HotLoop Transmitter API

Everything is in the HLTX namespace. The block is HLTX.FB_HLTX_Publisher.

Inputs

Input	Type	Default	Meaning
bEnable	BOOL	FALSE	TRUE opens the socket and starts publishing. FALSE closes it and returns the block to Disabled, which also clears a ConfigError
sDestination	STRING(15)	127.0.0.1	dotted IPv4 address: a unicast host, or a multicast group from 224.0.0.0 to 239.255.255.255
uiPort	UINT	4840	destination UDP port. 4840 is the one OPC UA registers
sLocalAddress	STRING(15)	empty	multicast only: the address of the interface to send from. Empty lets the OS choose
usiMulticastTTL	USINT	1	multicast time to live
uiPublisherId	UINT	1	PublisherId, sent as UInt16
uiWriterGroupId	UINT	1	WriterGroupId
uiDataSetWriterId	UINT	1	DataSetWriterId
tPublishingInterval	TIME	T#100MS	time between messages. Minimum T#1MS. The block can only send on a cycle, so the real rate is the interval rounded up to a whole number of cycles of the task that calls it
eEncoding	E_HLTX_Encoding	Variant	Variant or RawData. Change it while disabled
udiGroupVersion	UDINT	1	GroupVersion in the group header
udiConfigMajor, udiConfigMinor	UDINT	1, 0	DataSet ConfigurationVersion. Bump the major whenever the field list changes
bTimestamp	BOOL	TRUE	stamp every message with the PLC clock, in the NetworkMessage and the DataSetMessage (whole seconds, see WIRE-FORMAT.md). FALSE sends the 1.0.0 bytes, 17 bytes shorter
tRetry	TIME	T#2S	how long to wait before reopening the socket after ten sends in a row failed

Outputs

Output	Type	Meaning
eState	E_HLTX_State	Disabled, Running, Backoff (waiting to reopen the socket) or ConfigError (see eError; nothing is sent)
eError	E_HLTX_Error	None, NoFields, BadInterval, BadAddress, SocketCreate, SocketOption, TooBig, BadField
bActive	BOOL	TRUE while messages are going out
udiSent	UDINT	messages handed to the network
udiSendErrors	UDINT	sends the OS refused or cut short
udiSkipped	UDINT	publish slots missed because the task ran late
uiMessageSize	UINT	bytes in the last message
diLastSocketResult	UDINT	the last runtime error code from a socket call, 0 is fine
diLastClockResult	UDINT	the last result of reading the PLC clock for a timestamp, 0 is fine. When it is not 0 the message goes out unstamped
diLastClockResult	UDINT	the last result of reading the PLC clock for a timestamp, 0 is fine. When it is not 0 the message goes out unstamped
udiLastCallUs, udiMaxCallUs	UDINT	microseconds spent in the last call of the block, and the longest since enable or Clear()
udiMaxEncodeUs, udiMaxSendUs	UDINT	the longest time spent building one message, and in the send call itself, since enable or Clear()

Methods

Add fields once, before the first call, in the order a receiver should read them. Each returns TRUE when the field was accepted. Up to 128 fields.

Method	Adds
AddBool(pValue), AddSInt, AddUSInt, AddInt, AddUInt, AddDInt, AddUDInt, AddLInt, AddULInt, AddReal, AddLReal, AddTime	one scalar. pValue is ADR(variable)
AddString(pValue, uiMaxLen)	one STRING. uiMaxLen is the N in STRING(N)
AddArray(pFirst, eType, uiCount)	an array of uiCount elements of any type but STRING. pFirst is ADR(array[first])
AddField(pData, eType, uiCount, uiMaxLen)	the general form the others call
Clear()	forgets the field list and the maximum call time

The block keeps the addresses you give it, so after an online change that moves variables, call Clear() and add the fields again. WORD, DWORD and LWORD go in as UINT, UDINT and ULINT through the same-sized method.

Calling it

Call the instance once per cycle from one task. Do not call one instance from two tasks. Several publishers in one program are fine and each owns its own socket; give each its own writer group and dataset writer id.