YOKOGAWA DpharpEJX vigilantplant EJX Series - Page 5

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CONTENTS
IM 01C25T02-01E
Appendix 4. Arithmetic (AR) Block .............................................................. A-35
A4.1 Arithmetic Function Block Schematic ............................................... A-35
A4.2 Input Section .....................................................................................A-36
A4.2.1 Main Inputs ................................................................................. A-36
A4.2.2 Auxiliary Inputs ........................................................................... A-36
A4.2.3 INPUT_OPTS .............................................................................A-37
A4.2.4 Relationship between the Main Inputs and PV.......................... A-37
A4.3 Computation Section .........................................................................A-38
A4.3.1 Computing Equations ................................................................. A-38
A4.3.2 Compensated Values ................................................................. A-38
A4.3.3 Average Calculation ...................................................................A-38
A4.4 Output Section .................................................................................. A-38
A4.4.1 Mode Handling ...........................................................................A-39
A4.4.2 Status Handling .......................................................................... A-39
A4.5 List of the Arithmetic Block Parameters ........................................... A-40
APPENDIX 5. PID BLOCK .............................................................................. A-42
A5.1 Function Diagram ..............................................................................A-42
A5.2 Functions of PID Block ..................................................................... A-42
A5.3 Parameters of PID Block .................................................................. A-43
A5.4 PID Computation Details................................................................... A-45
A5.4.1 PV-proportional and -derivative Type PID (I-PD) Control
Algorithm .................................................................................... A-45
A5.4.2 PID Control Parameters ............................................................. A-45
A5.5 Control Output ................................................................................... A-45
A5.5.1 Velocity Type Output Action....................................................... A-45
A5.6 Direction of Control Action ................................................................ A-45
A5.7 Control Action Bypass....................................................................... A-45
A5.8 Feed-forward .....................................................................................A-46
A5.9 Block Modes...................................................................................... A-46
A5.9.1 Mode Transitions ........................................................................ A-46
A5.10Bumpless Transfer ............................................................................ A-47
A5.11Setpoint Limiters ............................................................................... A-47
A5.11.1 When PID Block Is in Auto Mode ............................................ A-47
A5.11.2 When PID Block Is in Cas or RCas Mode............................... A-47
A5.12External-output Tracking ................................................................... A-47
A5.13Measured-value Tracking.................................................................. A-47
A5.14Initialization and Manual Fallback (IMan) .........................................A-48
A5.15Manual Fallback ................................................................................ A-48
A5.16Auto Fallback .................................................................................... A-48
A5.17Mode Shedding upon Computer Failure........................................... A-49
A5.17.1 SHED_OPT ..............................................................................A-49
A5.18Alarms ...............................................................................................A-49
A5.18.1 Block Alarm (BLOCK_ALM) ..................................................... A-49
A5.18.2 Process Alarms ........................................................................A-49
A5.19Example of Block Connections ......................................................... A-50
A5.20View Object for PID Function Block ................................................. A-50