Owner`s manual

M SERIES DAC
BASE UNIT AND MODULE OPERATION
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The V77 ADM-1 generates digital data messages by taking samples of the analog
input voltage(s) at a specified sampling rate. The V77 ADM-1 computes an average
value of these samples and presents this average to the host device in the form of a
data message. The number of samples taken per data message is determined by the
Number of Samples to Average. The V77 ADM-1 will sample analog inputs in one
of three ways: Command (via command only), Immediate, and Schedule. A host
module may request a data message on command using any of these Sampling
Methods. Immediate Sampling Method provides continuous or repetitive interval
sampling. Schedule Sampling Method is basically the same as Immediate except
sampling begins at a specified Sample Start Time.
If a Sample Interval is used, the V77 ADM-1 will sample the input(s) in repetitive
intervals. The Sample Interval is the time between the start of sample periods. A
sample period is the time the V77 ADM-1 actually samples between each Sample
Interval. The sample period is computed by dividing the Sampling Rate by the
Number of Samples to Average. For example, suppose every 10 minutes you desire
to sample at a 60 S/sec rate and average 720 samples. The V77 ADM-1 acquires 720
samples in 12 seconds (720/60), buffers the data, then waits 9 minutes and 48 seconds
before taking another 720 samples. If the Reporting Period is set to 10 minutes, the
data collected during the most recent Sample Interval is reported.
Figure 3: Sample Interval
DATA MESSAGE PRESENTATION
Data message presentation varies slightly in format depending on module
configuration. Entries such as, time tag, data format, number of active channels, etc.
all change how data messages appear to a host-controller. However, all data
messages are presented in the same basic order of fields as follows:
UU:MM,CC HHH or DDDD or VV MM/DD/YY HH:MM:SS