Plc Path; Sync Time With Plc; Status Print Interval; Tags - ProSoft Technology MVI69E-LDM-MQTT Quick Start Manual

MVI69E-LDM-MQTT ♦ MQ Telemetry Transport
CompactLogix® Platform

9.1.2 PLC Path

This defines the connection string to connect to the PLC.

9.1.3 Sync Time with PLC

A flag indicating if the system time should be synchronized with the PLC.
Value
0
1
2

9.1.4 Status Print Interval

This setting is optional.
The MQTT broker periodically checks the connection status. Messages are written to the
log system on every status change. Additional status messages are written at the
interval defined in this parameter, whether or not the status has changed.
The default value is 10 (seconds).

9.1.5 Tags

The following table includes tags that are defined in the PLC with the settings to map
them to MQTT messages:
Parameter
Tag
DataType
ScanRate
Access
Topic
Subscribe Topic
ProSoft Technology, Inc.
Description
Default value. Synchronize once, if current system year is less than 2019, which is usually case
after system restart. This helps prevent a system reset when PLC time is not set.
Synchronize one time after the first successful connection to the PLC.
Synchronize after every successful connection to the PLC.
Description
Name of the tag in PLC. Defined for MVI69E-LDM only.
Data Type of the tag in the PLC. Possible values are: BOOL, SINT, INT, DINT, LINT, USINT,
UINT, UDINT, ULINT, REAL, LREAL, BYTE, WORD, DWORD, LDWORD, STRING82
Defines how often the tag value is read from the PLC, in milliseconds.
Defines if the tag is read-only (value is RD), or readable and writable (value is RDWR).
Name of the MQTT topic to which the MQTT-LDM subscribes. The MQTT-LDM will receive
messages on this topic and publish the appropriate data values to the PLC.
Optional. Ignored if the Access field is set to RD (read only). If this option is omitted, or has
an empty value, the system uses the same topic used for publishing. In this case, the MQTT-
LDM receives its own Publish messages as well. Although the received value is written only
if it is different than the last read value, there is no guarantee that an older value is not
written due to race conditions. It is recommended to use a different Subscribe Topic name,
rather than a Publish Topic name.
In the sample configuration files, the Subscribe Topic name is composed by adding /Set at
the end of the topic name.
Configuration File Details
Quick Start Guide
Page 44 of 54