DAQ Pacer Clock - neoVI
Main

Applies to
neoVI Blue

Overview

The neoVI device can generate a clock (figure 1) on the MISC2 pin that can be used to correlate data collected with the neoVI device with other data acquisition equipment that accepts an external clock. The clock rate is programmable between 1.25 Khz and 2.5 Mhz (See table 1 for frequencies).

The neoVI devices timestamps the exact start time of the pulses. This start timestamp provides a marker to compare data from the DAQ board and the neoVI.

How to use it

The following list of steps shows how to use this feature: 

Step 1 : Wire the MISC 2 signal to the DAQ card external clock input
Step 2 : Setup the MISC 2 Signal as a digital output in neoVI explorer
Step 3 : Start Monitoring the network
Step 4 : Start the DAQ Card Data Acquisition for an external clock with the desired number of samples
Step 5 : Send the Start DAQ neoVI Device Virtual Network Command to start the clock. neoVI will send a neoVI Device Network message time-stamped when the DAQ Clock was started.
Step 6 : Record network messages from the neoVI until the DAQ card has acquired the proper number of samples
Step 7 : After the DAQ Card completes its scan, assemble the DAQ card data and neoVI message buffer in to one buffer using the start timestamp. Analyze, display or store your results.
Step 8 : Send the Stop DAQ neoVI Device Virtual Network Command to stop the DAQ Clock.

Figure 1 - neoVI generates a pulse at a frequency which is time correlated with the neoVI timestamp.

Table 1 - Sampling Frequency for the DAQ Pacer

Last Update: Thursday, July 09, 2009