Rockwell Automation 900-TC32 Digital Temperature Controllers, Series B - Manual (Page 137)

4-1 Publication 900-UM007D-EN-E - January 2011
Chapter
4
Parameter Adjustments & Application
Considerations
Shifting Input Values Overview
The Input Shift parameter allows you to configure the controller to
compensate for possible deviation of the measured temperature (PV) to the
actual temperature at the source (control target). The controller supports two
types of input shifts, 1-point and 2-point. The input shift type is automatically
matched to the sensor currently selected by the Input Type parameter
(configured value — See Table 3.C, — List of Global Temperature (GT) Input
Types
). There is no shift for analog inputs. Use scaling for fine adjustments.
1-Point (Uniform) Shift
Overview
Figure 4.1
With 1-point shift operation, the Temperature Input Shift parameter
(Adjustment function group) is applied to the entire temperature input range
in a uniform or consistent manner. In other words, the adjusted value is
applied equally to each input/sensor value read by the controller and displayed
as such. For example, if the input shift value is configured to 1.2
°C, the
process value is treated by the controller as 201.2
°C after input shift is applied
when the measured process value is 200
°C (refer to Figure 4.2).
Figure 4.2 — One-Point Shift
Input
Temperature
Upper-limit
value
After shift
Input shift value
Before
shift
0
100
Lower-limit
value