Configuration - Rockwell Automation Allen-Bradley ControlLogix 1756-MVI Programming Reference Manual

3-8 MVI Backplane API
Publication 1756-RM004B-EN-P - October 2000

Configuration

MVIbp_GetIOConfig
Syntax:
int MVIbp_GetIOConfig(MVIHANDLE handle, MVIBPIOCONFIG
*ioconfig);
Parameters:
handle handle returned by previous call to MVIbp_Open
ioconfig pointer to MVIBPIOCONFIG structure to receive
configuration information
Description:
This function is used to obtain the I/O configuration of the MVI
module. handle must be a valid handle returned from MVIbp_Open.
The MVIBPIOCONFIG structure is defined as shown below:
typedef struct tagMVIBPIOCONFIG
{
WORD TotalInputSize;
WORD TotalOutputSize;
WORD DirectInputSize;
WORD DirectOutputSize; // Output words available for direct access
WORD MsgRcvBufSize;
WORD MsgSndBufSize;
} MVIBPIOCONFIG;
The sizes in words of the module's input and output images are
returned in the MVIBPIOCONFIG structure pointed to by ioconfig. The
TotalInputSize and TotalOutputSize members are set equal to the size of
the entire input or output image, respectively. The DirectInputSize and
DirectOutputSize members are set equal to the number of words of the
respective image that is available for direct access via the
MVIbp_WriteInputImage or MVIbpReadOutputImage functions. The
MsgRcvBufSize and MsgSndBufSize members indicate the maximum
size in words for received or sent messages, respectively.
The IO data connection is configured by the processor and cannot by
altered by the module. Therefore, the direct and total sizes are always
equal and are set to the sizes configured by the module profile. The
message sizes are set to the maximum message size.
Return Value:
MVI_SUCCESS
MVI_ERR_NOACCESS
// Size of entire input image in words
// Size of entire output image in words
// Input words available for direct access
// Max size in words for received messages
// Max size in words for sent messages
no errors were encountered
handle does not have access