Omron E5CN User Manual page 105

Shifting Input Values
Method for a 2-point
Shift
1,2,3...
Controller readout after
shifting (e.g., 110°C)
Controller readout before
shifting (e.g., 105°C)
Controller readout before
shifting (e.g., 40°C)
Controller readout after
shifting (e.g., 25°C)
Example of a 2-point
Temperature Input
Shift
80
Use a 2-point input shift if you want to increase the accuracy of the readout
values across the range of the Sensor.
1. Shift the Controller readout at two points, near room temperature and near
the value at which the temperature of the control target is to be controlled.
For this reason, check the thermometer temperature (B) and Controller
readout (A) with the thermometer temperature near room temperature and
near the set point.
2. Use the following formulas with the readouts checked above and the de-
sired temperature values to calculate the input shift values for the upper-
limit and lower-limit temperatures of the measurement range and set the
upper-limit and lower-limit temperature input shift values. The shift is illus-
trated in Figure 3.
Controller readout (A)
Set temperature upper
limit YH (e.g., 260°C)
0
X1 Room temper-
ature (e.g., 25°C)
Lower-limit
Set temperature lower
temperature input
limit YL (e.g., 0°C)
shift value insl
Figure 3 Illustration of 2-Point Shift
a. Lower-limit temperature input shift value
YL − Y1
insl =
Y2 − Y1
b. Upper-limit temperature input shift value
YH − Y1
insh =
Y2 − Y1
3. After setting the calculated values to insl and insh, check the Controller
readout (A) and thermometer temperature (B).
4. Here, offsets are set at two points, near room temperature and near the set
point. To improve accuracy within the measurement temperature range,
another point in the measurement temperature range other than the set
point should be set instead of room temperature.
In this example, we use the ES1B K 140 to 260 ° C specification. In equations 1
and 2, the set temperature lower limit YL is 0 ° C and the set temperature upper
limit YH is 260 ° C. Check the temperature of the control target.
The temperature input offset values can be calculated as shown below when
the Controller readout Y1 is 40 ° C for a room temperature X1 of 25 ° C and
when the Controller readout Y2 is 105 ° C for a set point temperature X2 of
110 ° C.
After shifting
Upper-limit temperature
input shift value insh
Before shifting
Control target temperature (B)
X2 Near set point (e.g., 110°C)
× {(X2 − Y2) − (X1 − Y1)} + (X1 − Y1)
× {(X2 − Y2) − (X1 − Y1)} + (X1 − Y1)
Section 4-1