Chapter 6 Temperature Measurement Module AH04TC/AH08TC 
6-9 
 
b. Interrupt service routine
 
The procedure below explains how to trigger an interrupt service routine in a CPU module. 
 
 
  The interrupt service routines are I40~I251. 
7. PID control
 
a. KP/KI/KD 
Proportional action: The operation amount acts proportionally to the error. When a 
temperature is lower than a proportional band, the operation amount is 
100%. When a temperature is within a proportional band, the operation 
amount decreases proportionally to the error. When the setting value is 
the same as the present value, the operation amount is 0%. 
(Error=Setting value–Present value) 
Heater: The setting value is 1000 (100°C), and K
P
 is 100 (10°C). The relation between the 
temperature and the operation amount is shown below. 
100℃
100%
   0%
Proportional 
    band
Temperature
Operation amount
Heater
90℃
 
 
Channel 
detection 
Alarm/Warning 
physical range 
interrupts 
numbers 
No