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Connect IoT - MQTT Driver#

MQTT is a machine-to-machine (M2M)/Internet of Things connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport.

Data Types#

These are the supported specific data types:

Name Description
UInt8 Unsigned Integer 8 bits
UInt16 Unsigned Integer 16 bits
UInt32 Unsigned Integer 32 bits
Int8 Signed Integer 8 bits
Int16 Signed Integer 16 bits
Int32 Signed Integer 32 bits
Float Floating number
Double Floating double-precision number
String ASCII value (text string)

Protocol Parameters#

The protocol supports the following parameters:

Name Type Possible Values Default Value Description
address String Address of MQTT broker
port Integer 1883 Port of MQTT broker
user String Login Username
password String Login Password
pollInterval Integer 2000 Time between variable polling when no change value notification is available. Only used in events. (milliseconds)
byteOrder Enum BigEndian
LittleEndian		 BigEndian Byte order of the data of the message
Convert Non Printable ASCII Chars On Send Boolean False Does character substitution on values sent. Replaces ASCII name tokens with the correspondent ASCII value.(e.g.: <NUL> to #00, ..., <DEL> to #127, on command values)
Convert Non Printable ASCII Chars On Receive Boolean False Does character substitution on values received. Replaces non printable ascii codes to correspondent <NAME>.(e.g.: #00 to <NUL>, #01 to <SOH>,...,#7F to <DEL>)

Extended Parameters#

Property#

Name Type Possible Values Default Value Description
identifierType Enum None
RegularExpression
Token		 None Method used to identify a property. Must be one of: None, RegularExpression or Token. If None is used, Identifier Value will be ignored and all messages will update that property. Token type will match the Identifier Value text only on the beginning of the message and RegularExpression will match on configured Regular Expression Identifier Value field.
identifierValue String Value of the Property Identifier. Valid on RegularExpression or Token Identifier Type. Non printable ASCII character may be converted if Convert Non Printable ASCII Chars on Identifiers option is used
Convert Identifier Non Printable ASCII Chars Replaces non printable ascii codes with <NAME> to correspondent ascii code (e.g., <NULL> to #0, <SOH> to #1, <STX> to #2, ..., <US> to #31, <DEL> to #127

Event#

Name Type Possible Values Default Value Description
triggerMode Enum Always
OnChange
OnInterval		 Always Data can be published (event based):
Always: every time the trigger property value is received
OnChange: every time a different trigger property value is received
OnInterval: On a periodic basis (every periodic interval, in milliseconds), disregarding property update cycles or values
interval Integer 1000 Number of milliseconds to publish data. Only valid on triggerMode OnInterval

Event Property#

Name Type Possible Values Default Value Description
isTrigger Boolean true Trigger the event when the property is received (event triggerMode Always), or when the value is changed (event triggerMode OnChange)

Remarks/Behavior#

  • When an event has more than one property with the isTrigger flag:
  • It will be triggered every time any of the properties value changes.
  • The value of the other properties will be requested at that time.
  • It is possible to have multiple triggers with the same set values (because they have not changed). If this behavior is not intended, separate into multiple events each one with its own trigger set.
  • When an event has no property with the isTrigger flag, it will never be triggered (unless event is defined as Periodic)

Command#

  • Not Applicable

Command Parameters#

  • Not Applicable

Non Printable ASCII Chars - Token/Value Substitution#

token value token value token value token value token value
<NUL> 0 <SOH> 1 <STX> 2 <ETX> 3 <EOT> 4
<ENQ> 5 <ACK> 6 <BEL> 7 <BS> 8 <TAB> 9
<LF> 10 <VT> 11 <FF> 12 <CR> 13 <SO> 14
<SI> 15 <DLE> 16 <DC1> 17 <DC2> 18 <DC3> 19
<DC4> 20 <NAK> 21 <SYN> 22 <ETB> 23 <CAN> 24
<EM> 25 <SUB> 26 <ESC> 27 <FS> 28 <GS> 29
<RS> 30 <US> 31 <DEL> 127