Logging

Logging messages from device

• Subscribe to BehaviorEvents
• Add a GroupBy(Bonsai.Harp) operator
• Add a MessageWriter operator. Set the FileName property to MyDevice.harp/Behavior.bin

Ask for a device register read-dump

It is critical that the messages logged from the device are sufficient to reconstruct its state history. For that to be true, we need to know the initial state of all registers. This can be asked via a special register in the protocol core: OperationControl. This register has a single bit that, when set, will trigger the device to send a dump all the values of all its registers.

• To the previous example, in a different branch:
• Add a Timer operator with its DueTime property set to 2 seconds. This will mimic the delayed start of an experiment.
• Add a CreateMessage(Bonsai.Harp) operator after the Timer
• Select OperationControlPayload under Payload. Depending on your use case, you might want to change some of the settings, but we recommend:
  • DumpRegisters set to True (Required for the dump)
  • Heartbeat set to True (Useful to know the device is still alive)
  • MuteReplies set to False
  • OperationLed set to True
  • OperationMode set to Active
  • VisualIndicator set to On
• Add a Multicast operator to send the message to the device

Important

In your experiments, always validate that your logging routine has fully initialized before requesting a reading dump from the device. Failure to do so may result in missing data.

Completing the logging pattern with the device.yml configuration file

In order to use harp-python data interface to its full extent, we need to provide a device.yml configuration file. This file will contain the device's register map, which is necessary to interpret the data logged from the device.

This file can be manually added to the root of the logged data folder, or it can be saved in Bonsai:

• To the previous examples, in a different branch:
• Add a DeviceMetadata(Harp.Behavior) operator
• Add a WriteAllText operator to save the metadata to a file named device.yml

We can wrap all the previous patterns in a single grouped node:

Stay tuned for updates as, while the logging spec has been defined, the Bonsai.Harp library will soon be updated to include operators to more easily implement these patterns!