Global diagnostic items

<ItemName>

DataType

Read/ Write

Subscriber/Publisher Availability

Description

BrokerAddress

String

R

Both

Displays the IP address and port number of the MQTT broker or host name that was configured while connecting to the broker.

Example: 127.0.0.1:1883,
where 127.0.0.1 is the IP address and 1883 is the port number.

ClientId

String

R

Both

Displays the unique identifier of the MQTT subscriber/publisher client connection to the broker. Each connection to the broker is assigned a unique ID during the broker or publisher configuration.

PersistSession

Bool

R

Both

Displays 'True' or 'False' based on whether the Persist Session checkbox was enabled during the MQTT broker configuration. When enabled, the broker stores any QoS1 or QoS2 messages that have not been retrieved.

PayloadType

String

R

Both

Displays the format of the message payload. For the subscriber, the value can be either JSON or JSON_Sparkplug. For the publisher, the value can be JSON-VTQ1, JSON-VTQ2, or Sparkplug.

ServerCertificateExpiryDate

VT_DATE

(DateTime)

R

Both

Displays the TLS Certificate expiry date of the MQTT broker. If TLS is not used, then value is initialized to 01/01/1970 00:00:00 AM and Quality = 0x20.

ServerCertificateSubject

String

R

Both

Displays the TLS Certificate subject of the MQTT broker. If TLS is not used, then the value is initialized to an empty string.

ClientCertificateExpiryDate

VT_DATE

(DateTime)

R

Both

Displays TLS Certificate expiry date of the MQTT client. If TLS is not used, then value is initialized to 01/01/1970 00:00:00 AM and Quality = 0x20.

ClientCertificateSubject

String

R

Both

Displays TLS Certificate subject of the MQTT client. If TLS is not used, then the value is initialized to empty string.

IsAnonymous

Bool

R

Both

Displays 'True' if user credentials are not provided while configuring the broker. Empty if the user credentials are provided.

UserName

String

R

Both

Displays the user credentials provided while configuring the broker. (Empty if IsAnonymous=True)

StartDateTime

VT_DATE

(DateTime)

R

Both

Displays the Date and Time when the MQTT Communication Driver was started.

UpTime

Int64

(DateTime)

R

Both

Displays the elapsed time in seconds since the MQTT Communication Driver was started.

ConnectionEvents

Int32

R

Both

Displays the number of times the MQTT publisher/subscriber connects to the MQTT broker.

LastConnectTime

VT_DATE

(DateTime)

R

Both

Displays the time when the last connection of the MQTT subscriber/publisher to the broker was successful.

LastDisconnectTime

VT_DATE

(DateTime)

R

Both

Displays the time when the MQTT subscriber/publisher last disconnected from the broker.

SubscribedItemCount

Int32

R

Subscriber only

Displays the total number of subscribed items under the broker.

PublishedItemCount

Int32

R

Publisher only

Displays the total number of published items under the broker.

LastPublishTime

VT_DATE

(DateTime)

R

Both

Displays the time when the last message was published in the broker. Default value is 01/01/1970 00:00:00 AM and Quality = 0x20

TotalReadErrors

Int32

R

Subscriber only

Displays the total number of failed read operations in all connections since the MQTT Communication Driver was started or last reseted. (An error is counted if one or more item reads failed, or the entire read is not executed).

TotalWriteErrors

Int32

R

Both

Displays the total number of failed write operations in all connections since the MQTT Communication Driver was started or last reseted. (An error is counted if one or more item writes failed, or the entire write is not executed)

TotalPublishErrors

Int32

R

Publisher only

Displays the total number of failed publish operations in all connections to the broker since the MQTT Communication Driver was started or last reseted.

ResetTotals

Bool

RW

Both

Displays 'True' or 'False' based on whether there was a reset of the values of the following system items: TotalReadItemErrors,
TotalWriteItemErrors, ConnectionEvents,

TotalDataMessagesPublished,
CumulativeBytesSent and CumulativeBytesReceived.

Default value: False

LastPayloadSizeIncoming

Int32

R

Mainly for Subscriber

Displays the length of incoming buffer in the response from the MQTT broker.

LastPayloadSizeOutgoing

Int32

R

Both

Displays the length of outgoing buffer in the request from the MQTT Communication Driver.

CumulativeBytesReceived

Int64

R

Mainly for Subscriber

Displays the cumulative count of total bytes received from MQTT broker since the driver was started or last reseted (aggregate of LastPayloadSizeIncoming).

CumulativeBytesSent

Int64

R

Both

Displays the cumulative count of total bytes sent to MQTT broker since the driver was started or last reseted (aggregate of LastPayloadSizeOutgoing).

StoreAndForwardActive

Bool

R

Publisher only

Displays 'True' or 'False' based on whether the Enable Store and Forward checkbox was enabled during publisher configuration.

If the value is 'True', there is an outage in the connection to the MQTT broker. Publishing data is being stored locally and will be sent once the connection is up.

If this value is 'False', the MQTT Communication Driver is publishing data directly to the MQTT broker.

TotalPublishingDevices

Int32

R

Publisher only

Displays the total number of publishing devices connected to the broker.

TotalDataMessagesPublished

Int32

R

Publisher only

Displays the total umber of data messages published since MQTT Communication Driver the driver was started or last reseted.

Run

Bool

RW

Both

Displays 'True' (non-zero) if the system items calculation and reporting is enabled. True is the default value.
Displays 'False' if the system items calculation and reporting is disabled.
The quality of system items is set to 0x14 (LAST KNOWN VALUE) if the system item reporting is not enabled.