National Instruments FOUNDATION NI-FBUS Hardware And Software User Manual page 126

Chapter 6 NI-FBUS Function Reference
nifWaitTrend
Purpose
Waits for a trend from a specific device or from any device.
Format
nifError_t
Input
ud
Output
trend
Context
Block, VFD, physical device, link, session.
Description
represents a descriptor of a session, link, physical device, VFD, or block. If
ud
descriptor, then the NI-FBUS Communications Manager waits for a trend from any block in
the Virtual Field Device. If
a trend from the block
is received from any device connected to that link. If the descriptor is a session descriptor,
nifWaitTrend
nifWaitTrend
receives a trend. Your application can have a dedicated thread which does
only.
When a trend comes in, the
The form of
trend->trendData
three trend types:
type is
TREND_FLOAT
numbers. If the trend type is
array of 1-byte integers. If the trend type is
a 16-element array of 2-byte bit strings, which is equivalent to a 32-element array of 1-byte
integers.
deviceTag
the trend;
paramName
NI-FBUS Hardware and Software User Manual
nifWaitTrend(
nifDesc_t ud,
nifTrendData_t *trend)
The descriptor of the session, physical device, VFD, block,
or link that the trend comes from.
The information about the specific trend.
is a block, the NI-FBUS Communications Manager waits for
ud
identifies. If
ud
waits on any trend from any attached link.
waits indefinitely until the NI-FBUS Communications Manager interface
parameter is filled in with the information about the trend.
trend
depends on the value
,
TREND_FLOAT TREND_DISCRETE
, the
trend->trendData
TREND_DISCRETE
and are the device and block tags of the parameter that has
blockTag
is the name of the parameter.
represents a link, the call completes when a trend
ud
of trend->trendType
, and
TREND_BITSTRING
is a 16-element array of floating point
, the
trend->trendData
TREND_BITSTRING
6-64
is a VFD
ud
nifWaitTrend
. There are
. If the trend
is a 16-element
, the
trend->trendData
is
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