm_nColorMode: \t\t", m_nColorMode)
    print("\tnBitsPerPixel: \t\t", nBitsPerPixel)
    print("\tbytes_per_pixel: \t\t", bytes_per_pixel)
    print()

elif int.from_bytes(sInfo.nColorMode.value, byteorder='big') == ueye.IS_COLORMODE_MONOCHROME:
    # for color camera models use RGB32 mode
    m_nColorMode = ueye.IS_CM_MONO8
    nBitsPerPixel = ueye.INT(8)
    bytes_per_pixel = int(nBitsPerPixel / 8)
    print("IS_COLORMODE_MONOCHROME: ", )
    print("\tm_nColorMode: \t\t", m_nColorMode)
    print("\tnBitsPerPixel: \t\t", nBitsPerPixel)
    print("\tbytes_per_pixel: \t\t", bytes_per_pixel)
    print()

else:
    # for monochrome camera models use Y8 mode
    m_nColorMode = ueye.IS_CM_MONO8
    nBitsPerPixel = ueye.INT(8)
    bytes_per_pixel = int(nBitsPerPixel / 8)
    print("else")

# Can be used to set the size and position of an "area of interest"(AOI) within an image
nRet = ueye.is_AOI(hCam, ueye.IS_AOI_IMAGE_GET_AOI, rectAOI, ueye.sizeof(rectAOI))
if nRet != ueye.IS_SUCCESS:
    print("is_AOI ERROR")

width = rectAOI.s32Width
height = rectAOI.s32Height

# Prints out some information about the camera and the sensor
print("Camera model:\t\t", sInfo.strSensorName.decode('utf-8'))
print("Camera serial no.:\t", cInfo.SerNo.decode('utf-8'))
print("Maximum image width:\t", width)
print("Maximum image height:\t", height)
print()

#---------------------------------------------------------------------------------------------------------------------------------------

# Allocates an image memory for an image having its dimensions defined by width and height and its color depth defined by nBitsPerPixel
nRet = ueye.is_AllocImageMem(hCam, width, height, nBitsPerPixel, pcImageMemory, MemID)
if nRet != ueye.IS_SUCCESS:
    print("is_AllocImageMem ERROR")
else:
    # Makes the specified image memory the active memory
    nRet = ueye.is_SetImageMem(hCam, pcImageMemory, MemID)
    if nRet != ueye.IS_SUCCESS:
        print("is_SetImageMem ERROR")
    else:
        # Set the desired color mode
        nRet = ueye.is_SetColorMode(hCam, m_nColorMode)



# Activates the camera's live video mode (free run mode)
nRet = ueye.is_CaptureVideo(hCam, ueye.IS_DONT_WAIT)
if nRet != ueye.IS_SUCCESS:
    print("is_CaptureVideo ERROR")

# Enables the queue mode for existing image memory sequences
nRet = ueye.is_InquireImageMem(hCam, pcImageMemory, MemID, width, height, nBitsPerPixel, pitch)
if nRet != ueye.IS_SUCCESS:
    print("is_InquireImageMem ERROR")
else:
    print("Press q to leave the programm")

#---------------------------------------------------------------------------------------------------------------------------------------

# Continuous image display
while(nRet == ueye.IS_SUCCESS):

    # In order to display the image in an OpenCV window we need to...
    # ...extract the data of our image memory
    array = ueye.get_data(pcImageMemory, width, height, nBitsPerPixel, pitch, copy=False)

    # bytes_per_pixel = int(nBitsPerPixel / 8)

    # ...reshape it in an numpy array...
    frame = np.reshape(array,(height.value, width.value, bytes_per_pixel))

    # ...resize the image by a half
    frame = cv2.resize(frame,(0,0),fx=0.5, fy=0.5)
    
#---------------------------------------------------------------------------------------------------------------------------------------
    #Include image data processing here

#---------------------------------------------------------------------------------------------------------------------------------------

    #...and finally display it
    cv2.imshow("SimpleLive_Python_uEye_OpenCV", frame)

    # Press q if you want to end the loop
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
#---------------------------------------------------------------------------------------------------------------------------------------

# Releases an image memory that was allocated using is_AllocImageMem() and removes it from the driver management
ueye.is_FreeImageMem(hCam, pcImageMemory, MemID)

# Disables the hCam camera handle and releases the data structures and memory areas taken up by the uEye camera
ueye.is_ExitCamera(hCam)

# Destroys the OpenCv windows
cv2.destroyAllWindows()

print()
print("END")

The above is an example script from the iDS official website. It does not has any error nor exception but I am unable to acquire correct images. Only I could see is black. The maximum value of frame is less than 4. It varies shot to shot but never exceed 4. I can get fine images via uEye Cockpit. What's wrong with the script? I can't find much information for this.