Emerson Rosemount 644h, Справочное руководство

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Reference Manual
00809-0100-4728, Rev HA
December 2002
Models 644H and 644R
A-4
CE Mark
The Models 644H and 644R meet all requirements listed under IEC 61326:
Amendment 1, 1998.
Power Supply Effect
Less than ±0.005% of span per volt
Vibration Effect
The Model 644H and Model 644R are tested to the following specifications
with no effect on performance:
Stability
RTDs and thermocouples have a stability of ±0.1% of output reading or 0.1 °C
(whichever is greater) for 24 months
Self Calibration
The analog-to-digital measurement circuitry automatically self-calibrates for
each temperature update by comparing the dynamic measurement
to extremely stable and accurate internal reference elements.
Sensor Connections
Frequency Vibration
10 to 60 Hz 0.21 mm displacement
60 to 500 Hz 3 g peak acceleration
Model 644
244EH
Sensor Connections Diagram
* Emerson Process Management provides 4-wire sensors for all single element RTDs. You can use these
RTDs in 3-wire configurations by leaving the unneeded leads disconnected and insulated
with electrical tape.
2-wire
RTD and
3-wire RTD
and
4-wire RTD
and
T/C
and mV
*
1 2 3 4 1 2 3 4
1 2 3 4
1 2 3 4
644
-000
B01A
Rosemount Conformance to Specifications
A Rosemount product not only meets its published specifications, but most likely exceeds
them. Advanced manufacturing techniques and the use of Statistical Process Control
provide specification conformance to at least ± 3
(1)
. Our commitment to continual
improvement ensures that product design, reliability, and performance will improve
annually.
For example, the Reference Accuracy distribution for the Model 644 is shown to the right.
Our Specification Limits are ± 0.15 °C, but, as the shaded area shows, approximately 68%
of the units perform three times better than the limits. Therefore, it is very likely that you will
receive a device that performs much better than our published specifications.
Conversely, a vendor who “grades” product without using Process Control, or who is not
committed to ± 3
performance, will ship a higher percentage of units that are barely within
advertised specification limits.
Accuracy distribution shown is for the Model
644, Pt 100 RTD sensor, Range 0 to 100 °C
(1) Sigma (
σ
) is a statistical symbol to designate the standard deviation from the mean value of a normal distribution.
Lower
Specification
Limit
Upper
Specification
Limit
Typical Accuracy
3144-
GRAPH
–3 σ –2 σ –1 σ 1 σ 2 σ 3 σ