Rockwell Automation Allen-Bradley ControlLogix 1756-MVI Programming Reference Manual page 49

MVIbp_SetUserLED
Syntax:
int MVIbp_SetUserLED(MVIHANDLE handle, int lednum, int
ledstate);
Parameters:
handle handle returned by previous call to MVIbp_Open
lednum specifies which of the user LED indicators is being
addressed
ledstate turns the LED on or off
Description:
MVIbp_SetUserLED allows an application to turn the user LED
indicators on and off. handle must be a valid handle returned from
MVIbp_Open.
lednum must be set to MVI_LED_USER1 or MVI_LED_USER2 to select
User LED 1 or User LED 2, respectively.
ledstate must be set to MVI_LED_STATE_ON or MVI_LED_STATE_OFF
to turn the indicator On or Off, respectively.
Return Value:
MVI_SUCCESS
MVI_ERR_NOACCESS
MVI_ERR_BADPARAM
Example:
MVIHANDLE Handle;
/* Turn User LED 1 on and User LED 2 off */
MVIbp_SetUserLED(Handle, MVI_LED_USER1, MVI_LED_STATE_ON);
MVIbp_SetUserLED(Handle, MVI_LED_USER2, MVI_LED_STATE_OFF);
the input scan has occurred
handle does not have access
lednum or ledstate is invalid
Publication 1756-RM004B-EN-P - October 2000
MVI Backplane API 3-27