Triggers from a JSON file¶

This tutorial will provide an example of saving and subsequently loading a Trigger object from a JSON file.

Initialize Runtime¶

To start, we'll import Acquire and create a Runtime object, which coordinates the streaming process.

import acquire
runtime = acquire.Runtime()

Create a Trigger Object¶

Trigger objects have 4 attributes: edge, enable, line, and kind. In this example, will only adjust the edge attribute.

# Instantiate a Trigger object
trig = acquire.Trigger()

# change the edge attribute from the default Rising to Falling
trig.edge = acquire.TriggerEdge.Falling

Save Properties to a JSON file¶

We'll utilize the json library to write our Trigger to a JSON file to save for subsequent acquisition.

import json

# cast the properties to a dictionary
trig = trig.dict()

# convert the dictionary to json with "human-readable" formatting
trig = json.dumps(trig, indent=4, sort_keys=True)

# save the trigger to file "sample_trig.json" in the current directory
with open("sample_trig.json", "w") as outfile:
    outfile.write(trig)

Example JSON file¶

The resulting sample_trig.json file is below:

{
  "edge": "Falling",
  "enable": false,
  "kind": "Input",
  "line": 0
}

Load Properties from a JSON file¶

You can load the trigger attributes in the JSON file to a Trigger object as shown below:

# Instantiate a `Trigger` object from the settings in sample_trig.json
trig = acquire.Trigger(**json.load(open('sample_trig.json')))

Download this tutorial as a Python script