User manual

Chapter 3 Software Overview
NI-DAQ User Manual for PC Compatibles 3-60 ni.com
Digital Change Notification Functions
The Digital Change Notification functions provide messaging for lines
and ports on the 652X devices. For other boards such as the DIO-24, the
Config_DAQ_Event_Message
function handles event messaging.
DIG_Change_Message_Config
Configures 652X devices to detect rising or
falling edges on input lines and to notify
you by generating a message.
DIG_Change_Message_Control
Controls the change notification operation
of the digital input lines on 652X devices.
Digital Filtering Function
The Digital Filtering function provides signal conditioning to filter the
inputs of 652X devices.
DIG_Filter_Config
Configures filtering for the input lines on
652X devices.
Digital Change Notification Applications with
652X Devices
Digital change notification applications automatically detect changes on
input lines and notify you or your software by message. These applications
may use digital filtering to eliminate signals that may trigger unwanted
change notification. Digital filtering can be used alone to condition and
debounce input data.
Figure 3-18 illustrates the series of calls needed for change notification on
the input data. Figure 3-19 illustrates the series of calls needed for filtering
the input data without change notification. Only 652X devices can execute
change notification and filtering applications using these functions.