Allen-Bradley Compact 1769-IR6, Руководство пользователя

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Publication 1769-UM005A-EN-P
4-10 Module Data, Status, and Channel Configuration
Linear Relationship Between Temperature and Proportional Counts
The value +32767 corresponds to the highest value for the device. For
example, if a 100
Ω
platinum 385 RTD is selected, the lowest temperature
of -200
°°°°
C corresponds to -32768 counts. The highest temperature of 850
°°°°
C
corresponds to +32767 counts. See Determining Effective Resolution and
Range on page 4-19.
Scaling Examples
+ 32,767
-32,768
850 ˚C
±200 ˚C
Counts
°C
EXAMPLE
Scaled-for-PID to Engineering Units x1
•
input type = 200
Ω
Platinum RTD
• α
= 0.00385°C
•
range = -200 to +850°C S
LOW
= -200°C S
HIGH
= +850°C
•
channel data = 3421(scaled-for-PID)
Engineering Units Equivalent = S
LOW
+ [S
HIGH
- S
LOW
) x (channel data/16383)]
Engineering Units Equivalent = -200°C + [(+850°C -(-200°C)) x (3421/16383)] =
19.25°C