National Instruments FOUNDATION NI-FBUS Hardware And Software User Manual page 102

Chapter 6 NI-FBUS Function Reference
Description
nifGetObjectType
block parameters, MIB objects, or communication parameters from devices.
• If is the descriptor of a link, then
ud
format.
• If is a session descriptor, then all links are searched for the given
ud
BLOCKTAG.PARAM_NAME
found on the bus. Index access is not allowed for session descriptors.
• If is the descriptor of a general function block application VFD, and you use the
ud
NIFB_INDEX
• If is the descriptor of a function block,
ud
• If is the descriptor of a function block, and you use the
ud
NIFB_INDEX_SUBINDEX
parameter within the block. Relative indices start at one for the first parameter.
Index zero retrieves the OD type of the block itself.
• In all cases, you can expand
named element of a named structure.
Refer to Table 6-5 for an explanation of how to use macros to specify the parameter.
The
nifObjTypeList_t
typedef struct {
uint8 objectCode;
uint16 numElems;
char blockTag[TAG_SIZE + 1];
nifObjElem_t *allElems;
} nifObjTypeList_t;
The
nifObjElem_t
typedef struct {
uint16 objTypeIndex;
uint16 objSize;
} nifObjElem_t;
The
objectCode
FMS Specifications section of the Fieldbus Foundation Specifications document and is listed
in Table 6-3, for your convenience.
NI-FBUS Hardware and Software User Manual
is used to read the Object Dictionary type values of objects such as
. The call fails if identical
macro, the index specified is the index of the object in the VFD.
macro, the index specified is the relative index of the
PARAM_NAME
data structure is defined as follows:
data type is defined as follows:
returned in the data structure
6-40
must be in
objName BLOCKTAG.PARAM_NAME
BLOCKTAG.PARAM_NAME
must be in
name
to
STRUCT.ELEMENT
nifObjTypeList_t
tags are
format.
PARAM_NAME
or
NIFB_INDEX
format to represent a
is as specified in the
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