GE PACSystems RX7i

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Chapter 5. Function Block Diagram (FBD)

GFK-2950C February 2018 243

5.4 Comments

5.4.1 Text Block

The Text block is used to place an explanation in the program. When

you type in a comment, the first few words are displayed.

To increase the size of the text box and display more text, select the

box and drag one of the handles.

There are no operands for the Text block.

▪ Editing a comment makes the Programmer lose equality.

▪ Comment text is downloaded to the controller and retrieved upon Logic Upload.

Main Page

Default Chapter4
- Table of Contents4
- Table of Figures15
Chapter 1 Introduction16
Revisions in this Manual17
Pacsystems Programming and Configuration18
Migrating Series 90 Applications to Pacsystems18
Pacsystems Documentation19
Chapter 2 Program Organization20
Structure of a Pacsystems Application Program21
- Blocks21
- Functions and Function Blocks21
- How Blocks Are Called22
- Nested Calls22
- Types of Blocks23
- Figure 1: Conditional Block Call23
- Figure 2: Block Call with Parameters24
- Figure 3: Defining Member Variables for a User-Defined Function Block26
- Figure 4: Creating a User-Defined Function Block27
- Figure 5: Use of User-Defined Function Block in Ladder Logic27
- Figure 6: Display of Instance Data Structures27
- Figure 7: Calling an External Block in Ladder Logic30
- Local Data33
- Figure 8: Relationship of %L & %P to Program Blocks33
- Figure 9: Local Data (%L) Usage by Program Blocks33
- Parameter Passing Mechanisms34
- Figure 10: Parameter Passing Example34
- Languages36
- Figure 11: Explanation of Ladder Diagram Rung36
- Figure 12: Illustration of Function Block Diagram37
Controlling Program Execution39
Interrupt-Driven Blocks40
- Interrupt Handling41
- Figure 13: Conflict Avoidance When Using Interrupt-Driven Blocks41
- Timed Interrupts42
- I/O Interrupts42
- Module Interrupts42
- Interrupt Block Scheduling43
Chapter 3 Program Data44
Variables45
- Mapped Variables45
- Symbolic Variables46
- I/O Variables47
- Arrays49
- Variable Indexes and Arrays49
Reference Memory52
- Word (Register) References52
- Bit (Discrete) References54
User Reference Size and Default55
- G User References and CPU Memory Locations55
Genius Global Data56
Transitions and Overrides57
Retentiveness of Logic and Data58
Data Scope59
System Status References60
- S References61
- SA, %SB, and %SC References62
- Fault References64
How Program Functions Handle Numerical Data66
- Data Types66
- Floating Point Numbers68
User Defined Types (Udts)70
- Working with Udts70
- UDT Properties70
- UDT Limits71
- RUN Mode Store of Udts71
- UDT Operational Notes72
Operands for Instructions73
Word-For-Word Changes75
- Exception: Symbolic Variables75
Chapter 4 Ladder Diagram (LD) Programming76
Advanced Math Functions77
- Exponential/Logarithmic Functions78
- Square Root79
- Trig Functions80
- Inverse Trig - ASIN, ACOS, and ATAN81
Bit Operation Functions82
- Data Lengths for the Bit Operation Functions83
- Bit Position84
- Bit Sequencer85
- Bit Set, Bit Clear88
- Bit Test89
- Logical AND, Logical OR, and Logical XOR90
- Logical NOT92
- Masked Compare93
- Rotate Bits96
- Shift Bits97
Coils99
- Coil Checking99
- Graphical Representation of Coils100
- Set Coil, Reset Coil101
- Transition Coils102
Contacts106
- Continuation Contact107
- Fault Contact108
- High and Low Alarm Contacts109
- No Fault Contact110
- Normally Closed and Normally Open Contacts111
- Transition Contacts112
Control Functions117
- Do I/O118
- Edge Detectors121
- Drum123
- For Loop127
- Mask I/O Interrupt129
- Read Switch Position130
- Scan Set IO131
- Suspend I/O132
- Suspend or Resume I/O Interrupt133
Conversion Functions134
- Convert Angles135
- Convert UINT or INT to BCD4136
- Convert DINT to BCD8137
- Convert BCD4, UINT, DINT, or REAL to INT138
- Convert BCD4, INT, DINT, or REAL to UINT140
- Convert BCD8, UINT, INT, REAL or LREAL to DINT142
- Convert BCD4, BCD8, UINT, INT, DINT, and LREAL to REAL144
- Convert REAL to LREAL146
- Convert DINT to LREAL146
- Truncate147
Counters148
- Data Required for Counter Function Blocks148
- Down Counter150
- Up Counter151
Data Move Functions153
- Array Size155
- Array Size Dimension Function Blocks156
- Block Clear158
- Block Move159
- BUS_ Functions160
- Communication Request (COMMREQ)166
- Data Initialization171
- Data Initialize ASCII172
- Data Initialize Communications Request173
- Data Initialize DLAN174
- Move175
- Move Data177
- Move Data Explicit178
- Move from Flat179
- Move to Flat181
- Shift Register183
- Size of185
- Swap186
Data Table Functions187
- Array Move189
- Array Range191
- FIFO Read193
- FIFO Write195
- LIFO Read197
- LIFO Write198
- Search199
- Sort201
Math Functions204
- Overflow205
- Absolute Value206
- Add207
- Divide209
- Modulus211
- Multiply212
- Scale214
- Subtract215
Program Flow Functions216
- Argument Present217
- Call218
- Comment221
- Jumpn222
- Master Control Relay/End Master Control Relay223
- Wires225
Relational Functions226
- Compare227
- Equal, Not Equal, Greater or Equal, Greater Than, Less or Equal, Less than228
- Eq_Data229
- Range230
Timers231
- Timed Contacts231
- Timer Function Blocks232
- Standard Timer Function Blocks243
Chapter 5 Function Block Diagram (FBD)248
Note on Reentrancy249
Advanced Math Functions250
- EXPT Function252
Bit Operation Functions253
- Logical AND, Logical OR, and Logical XOR255
- Logical NOT257
Comments258
- Text Block258
Comparison Functions259
- Equal, Not Equal, Greater or Equal, Greater Than, Less or Equal, Less than261
Control Functions262
Counters264
Data Move Functions265
- Fan out269
- Move Data270
Math Functions272
- Overflow273
- Add274
- Divide275
- Modulus276
- Multiply277
- Negate278
- Subtract279
Program Flow Functions280
Timers281
- Built-In Timer Function Blocks281
- Standard Timer Function Blocks282
Type Conversion Functions283
- Convert WORD to INT285
- Convert WORD to UINT286
- Convert DWORD to DINT287
- Convert INT or UINT to WORD288
- Convert DINT to DWORD289
Chapter 6 Service Request Function290
Operation of SVC_REQ Function291
- Ladder Diagram291
- Function Block Diagram292
SVC_REQ 1: Change/Read Constant Sweep Timer293
- To Disable Constant Sweep Mode293
- To Enable Constant Sweep Mode and Use the Old Timer Value293
- To Enable Constant Sweep Mode and Use a New Timer Value293
- To Change the Timer Value Without Changing the Selection for Sweep Mode State293
- To Read the Current Timer State and Value Without Changing Either294
SVC_REQ 2: Read Window Modes and Time Values295
SVC_REQ 3: Change Controller Communications Window Mode296
- To Disable the Controller Communications Window296
- To Re-Enable or Change the Controller Communications Window Mode296
SVC_REQ 4: Change Backplane Communications Window Mode and Timer Value297
- To Disable the Backplane Communications Window297
- To Enable the Backplane Communications Window Mode297
SVC_REQ 5: Change Background Task Window Mode and Timer Value298
- To Disable the Background Task Window298
- To Enable the Background Task Window Mode298
SVC_REQ 6: Change/Read Number of Words to Checksum299
- To Read the Word Count299
- To Set a New Word Count299
SVC_REQ 7: Read or Change the Time-Of-Day Clock301
- Parameter Block Formats301
SVC_REQ 8: Reset Watchdog Timer309
SVC_REQ 9: Read Sweep Time from Beginning of Sweep310
SVC_REQ 10: Read Target Name311
SVC_REQ 11: Read Controller ID312
SVC_REQ 12: Read Controller Run State313
SVC_REQ 13: Shut down (STOP) CPU314
SVC_REQ 14: Clear Controller or I/O Fault Table315
SVC_REQ 15: Read Last-Logged Fault Table Entry316
SVC_REQ 16: Read Elapsed Time Clock319
SVC_REQ 17: Mask/Unmask I/O Interrupt321
- Masking/Unmasking Module Interrupts321
SVC_REQ 18: Read I/O Forced Status323
SVC_REQ 19: Set Run Enable/Disable324
SVC_REQ 20: Read Fault Tables325
- Non-Extended Formats326
- Extended Formats329
SVC_REQ 21: User-Defined Fault Logging334
SVC_REQ 22: Mask/Unmask Timed Interrupts336
SVC_REQ 23: Read Master Checksum337
SVC_REQ 24: Reset Module338
SVC_REQ 25: Disable/Enable EXE Block and Standalone C Program Checksums339
SVC_REQ 29: Read Elapsed Power down Time340
SVC_REQ 32: Suspend/Resume I/O Interrupt341
SVC_REQ 45: Skip Next I/O Scan342
SVC_REQ 50: Read Elapsed Time Clock343
SVC_REQ 51: Read Sweep Time from Beginning of Sweep345
SVC_REQ 56: Logic Driven Read of Nonvolatile Storage346
- Discrete Memory346
- Storage Disabled Conditions346
- Maximum of One Active Instruction346
- ENO and Power Flow to the Right346
- Parameter Block347
SVC_REQ 57: Logic Driven Write to Nonvolatile Storage350
- Length of Data Written350
- Write Frequency350
- Erase Cycles351
- Discrete Memory351
- Retentiveness351
- Maximum of One Active Instruction351
- Storage Disabled Conditions351
- Error Checking351
- Fragmentation352
- When Nonvolatile Storage Is Full352
- Equality353
- Redundancy353
- ENO and Power Flow to the Right353
- Parameter Block for SVC_REQ 57354
Chapter 7 PID Built-In Function Block358
- Figure 14: PID in Ladder Diagram358
- Figure 15: PID in Function Block Diagram358
Operands of the PID Function359
- Operands for LD Version of PID Function Block359
- Operands for FBD Version of PID Function Block360
Reference Array for the PID Function361
- Scaling Input and Outputs361
- Reference Array Parameters362
Operation of the PID Function368
- Automatic Operation368
- Manual Operation368
- Time Interval for the PID Function369
PID Algorithm Selection (PIDISA or PIDIND) and Gain Calculations370
- Figure 16: PID_IND Diagram370
Determining the Process Characteristics374
Setting Tuning Loop Gains375
- Basic Iterative Tuning Approach375
- Setting Loop Gains Using the Ziegler and Nichols Tuning Approach376
- Ideal Tuning Method377
PID Example378
- Reference Array Initialization Using %M00006378
- Figure 17: PID Example Logic379
Chapter 8 Structured Text (ST) Programming380
Language Overview380
- Statements380
- Expressions380
- Operators381
- Structured Text Syntax382
Statement Types383
- Assignment Statement384
- Function Call385
- RETURN Statement388
- IF Statement389
- CASE Statement390
- For392
- WHILE Statement394
- REPEAT Statement395
- ARG_PRES Statement396
- Exit Statement397
Chapter 9 Diagnostics398
Fault Handling Overview399
- System Response to Faults399
- Fault Tables399
- Fault Actions and Fault Action Configuration400
Using the Fault Tables401
- Controller Fault Table401
- Figure 18: Controller Fault Table Display401
- Figure 19: Detail Information for Controller Fault Entry402
- I/O Fault Table403
- Figure 20: I/O Fault Table Display403
- Figure 21: I/O Fault Table Fault Entry Detail Display404
System Handling of Faults405
- System Fault References406
- Using Fault Contacts409
- Using Point Faults411
- Using Alarm Contacts411
Controller Fault Descriptions and Corrective Actions412
- Controller Fault Groups412
- Loss of or Missing Rack (Group 1)413
- Loss of or Missing Option Module (Group 4)414
- Addition Of, or Extra Rack (Group 5)414
- Reset Of, Addition Of, or Extra Option Module (Group 8)415
- System Configuration Mismatch (Group 11)416
- System Bus Error (Group 12)422
- CPU Hardware Failure (Group 13)423
- Module Hardware Failure (Group 14)424
- Option Module Software Failure (Group 16)425
- Program or Block Checksum Failure (Group 17)426
- Battery Status (Group 18)427
- Constant Sweep Time Exceeded (Group 19)428
- System Fault Table Full (Group 20)428
- I/O Fault Table Full (Group 21)428
- User Application Fault (Group 22)429
- CPU Over-Temperature (Group 24)431
- Power Supply Fault (Group 25)431
- No User Program on Power-Up (Group 129)431
- Corrupted User Program on Power-Up (Group 130)432
- Window Completion Failure (Group 131)432
- Password Access Failure (Group 132)433
- Null System Configuration for RUN Mode (Group 134)433
- CPU System Software Failure (Group 135)434
- Communications Failure During Store (Group 137)436
- Non-Critical CPU Software Event (Group 140)437
I/O Fault Descriptions and Corrective Actions439
- Fault Extra Data439
- I/O Fault Groups439
- I/O Fault Categories440
- Circuit Faults (Category 1)443
- Loss of Block (Category 2)448
- Addition of Block (Category 3)449
- I/O Bus Fault (Category 6)450
- Module Fault (Category 8)451
- Addition of IOC (Category 9)452
- Loss of or Missing IO Controller (Category 10)452
- IOC (I/O Controller) Software Fault (Category 11)453
- Forced and Unforced Circuit (Categories 12 and 13)453
- Loss of or Missing I/O Module (Category 14)454
- Addition of I/O Module (Category 15)454
- Extra I/O Module (Category 16)454
- Extra Block (Category 17)455
- IOC Hardware Failure (Category 18)455
- GBC Stopped Reporting Faults (Category 19)455
- GBC Software Exception (Category 21)456
- Block Switch (Category 22)457
- Reset of IOC (Category 27)457
Diagnostic Logic Blocks (Dlbs)458
- DLB Operation459
- Figure 22: Diagnostic Logic Blocks (Dlbs) Assigned to Target in MPE459
- Executing Dlbs461
- Figure 23: Properties of Diagnostic Logic Block (DLB)461
- Figure 24: DLB Heartbeat Setting461
- Diagnostic Logic Block (DLB) Example465
- Figure 25: Drag DLB from Toolchest and Drop in Active Blocks Node467
- Figure 26: Set DLB Execution Mode to Sweep (Properties Tab)467
- Figure 27: Start DLB Execution467
- Figure 28: Initialize Local Symbolic Variables468
- Figure 29: DLB Icon and Status Bar after Execution Has Commenced468
- Figure 30: Data Watch for DLB Variables468

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