NI digital read task

Learn how to acquire digital data from NI devices with Synnax.

This task follows the standard task lifecycle.

Task configuration reference

Table

Parameter	Type	Required	Default	Description
`device`	string	Yes	-	Device key to read from
`sample_rate`	number	No	`10`	Samples per second (Hz)
`stream_rate`	number	No	`5`	Rate data is streamed to Synnax (Hz), must be ≤ `sample_rate`
`channels`	array	Yes	-	List of digital input channel configurations

Channel configuration reference

DI Channel NI-DAQmx C API Reference

Table

Parameter	Type	Required	Default	Description
`channel`	number	Yes	-	Synnax channel key for digital input data
`port`	number	Yes	-	Physical port
`line`	number	Yes	-	Line number on the port

Important rules

One task per module -> Only one running task can claim a module at a time.
Stream rate -> For sample rates under 50 Hz, set the stream rate equal to the sample rate. Above that, keep the stream rate under 50 Hz.

How-to

Console

Python

TypeScript

Configure and run task

import synnax as sy
from synnax import ni

client = sy.Synnax()

# Retrieve device
digital_dev = client.devices.retrieve(name="Mod1_Digital")

# Create index channel
di_time = client.channels.create(
    name="di_time",
    is_index=True,
    data_type=sy.DataType.TIMESTAMP,
    retrieve_if_name_exists=True,
)

# Create data channels
di_0_0 = client.channels.create(
    name="di_0_0",
    index=di_time.key,
    data_type=sy.DataType.UINT8,
    retrieve_if_name_exists=True,
)
di_0_1 = client.channels.create(
    name="di_0_1",
    index=di_time.key,
    data_type=sy.DataType.UINT8,
    retrieve_if_name_exists=True,
)
di_1_0 = client.channels.create(
    name="di_1_0",
    index=di_time.key,
    data_type=sy.DataType.UINT8,
    retrieve_if_name_exists=True,
)

# Create and configure task
task = ni.DigitalReadTask(
    name="NI Digital Read Task",
    device=digital_dev.key,
    sample_rate=sy.Rate.HZ * 100,
    stream_rate=sy.Rate.HZ * 25,
    channels=[
        ni.DIChannel(
            channel=di_0_0.key,
            port=0,
            line=0,
        ),
        ni.DIChannel(
            channel=di_0_1.key,
            port=0,
            line=1,
        ),
        ni.DIChannel(
            channel=di_1_0.key,
            port=1,
            line=0,
        ),
    ],
)

client.tasks.configure(task)

# Start task and read data
with task.run():
    with client.open_streamer(["di_0_0", "di_0_1", "di_1_0"]) as streamer:
        for _ in range(10):
            frame = streamer.read()
            print(frame)

Edit task configuration

# Retrieve existing task
task = client.tasks.retrieve(name="NI Digital Read Task")
task = ni.DigitalReadTask(internal=task)

# Update task-level configuration
task.config.auto_start = True
task.config.stream_rate = int(sy.Rate.HZ * 50)

# Update first channel configuration
task.config.channels[0].port = 0
task.config.channels[0].line = 2

# Update second channel configuration
task.config.channels[1].port = 0
task.config.channels[1].line = 3

# Update third channel configuration
task.config.channels[2].port = 1
task.config.channels[2].line = 1

# Apply changes
client.tasks.configure(task)

Configure and run task

import { Synnax } from "@synnaxlabs/client";

const client = new Synnax();

// Retrieve device
const [digitalDev] = await client.devices.retrieve({ names: ["Mod1_Digital"] });

// Create index channel
const diTime = await client.channels.create(
  {
    name: "di_time",
    isIndex: true,
    dataType: "timestamp",
  },
  { retrieveIfNameExists: true },
);

// Create data channels
const di00 = await client.channels.create(
  {
    name: "di_0_0",
    index: diTime.key,
    dataType: "uint8",
  },
  { retrieveIfNameExists: true },
);

const di01 = await client.channels.create(
  {
    name: "di_0_1",
    index: diTime.key,
    dataType: "uint8",
  },
  { retrieveIfNameExists: true },
);

const di10 = await client.channels.create(
  {
    name: "di_1_0",
    index: diTime.key,
    dataType: "uint8",
  },
  { retrieveIfNameExists: true },
);

// Create and configure task
const task = await client.tasks.create({
  name: "NI Digital Read Task",
  rack: digitalDev.rack,
  type: "ni_digital_read",
  config: {
    device: digitalDev.key,
    sampleRate: 100,
    streamRate: 25,
    channels: [
      {
        channel: di00.key,
        port: 0,
        line: 0,
      },
      {
        channel: di01.key,
        port: 0,
        line: 1,
      },
      {
        channel: di10.key,
        port: 1,
        line: 0,
      },
    ],
  },
});

// Start task
await task.start();

// Read data
const streamer = await client.openStreamer(["di_0_0", "di_0_1", "di_1_0"]);
for (let i = 0; i < 10; i++) {
  const frame = await streamer.read();
  console.log(frame);
}

// Stop task
await task.stop();
await streamer.close();

Edit task configuration

import { ni } from "@synnaxlabs/client";

// Retrieve existing task
const task = await client.tasks.retrieve({ name: "NI Digital Read Task" });

// Parse and update configuration
const config = ni.digitalReadConfigZ.parse(task.config);

// Update task-level configuration
config.autoStart = true;
config.streamRate = 50;

// Update first channel configuration
config.channels[0].port = 0;
config.channels[0].line = 2;

// Update second channel configuration
config.channels[1].port = 0;
config.channels[1].line = 3;

// Update third channel configuration
config.channels[2].port = 1;
config.channels[2].line = 1;

// Apply changes
await client.tasks.create({
  key: task.key,
  rack: task.rack,
  name: task.name,
  type: task.type,
  config,
});

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