Ivi_RestrictAttrToChannels
Usage
ViStatus Ivi_RestrictAttrToChannels(ViSession vi, ViAttr attributeID, ViChar ChannelStringsList[ ]);
Purpose
This function restricts an attribute to specific channels, thereby excluding you from using the attribute on other channels. You can call this function only on attributes for which you have enabled the IVI_VAL_MULTI_CHANNEL flag.
When you initially add an attribute, it applies to all channels. If you want it to apply to only a subset, call this function. This function can only be called once after an attribute has been created.
Example:
Ivi_BuildChannelTable (vi, "1,2,3,4", VI_FALSE, VI_NULL);Ivi_RestrictAttrToChannels (vi, PREFIX_ATTR_RANGE, "1,2");
As a result of these function calls, PREFIX_ATTR_RANGE is valid only for channels "1" and "2".
Parameters
| Name | Type | Description |
|---|---|---|
| vi | ViSession |
The ViSession handle that you obtain from Ivi_SpecificDriverNew. The handle identifies a particular IVI session. |
| attributeID | ViAttr |
Pass the ID of an attribute for this parameter. The include file for a specific instrument driver defines constant names for all of the user-accessible attributes that apply to the driver. This includes attributes that the IVI engine defines, attributes that the instrument class defines, and attributes that are specific to the particular instrument. Each defined constant name begins with PREFIX_ATTR_, where PREFIX is the specific instrument prefix. For each IVI engine attribute, the specific driver include file uses the same constant name that appears in ivi.h, except that the specific instrument prefix replaces the IVI prefix. For example, ivi.h defines IVI_ATTR_CACHE, and the Fluke 45 include file, fl45.h, defines the following constant name: #define FL45_ATTR_CACHE IVI_ATTR_CACHE For each instrument class attribute, the specific driver include file uses the same constant name that appears in the instrument class include file, except that the specific instrument prefix replaces the class prefix. For example, the DMM class include file, ividmm.h, defines IVIDMM_ATTR_RANGE, and fl45.h defines the following constant name: #define FL45_ATTR_RANGE IVIDMM_ATTR_RANGE For each specific instrument attribute, the specific driver include file defines a constant name and assigns a value that is an offset from IVI_SPECIFIC_PUBLIC_ATTR_BASE. For example, fl45.h defines the following constant name: #define FL45_ATTR_HOLD_THRESHOLD \ (IVI_SPECIFIC_PUBLIC_ATTR_BASE + 3L) For each attribute that is private to an instrument driver, the instrument driver source file defines a constant name and assigns a value that is an offset from IVI_SPECIFIC_PRIVATE_ATTR_BASE. For example, hp34401a.c defines the following constant name: #define HP34401A_ATTR_TRIGGER_TYPE \ (IVI_SPECIFIC_PRIVATE_ATTR_BASE + 1L) |
| ChannelStringsList | ViChar[ ] |
Pass a list of the channel strings to which you want to restrict the attribute you specify. You must separate channel strings with commas. You can include spaces after the commas. For example, if you call Ivi_BuildChannelTable with the channel string "1,2,3,4", then pass "1,2" for this parameter to restrict the attribute you specify to channels "1" and "2". |
Return Value
Contains the status code that the function call returns. IVI engine functions can return error and warning values from several sets of status codes. Some status codes are unique to the IVI engine. Other status codes are the same codes that VISA Library functions return. Still others are error or warning values that functions in specific instrument drivers return. Each set of status codes has its own numeric range.
Regardless of the source of the status code, 0 always indicates success, a positive value indicates a warning, and a negative value indicates an error.