VTI Instruments EX1401, User Manual

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EX1401 Instrument Drivers 89
Object Name String Value
Cold Junction
Temperature
Sensor Reading
Reference Junction The temperature of the CJC sensor, in the same
units as the channel data.
timestamp_sec The seconds portion of the timestamp of the
first TC sample that this CJC measurement was
used to compute.
timestamp_frac The fractional portion of the timestamp of the
first TC sample that this CJC measurement was
used to compute.
Over range Over-Range True when any overload status bit is set.
Trigger time Trigger Timestamp
Seconds The trigger timestamp in seconds
Trigger Timestamp
Fraction The fraction portion of the trigger timestamp.
Dropped trigger timestamp_sec The timestamp of when the trigger would have
occurred.
timestamp_frac The fraction portion.
Trigger Dropped The channel name of the lost trigger.
T
ABLE
5-4: A
DDITIONAL
D
ATA
JSON N
AMES AND
V
ALUES
M
EASUREMENT
P
ROCESS
M
EASUREMENT
S
ETUP
When the driver session is initialized by the Initialize method, the driver session is reset, or after the
previous measurement is finished, the instrument is in the Idle state. While in the Idle state, the user
prepares for the next data acquisition by configuring the setup parameters. For more information,
please refer to IVILXISync standard API documentation
Sync and Coordination
The Sync interface controls how the EX1401 synchronizes its ADCs and its timestamp counter.
When a sync event occurs, all ADCs in the system are synchronized to each-other, and all data
timestamp counters are reset and, if using the System Timestamp Source, synchronized to the IEEE
1588 clock. If the
Sync.CoordinationLine property is set to “LAN”, all instruments in the driver
session will use LXI Lan Event messages to coordinate their trigger state machines, ensuring that
all arm and trigger events are shared between all instruments in the system.
Start, Arm, and Trigger
Properties in the Start , Arm , and Trigger interfaces configure the data acquisition gating condition
and timing. Start determines when the data acquisition starts and when the instrument is ready for
the next acquisition. All hardware configuration and filters settling should be completed before the
Start event in order to ensure valid data is acquired.
Sampling Parameters
The sampling parameters are specified by properties in Sampling interface. Sampling in the
Measurement interface configures parameters common to the entire system. Optionally, the user can
configure the parameters of individual input channels using the Channels interface (with some
restrictions).