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5 Advanced Operations
Using the PV Input Shift
After shifting
1000 °C
970 °C
500°C is shifted to 550°C.
550 °C
500 °C
(1) Find the two points to shift and determine the PVs after the shifts are applied.
Example: Shift 500°C (temperature before shifting) to 550°C (temperature after shifting).
Example: Shift 1,000°C (temperature before shifting) to 970°C (temperature after shifting).
(2) Find the process value slope coefficient from the above results.
(970 − 550) / (1,000 − 500) = 0.840
* Do not yet set the Process Value Slope Coefficient parameter in the Digital Controller.
(3) Adjust the PV display on the Digital Controller to the point to be shifted.
Example: Adjust the PV to 500°C.
(4) Set the Process Value Slope Coefficient parameter to the value that you found in
step 2.
Example: Set the Process Value Slope Coefficient parameter to 0.840.
(5) Read off the PV after the setting is changed.
Example: The PV will be displayed as 420°C.
(6) Find the difference between the anticipated PV (i.e., the PV after shifting) and the PV
that you read off in step 5.
Example: 550°C − 420°C = 130°C
(7) Set the Process Value Input Shift parameter to the value that you found in step 6.
Example: Set the Process Value Input Shift parameter to 130°C.
5 - 26
200 °C
500 °C
1000 °C
1,000°C is shifted to 970°C.
Before shifting
1300 °C
E5@D Digital Temperature Controllers User's Manual (H224)
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