User manual

Chapter 3 Software Overview
© National Instruments Corporation 3-99 NI-DAQ User Manual for PC Compatibles
Figure 3-39. Example Clock in a Measurement System
Sample Use Cases
The following cases are examples of applications that can use clocks.
UseCase#1
Theuserrecordsthetimeofn events with software timing precision.
A user wants to record the time of an external event—for example,
when a key is pressed on a keyboard, when a data packet is received by
a CAN controller, or when a temperature is read from an AI channel.
The software program flow is as follows:
1. Initialize the clock for this application.
• Specify the synchronization signal type (none).
• Specify the initial DHMS value (the default value of DHMS is
undefined).
2. Read the clock value (days, hours, minutes, seconds) when the external
event happens to determine the time of the event.
3. At the end of the operation, free up any hardware and software
resources. After powering up, the clock will run until the power to
the TIO ASIC is turned off.
Controller
6602
E Series
1407
Trigger 1
Trigger 2
GPS
Rcvr
RS232
PPS