Publish to a Channel Feed

Publish message to update multiple channel fields simultaneously with MQTT

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Topic

channels/<channelID>/publish

Description

channels/<channelID>/publish updates a channel feed by publishing a message to the specified topic. Replace <channelID> with your ThingSpeak channel ID. To learn more about configuring your channel, see Channel Properties. To update multiple parameters simultaneously, see Payload Parameters.

  • Add any necessary Payload Parameters.

  • Set the PUBLISH messages to have a QoS value of 0.

  • Set the connection RETAIN flag to 0 (off).

  • Set the connection CleanSession flag to 1 (true).

To learn more about these flags, see the MQTT v3.1.1 specification.

Input Arguments

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Channel ID for the publish target, specified as a positive integer.

Payload Parameters

Specify the optional payload parameters for the PUBLISH message as a string with Name=Value arguments, separated by &. For example: field1=100&field2=50&lat=30.61&long=40.35 If the parameter definition string contains any special characters, it must be URL (percent) encoded (application/x-www-form-urlencoded).

field1

Data to be entered in field 1 of a channel.

For example: field1=100

fieldx

Data to be entered in field x of a channel. Make sure the field is enabled in the channel settings.

For example: fieldx=100

x must be less than or equal to 8, the number of allowed fields.

lat

Location of your channel in the form of latitude.

For example: lat=10.45

long

Location of your channel in the form of longitude.

For example: long=35.4

elevation

Elevation of your channel from the ground level in meters.

For example: elevation=100

status

Status message of your channel.

For example: status=Message

created_at

Date of feed entry in ISO 8601 format.

For example: created_at=2014-12-31 23:59:59

Examples

Configure MQTT X to send a PUBLISH message to update a channel feed.

In the New Connection dialog, use the following connection settings, along with client ID, username, and password derived when the MQTT device was created in ThingSpeak:

Name: MyChanName
Client ID: ENTER_MQTT_DEVICE_CLIENT_ID
Host: mqtt://    mqtt3.thingspeak.com
Port: 1883
Username: ENTER_MQTT_DEVICE_USERNAME
Password: ENTER_MQTT_DEVICE_PASSWORD
Clean Session: true

In the Payload pane, use the following settings:

Topic: channels/33301/publish
Payload: field1=45&field2=60&status=MQTTPUBLISH

This PUBLISH message publishes a value of 45 to field1 and 60 to field2 of channel 33301, along with a status message MQTTPUBLISH.

See Also

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