WAGO 2789-9023, Руководство пользователя

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2789-9023 Fieldbus Description
Product manual | Version: 1.0.0 41
EtherNet/IP Communication Module
4.3 MQTT
“Message Queuing Telemetry Transport” (MQTT) defines an open network protocol that
is the preferred choice for exchanging data between IoT (“Internet of Things”) devices.
The product is an MQTT client that can be connected to a local broker.
The product supports the following features:
• MQTT protocol version: 3.1.1
• Quality of service level: 1
• Unencrypted port: 1883
• Encrypted port: 8883
• TLS version: 1.3
For configuration with a broker, see 8 Configuration of Communication with Broker
[ } 63] .
4.3.1 Connection Status
The following table shows the possible states of the connection status.
Table 50: MQTT Connection Status
Status Description Trigger (Preceding Action)
Disabled MQTT communication is disabled MQTT connection is configured to
Disable
Connecting Communication is being established MQTT connection is configured to
Enable
Connected Communication has been estab-
lished
No certificate found No certificate found for encrypted
communication Encrypted communication is started
even though no certificate has been
uploaded
Certificate verification failed Certificate verification failed An invalid certificate is uploaded or
is already in internal memory (may
be due to incorrect module time/
date)
New certificate detected, reboot re-
quired New certificate was detected, restart
required An existing certificate is replaced
with a new one and encrypted com-
munication is restarted
4.3.2 Data Exchange
Process data of a lower-level device can be read and written via the MQTT protocol. The
access operations can use JSON format or binary format. For the binary format, you can
choose between big-endian and little-endian.
In the following tables, the term “ value ” serves as a placeholder. When data is read out,
the current value appears.
The byte order depends on the data format selected.
The following process data can be read out in JSON format (communication module
“
Publish ” to the broker):
Table 51: Reading Out Process Data in JSON Format
No. Description JSON Format
1 Status of the connection to the
lower-level device "Module Status" : {
"Connection to device O.K." : "
value " }