Rockwell Automation 1746-NR8 SLC 500 RTD/Resistance Input Module User Manual - Manual (Page 59)

Publication 1746-UM003A-EN-P
Channel Configuration, Data, and Status 4-11
Scaling Examples
The following examples are using the default scaling ranges:
Scaled-for-PID to Engineering Units
Equation:
Assume that the input type is an RTD, Platinum (200
Ω
, a = 0.00385°C,
range = -200°C to +850°C), scaled-for-PID display type. Channel data = 3421.
Want to calculate °C equivalent.
From Channel Data Word Format, S
LOW
= -200°C and S
HIGH
= 850°C.
Solution: Solution: Solution: Solution:
Engineering Units to Scaled-for-PID
Equation:
Assume that the input type is an RTD, Platinum (200
Ω
, a = 0.00385°C,
range = -200°C to +850°C), scaled-for-PID display type. Desired channel
temperature = 344°C.
Want to calculate Scaled-for-PID equivalent.
From Channel Data Word Format, S
LOW
= -200°C and SHIGH = 850°C.
Solution:
Engr Units Equivalent SLOW SHIGH - SLOW ( )
Scaled-for-PID value displayed
16383
-------------------------------------------------------------------------------
 
 
× + =
Engr Units Equivalent 200°C 850°C - (-200°C)
( )
3421
16383
---------------
 
 
×
19.25°C = + =
Scaled-for-PID Equivalent 16383
Engr Units desired - SLOW
( )
SHIGH - SLOW
( )
-------------------------------------------------------------------------- ×
=
Scaled-for-PID Equivalent 16383
344°C -200°C
( )
+
850°C- (-200°C)
----------------------------------------------- Ч
8488 = =