Omron EJ1 User Manual page 80

Setting Input Specifications
Two-point Shift
Method
1,2,3...
Controller readout after shifting (e.g., 550 C)
Controller readout before shifting (e.g., 500 C)
Controller readout before shifting (e.g., 40 C)
Controller readout after shifting (e.g., 25 C)
1. Shift the controller readout at two reference temperatures, near room tem-
perature and near the value at which the temperature of the control target
is to be controlled. Bring the temperature of the control target close to room
temperature and close to the set point, and check control target tempera-
ture (B) and controller readout (A).
2. Check the temperature of the control target near room temperature (B) and
the controller readout (A), and calculate the temperature difference as
shown below.
Object temperature (B)
Set the temperature difference as Input Shift 1 and set the controller read-
out (A) as Input Value 1 for Input Correction.
3. Check the temperature of the control target near set-point temperature (B)
and the controller readout (A), and calculate the temperature difference as
shown below.
Object temperature (B)
Set the temperature difference as Input Shift 2 and set the controller read-
out (A) as Input Value 2 for Input Correction.
4. After you have set the calculated values, check controller readout (A) and
control target temperature (B).
5. In this case, the two-point shift was performed near room temperature and
the set-point temperature, but if you want to improve accuracy near the set
point, perform the two-point shift at points above and below the set-point
temperature. An example shift is shown in the following diagram.
Input value 2 for Input Correction
Input value 1 for Input Correction
■ Two-point Shift Example
In this example, the input type is set to K (5): 200°C to 1,300°C.
Check the temperature of the control target.
When room temperature (B) = 25°C,
the Controller readout (A) = 40°C.
When the temperature near the set point (B) = 550°C,
the Controller readout (A) = 500°C.
In this case, the input shift parameters are calculated as follows:
Input Value 1 for Input Correction = Controller readout (A) = 40°C
Input Shift 1 = Object temperature (B) - Controller readout (A) =
25°C 40°C = 15.00°C
Controller readout (A)
Controller readout (A)
Controller readout (A)
After shifting
Input Shift 1
0
Room temperature
(e.g., 25 C)
Section 4-1
Input Shift 2
Before shifting
Control target temperature (B)
Temperature near set point
(e.g., 550 C)
55