VTI Instruments EX1000A, User Manual

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EX10xxA Triggering 63
NOTE Self calibration is not applicable for RX1032 since during factory calibration process each
instrument will be calibrated in precise manner and calibrated data gets stored in the instrument
memory. The instrument has to be sent to factory to perform subsequent calibration after the initial
calibration date is expired.
Refer below section for Dynamic Calibration in RX1032
D
YNAMIC
C
ALIBRATION IN
RX1032
The dynamic calibration should be conducted to calibrate the measurement drift due to the
temperature change. For every measurement scan, the values are adjusted based on the system
internal temperature.

The initial calculated Voltage and Temperature coefficients are stored into the RX1032
system.

At every measurement the measured values are calibrated dynamically using the stored
coefficients.

Based on the present temperature of the system, the values are calibrated and reported.
O
PEN
T
RANSDUCER
D
ETECTION
/ L
IMITS
The EX10xxA provides two unique sets of programmable limits that are used for open transducer
detection as well as general purpose input channel monitoring. These limits, termed limit set 0 and
limit set 1, are programmable on a per channel basis. Limit conditions are evaluated with each
completed scan and are updated with a maximum latency of 25 ms.
Each limit set has an upper and lower limit value, and limit evaluations can be done against either
or both values. The output of limit evaluations is presented in three forms. The operation of the front
panel LEDs is tied to the upper and lower limit values of limit set 0. The operation of the digital I/O
port can be optionally linked to any combination of the upper and lower limit values of either or
both limit sets. Finally, this information is accessible through the instrument driver.
Because of its linkage to the front panel LEDs and the typical use of these LEDs as open transducer
detection, limit set 0 has a unique operating feature not present in limit set 1. By default, the values
in limit set 0 are set automatically, based on the EU conversion and units selection for each channel.
Specifically, the upper and lower limit values are set to the upper and lower values of the EX10xxA
measurement range, as specified in Table 3-2. If desired, this automatic operation can be disabled,
allowing the manual setting of the limit values. In manual operating mode, the limit values remain
constant through EU conversion and unit changes. Limit set 1 operates in manual mode only.
As previously mentioned, limit evaluations can be linked to the operation of the digital I/O port.
This is called a DIO Limit Event. For more information, see
Digital I/O and DIO Limit Events .
The clearing of limit conditions is slightly different for each presentation mechanism. The front
panel LEDs always operate in a latch configuration, meaning that a channel’s LED remains
illuminated even if subsequent channel readings within an acquisition sequence are not out of limit.
This behavior is critical to identifying an open thermocouple that is intermittent in its failure.
Clearing is done at the beginning of a new acquisition. DIO Limit Events can be programmed to
operate in latch or non-latch mode. In either case, they are also cleared at the beginning of a new
acquisition. Finally, the instrument driver provides information on the accumulated limit status and
is cleared at the beginning of a new acquisition. The default values for each limit set are their
maximum values.
D
IGITAL
I/O
AND
DIO L
IMIT
E
VENTS
The EX10xxA/EX10xxA-51C/EX1044 features an 8-channel digital I/O port on the rear panel of
the instrument. This port can be used as an arm/trigger source, for presentation of limit evaluation