Mitsubishi MELSEC-F FX3U Series User Manual

11
FX 3U /FX 3UC Series PLC User's Manual - Analog Control Edition
Table of Contents
PID Instruction (FNC 88)
1. Outline G-3
1.1 Outline of function ....................................................................................................................... G-3
1.2 Basic Operation Expressions in PID Instruction (Reference)...................................................... G-4
2. How to Use PID Instruction G-5
2.1 Explanation of function and operation......................................................................................... G-5
2.2 Relationship Between Parameter Setting and Auto Tuning........................................................ G-6
3. Parameter G-7
3.1 Parameter List: (S3) to (S3) + 28 .............................................................................................. G-7
3.2 Details of Parameters.................................................................................................................. G-9
3.2.1 Sampling time (TS): (S3) ............................................................................................................. G-9
3.2.2 Operation setting (ACT):(S3)+1................................................................................................. G-10
3.2.3 Input filter (α): (S3)+2 ................................................................................................................ G-12
3.2.4 Proportional gain (K
P): (S3)+3................................................................................................... G-13
3.2.5 Integral time (T
I): (S3)+4 ........................................................................................................... G-13
3.2.6 Differential gain (K
D): (S3)+5..................................................................................................... G-15
3.2.7 Differential time (T
D): (S3)+6..................................................................................................... G-15
3.2.8 Alarm output flag: (S3)+24 ........................................................................................................ G-17
4. Auto Tuning G-18
4.1 Limit Cycle Method.................................................................................................................... G-18
4.1.1 Parameters set in auto tuning (of limit cycle method)................................................................ G-18
4.1.2 Auto tuning procedure ............................................................................................................... G-19
4.1.3 Reference: How to obtain three constants in PID control (limit cycle method).......................... G-20
4.2 Step Response Method............................................................................................................. G-21
4.2.1 Parameters to be set by auto-tuning (step response method) .................................................. G-21
4.2.2 Auto tuning procedure ............................................................................................................... G-21
4.2.3 Reference: How to obtain three constants in PID control (step response method)................... G-22
4.3 Cautions on Auto Tuning Execution..........................................................................................G-22
5. Example of Practical Programs (for Step Response Method) G-23
5.1 Example: System and operation ............................................................................................... G-23
5.2 Program example of auto tuning (step response method) and PID control .............................. G-24
5.3 Program example of auto tuning (step response method) ........................................................ G-26
6. Troubleshooting G-28
6.1 Error Codes............................................................................................................................... G-28
Warranty...................................................................................................................................... i
Revised History ......................................................................................................................... ii

Mitsubishi MELSEC-F FX3U Series Specifications

General

Brand	Mitsubishi
Model	MELSEC-F FX3U Series
Category	Controller
Language	English