GE PACSystems RX7i - Page 12

Contents
GFK-2950C February 2018 ix
7.5 Determining the Process Characteristics ....................................................................... 359
7.6 Setting Tuning Loop Gains .................................................................................................. 360
7.6.1 Basic Iterative Tuning Approach ...................................................................................................................... 360
7.6.2 Setting Loop Gains Using the Ziegler and Nichols Tuning Approach ................................................ 361
7.6.3 Ideal Tuning Method ............................................................................................................................................. 362
7.7 PID Example ........................................................................................................................... 363
7.7.1 Reference Array Initialization using %M00006 .......................................................................................... 363
Chapter 8 Structured Text (ST) Programming .................................................................................... 365
8.1 Language Overview .............................................................................................................. 365
8.1.1 Statements ............................................................................................................................................................... 365
8.1.2 Expressions .............................................................................................................................................................. 365
8.1.3 Operators .................................................................................................................................................................. 366
8.1.4 Structured Text Syntax ........................................................................................................................................ 367
8.2 Statement Types ................................................................................................................... 368
8.2.1 Assignment Statement ....................................................................................................................................... 369
8.2.2 Function Call ............................................................................................................................................................ 370
8.2.3 RETURN Statement ............................................................................................................................................... 373
8.2.4 IF Statement ............................................................................................................................................................ 374
8.2.5 CASE Statement ..................................................................................................................................................... 375
8.2.6 FOR … DO Statements.......................................................................................................................................... 377
8.2.7 WHILE Statement .................................................................................................................................................. 379
8.2.8 REPEAT Statement ................................................................................................................................................ 380
8.2.9 ARG_PRES Statement .......................................................................................................................................... 381
8.2.10 Exit Statement ........................................................................................................................................................ 382
Chapter 9 Diagnostics ............................................................................................................................... 383
9.1 Fault Handling Overview ..................................................................................................... 384
9.1.1 System Response to Faults ............................................................................................................................... 384
9.1.2 Fault Tables .............................................................................................................................................................. 384
9.1.3 Fault Actions and Fault Action Configuration ............................................................................................ 385
9.2 Using the Fault Tables ......................................................................................................... 386
9.2.1 Controller Fault Table .......................................................................................................................................... 386
9.2.2 I/O Fault Table ......................................................................................................................................................... 388
9.3 System Handling of Faults .................................................................................................. 390
9.3.1 System Fault References .................................................................................................................................... 391
9.3.2 Using Fault Contacts ............................................................................................................................................ 394
9.3.3 Using Point Faults .................................................................................................................................................. 396
9.3.4 Using Alarm Contacts .......................................................................................................................................... 396