Allen-Bradley Compact 1769-IR6, Руководство пользователя

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Publication 1769-UM005A-EN-P
Module Data, Status, and Channel Configuration 4-11
EXAMPLE
Engineering Units x1 to Scaled-for-PID
•
input type = 200
Ω
Platinum RTD
• α
= 0.00385°C
•
range = -200 to +850°C S
LOW
= -200°C S
HIGH
= +850°C
•
desired channel temperature = 344°C (engineering units)
Scaled-for-PID Equivalent = 16383 x [(desired ch. temp. - S
LOW
)/(S
HIGH
- S
LOW
)]
Scaled-for-PID Equivalent = 16383 x [(344°C - (-200°C))/(850°C - (-200°C))] = 8488
EXAMPLE
Proportional Counts to Engineering Units x1
•
input type = 1000
Ω
potentiometer
•
range = 0 to 1000
Ω
S
LOW
= 0
Ω
S
HIGH
= 1000
Ω
•
channel data = 21567 (proportional counts)
Engineering Units Equivalent = S
LOW
+ {(S
HIGH
- S
LOW
) x [(ch. data + 32768)/
65536]}
Engineering Units Equivalent = 0 + {(1000 - 0) x [(21567 + 32768)/65536]} = 829
Ω
EXAMPLE
Engineering Units x1 to Proportional Counts
•
input type = 3000
Ω
potentiometer
•
range = 0 to 3000
Ω
S
LOW
= 0
Ω
S
HIGH
= 3000
Ω
•
desired channel resistance = 1809
Ω
(engineering units x 1)
Prop. Counts Equivalent = {65536 x [(ch. resistance - S
LOW
)/(S
HIGH
- S
LOW
)]} -
32768
Proportional Counts Equivalent = {65536 x [(1809
Ω
-
0)/(3000 − 0)]} − 32768
=
6750
AB PLCs