IDEC MICROSmart FC6A-C24R1CE - Page 399

FC6A S ERIES MICROS MART L ADDER P ROGRAMMING M ANUAL FC9Y-B1726 19-9
19: PID C ONTROL I NSTRUCTION
Upper/Lower Limit
Range Alarm
Turns ON the alarm output when (set point - alarm
value) ≤ process variable ≤ (set point + alarm value).
Turns OFF the alarm output when process variable ≥
(set point + alarm value + hysteresis).
Turns OFF the alarm output when process variable ≤
(set point - alarm value - hysteresis).
When (set point + alarm value) < process variable <
(set point + alarm value + hysteresis), the alarm
output maintains the state of the previous scan.
When (set point - alarm value - hysteresis) < process
variable < (set point - alarm value), the alarm output
maintains the state of the previous scan.
Set point: 200.0°C
Alarm value: 5.0°C
Hysteresis: 2.0°C
When 195.0°C ≤ process variable ≤ 205.0°C, the alarm output is turned ON.
When process variable ≥ 207 .0 °C, the alarm output is turned OFF.
When process variable ≤ 193.0°C, the alarm output is turned OFF.
Process High Alarm
Turns ON the alarm output when process variable ≥
alarm value.
Turns OFF the alarm output when process variable ≤
(alarm value - hysteresis).
When (alarm value - hysteresis) < process variable <
alarm value, the alarm output maintains the state of
the previous scan.
Alarm value: 205.0°C
Hysteresis: 2.0°C
When process variable ≥ 205 .0 °C, the alarm output is turned ON.
When process variable ≤ 203 .0 °C, the alarm output is turned OFF.
Process Low Alarm
Turns ON the alarm output when process variable ≤
alarm value.
Turns OFF the alarm output when process variable ≥
(alarm value + hysteresis).
When alarm value < process variable < (alarm value
+ hysteresis), the alarm output maintains the state of
the previous scan.
Alarm value: 195.0°C
Hysteresis: 2.0°C
When process variable ≤ 195 .0 °C, the alarm output is turned ON.
When process variable ≥ 197 .0 °C, the alarm output is turned OFF.
Upper Limit Alarm
with Standby
Turns ON the alarm output when process variable ≥
(set point + alarm value).
Turns OFF the alarm output when process variable ≤
(set point + alarm value - hysteresis).
When (set point + alarm value - hysteresis) < process
variable < (set point + alarm value), the alarm output
maintains the state of the previous scan.
The gray-colored portion is where the standby
function operates.
Set point: 200.0°C
Alarm value: 5.0°C
Hysteresis: 2.0°C
When process variable ≥ 205 .0 °C, the alarm output is turned ON.
When process variable ≤ 203.0°C, the alarm output is turned OFF.
Type Action Example
OFF
ON
Alarm action pointSet point
Hysteresis
Alarm value Alarm value
Hysteresis
Alarm action point
OFF
ON
193.0°C 207.0°C195.0°C 205.0°C200.0°C
2.0°C
5.0°C
2.0°C
5.0°C
OFF
ON
Alarm action point
Hysteresis
OFF
ON
205.0°C203.0°C
2.0°C
OFF
ON
Alarm action point
Hysteresis
OFF
ON
197.0°C195.0°C
2.0°C
OFF
ON
+ Alarm action pointSet point
Hysteresis
Alarm value
- Alarm action point
OFF
ON
205.0°C203.0°C200.0°C
2.0°C
5.0°C