Chapter 6
NI-FBUS Function Reference
©
National Instruments Corporation
6-65
NI-FBUS Hardware and Software User Manual
If you have multiple threads waiting to receive the same trend, the NI-FBUS Communications
Manager sends a copy of the trend to all the waiting threads. You can abort a pending
nifWaitTrend
call by closing the descriptor on which the call was made.
The
trend
type can be
TREND_FLOAT
,
TREND_DISCRETE
, or
TREND_BITSTRING
.
The sample type can be
SAMPLE_INSTANT
or
SAMPLE_AVERAGE
.
nifTrendData_t
is defined as follows:
typedef struct nifTrendData_t {
uint8 trendType;
char deviceTag[TA 1];
char blockTag[TA 1];
char paramName[TA 1];
uint8 sampleType;
uint32 sampleInterval;
nifTime_t lastUpdate;
uint8 status[16];
union {
float f[16];
uint8 d[16];
uint8 bs[32];
} trendData;
} nifTrendData_t;
Return Values
E_OK
The call was successful.
E_INVALID_DESCRIPTOR
The descriptor you gave is not valid.
E_SERVER_CONNECTION_LOST
The session established with the NI-FBUS Communications
Manager for this descriptor has been closed or lost.
