AccessException on cam.SequencerSetNext.GetValue()

[SpangeJ]

Hello,

I have an application running three cameras using Sequencer. It is 2x acA1300-200um and 1x a2A5320-23ucPRO (FW 2.3.0 which supports Sequencer)

In my code I can access cam.SequencerSetNext.GetValue() for my first two acA cameras, but when I try to run it on the a2A I get the following error:

Traceback (most recent call last): File "<input>", line 1, in <module> cam.SequencerSetNext.GetValue() File "/opt/optoscale/venvs/fishrecording/lib/python3.6/site-packages/pypylon/genicam.py", line 2162, in GetValue return _genicam.IInteger_GetValue(self, Verify, IgnoreCache) _genicam.AccessException: Node is not readable. : AccessException thrown in node 'SequencerSetNext' while calling 'SequencerSetNext.GetValue()' (file 'IntegerT.h', line 149)

I know the object is there, see (this is bpdb):

Why can I not access the node?

[SMA2016a]

have you set configuration mode to on?

camera.Open() camera.SequencerConfigurationMode.SetValue('On'); val = camera.SequencerSetNext.GetValue() print(val)

[SpangeJ]

@SMA2016a thank I'll try this out. So I have a verry large script, but this is the essence:

Class Camera:
def connect(self):
# Sequencer mode
    logger.debug('SequencerMode On! Sequence length: {}'.format(self.seq_len))
    cam.GainAuto = "Off"
    cam.ExposureAuto = 'Off'
    cam.SequencerMode = 'Off'
    cam.SequencerConfigurationMode = 'On'
    for j in range(self.seq_len):
        cam.SequencerSetSelector = j
        cam.ExposureTime = exposure[j]
        cam.Gain = gain[j]
        cam.SequencerSetSave.Execute()
    cam.SequencerSetNext = 0
    cam.SequencerSetStart = 0
    cam.SequencerSetSave.Execute()
    cam.SequencerConfigurationMode = 'Off'
    cam.SequencerMode = 'On'
    logger.info('Sequencer camera {}: exposure: {}, gain = {}'.format(i, exposure, gain))

def ensure_start_of_sequence(self):
    for i, cam in enumerate(self.camera):
        if cam.SequencerSetNext.Value != 0:
            logger.error('Cam {}: Sequencer out of sync!. Restart SW!'.format(i))

I.E. I connect to the cameras, then I send N trigger signals and acquire N images, and since the length of my sequencer is N, I expect to have looped through the set on all my cameras. However, I would like to verify that by checking. And this works if my cameras are acA, but not a2A.

Are you telling me that I have to alter ensure_start_of_sequence to:

def ensure_start_of_sequence(self):
    for i, cam in enumerate(self.camera):
        if 'a2A' in cam.DeviceModelName.Value:
            cam.SequencerConfigurationMode.SetValue('On');
        if cam.SequencerSetNext.Value != 0:
            logger.error('Cam {}: Sequencer out of sync!. Restart SW!'.format(i))
        if 'a2A' in cam.DeviceModelName.Value:
            cam.SequencerConfigurationMode.SetValue('Off');

NB! Remember, that at this stage cam.SequencerMode = 'On'

[thiesmoeller]

Ace2 has some slightly more modern sequencer config. ( we updated to latest genicam spec )

We'll provide a pypylon sample for ace2 sequencer in the next week

[SpangeJ]

@thiesmoeller

I have a reproducible bug now that I would like your help with, How to reproduce:

1. My application crashes on the error explained in this thread _genicam.AccessException: Node is not writable : AccessException thrown in node 'SequencerConfigurationMode' while calling 'SequencerConfigurationMode.FromString()'
2. I re-run the script and then I get the following error: cam.Open() File /pypylon/pylon.py, line 3308, in Open return _pylon.InstantCamera_Open(self) _genicam.RuntimeException: Could not apply configuration. Pylon::GenericException caught in OnOpened method msg=Node is not writable : AccessException thrown in node 'TriggerMode' while calling 'TriggerMode.FromString()' (file 'ValueT.h', line 85) : RuntimeException thrown (file 'AcquireContinuousConfiguration.h', line 76)

I am able to resolve this, but that is a manual job where I open Pylon Viewer, connect to the cameras and select "Device control" --> "Device reset" --> "Execute". The camara disappears and reappears after about five seconds. How do I resolve this error with .Open() in a script?

[thiesmoeller]

The camera state stays on USB and GEV even if you shutdown the application.

I assume the camera ist still in sequencer mode.

Just disable it

[SpangeJ]

@thiesmoeller Also, Device reset is buggy I have three cameras, but after Device Reset, only two comes back. Rebooting the system makes my three cameras re-appear:

[thiesmoeller]

What is your platform and OS version ? What does dmesg say?

[SpangeJ]

@thiesmoeller I can reproduce the issue, not consistently, but If I try Device Reset (after connecting) in Pylon Viewer multiple times I can reproduce it.

This is interesting:

I ran dmesg -wH dmesg.txt is the output.

PylonViewer:

OS:

[SpangeJ]

@thiesmoeller

Ace2 has some slightly more modern sequencer config. ( we updated to latest genicam spec ) We'll provide a pypylon sample for ace2 sequencer in the next week

What is the status this?

[thiesmoeller]

https://github.com/basler/pypylon-samples/blob/main/notebooks/Ace2_USB_hdr_exposure_bracketing_using_sequencer.ipynb

[SpangeJ]

@thiesmoeller thank you I'll have a look at this ASAP

[SpangeJ]

Just by reading the documentation it looks like sequence_id_chunk = res.ChunkDataNodeMap.ChunkSequencerSetActive.Value will solve the issue I address here. I will test it out within, and you will here from me next week.

Thank you verry much, @thiesmoeller

[SpangeJ]

@thiesmoeller Thank you for the documentation, I can confirm what the issue is resolved.