5-52
5-12-3
Process alarm
Process control performance is generally determined by how close the process variable is to the set point. Most of the process
controls that are actually running are continuous operation, and if an error condition occurs, PV control is lost. Process alarms
are mandatory for early detection of control error conditions, and if an error occurs, an alarm is sounded to allow the PID
control to be manually controlled or other measures to be taken until the condition is restored.
The SJ-Ether CPU provides up-to-date alarm functions for PID control.
PV absolute value alarm
Set the lower limit (2 pieces) and the upper limit (2 pieces) to monitor the PV value. When the PV
value exceeds these programmed limits, an alarm is generated.
PV deviation alarm
Monitor the PV value by comparing with the SP. If the difference between the PV and SP exceeds the
programmed alarm value, an alarm is generated.
PV change rate alarm
Calculate the rate of change of PV and generate an alarm when the programmed alarm quantity is
exceeded.
Alarm hysteresis
Alarm is linked to absolute and deviation alarms to suppress "noisy sounds" of alarms that may occur
near the alarm threshold.
The alarm threshold can be programmed variable. Each alarm can be monitored completely
independently.
The following figure shows the PV monitoring function. The alarm is enabled/disabled by the PID mode setting 1 R + 00 bits
12-14 in the control parameter. The KPP PID Monitor Settings dialog screen provides easy programming, enabling, and
monitoring of alarms. In the ladder circuit, the arm can be monitored by checking the PID mode of the control table and bits 3
to 9 of the alarm condition R+06.
Unlike PID calculations, alarms always work as long as the CPU is in RUN mode. The control mode can be either manual,
automatic, or vertical. In addition, if the enabled bits listed above are set to "1", the alarm will function.
Note: DirectSOFT4 and DirectSOFT5 are not supported.
Be sure to use KPP Ver1. 5.0.0 or higher.
+
–
0
1
3
4
5
6
7
8
9
10
11
12
13
14
15
2
1
0
0
1
3
4
5
6
7
8
9
10
11
12
13
14
15
2
1
0
1
0
ループ演算
PID
モード設定
1
ループ演算
PID
アラームワード
セットポイント
偏差
制御出力
プロセス変数
PV
値
PV
偏差
PV
変化率
アラームの有効
アラーム監視
アラームビット
アラーム有効ビット
ビット
ビット
Loop
calculation
Set point
Control
output
Deviation
Process variable
Loop calculation
PV value
PV deviation
PV rate of change
Alarm valid
Alarm monitoring
Valid alarm bit
Alarm bit
PID mode setting 1
PID alarm word
Bit
Bit
Summary of Contents for Kostac SJ-Ether Series
Page 1: ...English version of the KOSTAC SJ Ether series user s manual SJ ETHER USER M...
Page 12: ......
Page 13: ...1...
Page 14: ......
Page 88: ......
Page 89: ......
Page 113: ...3 24 Note Refer to 6 3 3 Module Assembly for connections and locks between modules...
Page 153: ......
Page 156: ...flashing OFF Not sent H W RX Green flashing Receiving H W OFF Not received H W...
Page 161: ...4 8...
Page 221: ......
Page 310: ...Chapter 7 Maintenance...
Page 311: ......