Thunder Scientific 2500 series, Руководство по эксплуатации и обслуживанию

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4-2
Calibration of all transducers is to be performed "in the system, as a system". There are no
provisions for, nor do we recommend, calibration of any of the transducers (temperature,
pressure, or flow) while electrically disconnected from the generator. Since all calibration is
performed mathematically by the computer, there are no manual adjustments.
Calibration is performed on all of the transducers by solving for the coefficients A, B, and C
of the formula:
Y=A+Bx+Cx 2
where x is the raw count (or uncalibrated output of the A/D
converter) while measuring a transducer, and
Y is the desired value (the standard or reference
transducer's reading) for the transducer being calibrated.
The three coefficients A, B, and C are found by applying three separate, distinct, and stable
references to each transducer, then solving the mathematical system of three equations with
three unknowns. Since all of these calculations are performed automatically by the 2500's
embedded computer, the operator need only be concerned with providing three known stable
references required for the calibration of each transducer.
4.2.1 A/D Board (STD-A/D)
Equipment Required: (None)
All calibration errors appearing in the A/D board will be accounted for automatically during
calibration of the temperature, pressure, and flow transducers. The board is also equipped
with built in auto-zero and auto-span circuitry which automatically and continually accounts
for short and long term drift in measurement accuracy. No user calibration is required. A
board suspected of extreme inaccuracies or malfunctions should be sent to the factory for
repair.
4.2.2 Temperature Calibration
The systems EDIT/CAL mode may be used in conjunction with a precision temperature bath
for temperature probe calibrations. Any combination of one or more temperature probes may
be calibrated at any one time, leaving calibration of the remaining probes unaltered.
By using the temperature bath to generate three known temperatures, all coefficients (ZERO,
SPAN, LINEARITY) can be calculated automatically by the embedded computer and used to
update the system calibration. A new calibration report may also be printed at the conclusion
of the calibration sequence.
Equipment Required:
1. Temperature Bath (per section 4.2).
2. Standard or Reference thermometer (per section 4.2)
3. 7/16" open end wrench
4. Needle nose pliers
5. #10 Torx driver