GE PACSystems RX7i

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Chapter 4. Ladder Diagram (LD) Programming

GFK-2950C February 2018 155

The programming logic displayed in example 2 can be simplified by replacing the six MOVE functions

with one DATA_INIT_COMM function.

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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

GE PACSystems RX7i - Page 170

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