Siemens CPU 948 Operating instructions

Contents
Introduction 1
User Program 2
Program Execution 3
Operating Statuses and Program
Execution Levels 4
Interrupt and Error Diagnostics 5
Integrated Special Functions 6
Extended Data Block DX 0 7
Memory Assignment and Memory
Organization 8
Memory Access Using Absolute
Addresses 9
Multiprocessor Mode and Com-
munication in the S5-155U 10
PG Interfaces and Functions 11
Appendix 12
Indexes:
Abbreviations
Key Words 13
The List of Operations, order no.
6ES5 997-3UA22, is included
with this manual.
10/98
C79000-G8576-C848
Release 04
S5-155U
CPU 948
Programming Guide
This manual has the order number:
6ES5 998–3PR21
SIMATIC S5

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Correct Usage
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!Warning
Thisdeviceanditscomponentsmayonly be usedfortheapplicationsdescribedinthecatalog or thetechnical
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Safety Guidelines
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1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 1 - 3
1.1 Area of Application for the S5-155U with the CPU 948 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4
1.2 Typical Mode of Operation of a CPU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 5
1.3 The Programs in a CPU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 7
1.4 Which Operands are available to the User Program?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 11
1.5 How much Memory is available for the User Program? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 14
1.6 How to Tackle Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 15
1.7 Programming Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 18
1.8 Converting User Programs of the CPU 928B for the CPU 948. . . . . . . . . . . . . . . . . . . . . . . . . 1 - 19
2 User Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3
2.1 STEP 5 Programming Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 4
2.1.1 The LAD, CSF, STL Methods of Representation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 4
2.1.2 Structured Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 5
2.1.3 STEP 5 Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 6
2.1.4 Number Representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 8
2.1.5 STEP 5 Blocks and Storing them in Memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 12
2.2 Program, Organization and Sequence Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 16
2.2.1 Organization Blocks as User Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 18
2.2.2 Organization Blocks for Special Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 22
2.3 Function Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 23
2.3.1 Structure of Function Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 24
2.3.2 Programming Function Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 26
2.3.3 Calling Function Blocks and Assigning Parameters to them . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 28
2.3.4 Special Function Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 33
2.4 Data Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 35
2.4.1 Creating Data Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 37
2.4.2 Opening Data Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 38
2.4.3 Special Data Blocks. . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . 2 - 41
Contents
CPU 948 Programming Guide
C79000-G8576-C848-04 iii

3 Program Execution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3
3.1 Principle of Program Execution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4
3.2 Program Organization . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . 3 - 5
3.3 Storing Program and Data Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 10
3.4 Processing the User Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 11
3.4.1 Definition of Terms used in Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 12
3.5 STEP 5 Operations with Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 15
3.5.1 Basic Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 19
3.5.2 Programming Examples in the STL, LAD and CSF Methods of Representation. . . . . . . . . . . 3 - 34
3.5.3 Supplementary Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 49
3.5.4 Executive Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 59
3.5.5 Semaphore Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 75
4 Operating Statuses and Program Execution Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 3
4.1 Program Execution Levels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4
4.2 STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 9
4.2.1 SOFT STOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 9
4.2.2 HARD STOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 13
4.2.3 OVERALL RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 14
4.3 START-UP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 16
4.3.1 MANUAL and AUTOMATIC COLD RESTART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 17
4.3.2 MANUAL and AUTOMATIC WARM RESTART. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 18
4.3.3 Comparison between COLD RESTART and WARM RESTART . . . . . . . . . . . . . . . . . . . . . . . 4 - 21
4.3.4 RETENTIVE COLD RESTART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 22
4.3.5 Comparison of COLD RESTART and RETENTIVE COLD RESTART . . . . . . . . . . . . . . . . . 4 - 23
4.3.6 User Interfaces for Start-Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 24
4.3.7 Extended AUTOMATIC WARM RESTART with the CPU 948 (HOT RESTART). . . . . . . . . 4 - 27
4.3.8 Interruptions during START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 28
4.4 RUN Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 29
4.4.1 Cyclic Program Execution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 30
4.4.2 Specifying Time and Interrupt-Driven Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 32
4.4.3 Time-Controlled Program Execution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 33
4.4.4 Interrupt-Driven Program Execution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 41
5 Interrupt and Error Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3
5.1 Frequent Errors in the User Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 4
5.2 Error Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 5
5.3 Procedure for Error Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 8
5.4 Control Bits and Interrupt Stack . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . 5 - 9
5.4.1 Control Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 10
5.4.2 ISTACK Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 14
5.4.3 Example of Error Diagnosis using the ISTACK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 19
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CPU 948 Programming Guide
iv C79000-G8576-C848-04

5.5 Error Handling Using Organization Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 20
5.6 Causes of Error and Reactions of the CPU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 23
5.6.1 OB 19: Calling a Logic Block That Is Not Loaded (KB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 24
5.6.2 OB 19: Calling a Data Block That Is Not Loaded (KDB). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 24
5.6.3 OB 23/24, OB 28/29:Timeout Error (QVZ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 25
5.6.4 OB 25: Addressing Error (ADF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 26
5.6.5 OB 26: Cycle Time Exceeded Error (ZYK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 27
5.6.6 OB 27: (Substitution Error SUF). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 28
5.6.7 OB 30: Parity Error and Timeout Error in the User Memory (PARE) . . . . . . . . . . . . . . . . . . . 5 - 28
5.6.8 OB 32: Load and Transfer Error (TRAF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 29
5.6.9 OB 33: Collision of Timed Interrupts Error (WEFES/WEFEH) . . . . . . . . . . . . . . . . . . . . . . . . 5 - 30
5.6.10 OB 34: Error with G DB/GX DX (FEDBX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 32
5.6.11 OB 35: Communication Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 32
5.6.12 OB 36: Error in Self-test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 33
5.7 Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 34
5.7.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 34
5.7.2 Description of the Test Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 35
5.7.3 Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 37
5.7.4 Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 38
6 Integrated Special Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 3
6.1 Introduction . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . 6 - 4
6.2 OB 121: Set/Read System Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 8
6.3 OB 122: "Disable Interrupts" On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 12
6.4 OB 124: Delete STEP 5 Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 14
6.5 OB 125: Generate STEP 5 Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 17
6.6 OB 126: Define, Transfer Process Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 20
6.7 OB 129: Battery State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 25
6.8 OB 131: Delete ACCUs 1, 2, 3 and 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 26
6.9 OB 132/133: Roll-Up ACCU/Roll-Down ACCU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 27
6.10 OB 141: "Disable Single Cyclic Timed Interrupts" On/Off. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 29
6.11 OB 142: "Delay All Interrupts" On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 32
6.12 OB 143: "Delay Single Cyclic Timed Interrupts" On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 35
6.13 OB 150: Set/Read System Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 38
6.14 OB 151: Set/Read Time for Clock-Controlled Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 43
6.15 OB 153: Set/Read Time for Delayed Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 50
6.16 OB 180: Variable Data Block Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 53
6.17 OB 181: Test Data Blocks (DB/DX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 57
6.18 OB 182: Copy Data Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 59
6.19 OB 202 to 205: Multiprocessor Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 62
Contents
CPU 948 Programming Guide
C79000-G8576-C848-04 v

6.20 OB 222: Restart Cycle Monitoring Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 63
6.21 OB 223: Compare Start-Up Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 64
6.22 OB 254/255: Copy/Duplicate Data Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 65
7 Extended Data Block DX 0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 3
7.1 Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 4
7.2 Structure of DX 0. . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . . . . . . 7 - 5
7.2.1 Example of Input in DX 0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 7
7.3 Parameters for DX 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 8
7.4 Examples of Parameter Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 12
7.4.1 STEP 5 Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 12
7.4.2 Parameter Assignment using the PG Screen Form. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 - 14
8 Memory Assignment and Memory Organization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 3
8.1 Structure of the Memory Area. . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . 8 - 4
8.2 Memory Assignment in the CPU 948 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 5
8.2.1 Memory Assignment for the System RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 6
8.2.2 Memory Assignment for the Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 8
8.3 User Memory Organization in the CPU 948. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 10
8.3.1 Block Headers in User Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 12
8.3.2 Block Address List in Data Block DB 0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 13
8.3.3 RI/RJ Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 14
8.3.4 RS/RTArea. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 15
8.3.5 Bit Assignment of the System Data Words. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 18
8.3.6 Addressable System Data Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 42
9 Memory Access Using Absolute Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 3
9.1 Introduction . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . 9 - 4
9.2 Memory Access via Address in ACCU 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 8
9.2.1 LIR/TIR: Loading to or Transferring from a 16-Bit Memory Area Indirectly . . . . . . . . . . . . . . 9 - 9
9.2.2 Examples of Access to DW > 255 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 15
9.2.3 LDI/TDI: Loading to or Transferring from a 32-Bit Memory Area Indirectly . . . . . . . . . . . . . 9 - 17
9.3 Transferring Memory Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 19
9.4 Operations with the Base Address Register (BR Register) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 22
9.4.1 Operations for Transfer between Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 23
9.4.2 Accessing the Local Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 24
9.4.3 Accessing the Global Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 25
9.4.4 Accessing the Dual-Port RAM Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 29
10 Multiprocessor Mode and Communication in the S5-155U . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 3
10.1 Multiprocessor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 4
10.1.1 When to use the Multiprocessor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 4
10.1.2 What Communications Mechanisms are Available?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 4
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10.1.3 Exchanging Data via IPC Flags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 5
10.1.4 Exchanging Data via Handling Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 8
10.1.5 What needs to be Programmed for the Multiprocessor Mode? . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 9
10.1.6 How to Create Data Block DB 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 9
10.1.7 Starting up in the Multiprocessor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 13
10.1.8 Test Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 10 - 14
10.2 Multiprocessor Communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 15
10.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 15
10.2.2 How the Transmitter and Receiver are Identified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 16
10.2.3 Why Data is Buffered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 17
10.2.4 How the Buffer is Processed and Managed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 18
10.2.5 System Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 21
10.2.6 Calling Communication OBs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 22
10.2.7 How to Assign Parameters to Communication OBs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 23
10.2.8 How to Evaluate the Output Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 24
10.3 Runtimes of the Communication OBs. .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . 10 - 31
10.4 INITIALIZE Function (OB 200). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 33
10.4.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 33
10.4.2 Call Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 35
10.4.3 Input Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 35
10.4.4 Output Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 38
10.5 SEND Function (OB 202) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 40
10.5.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 40
10.5.2 Call Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 40
10.5.3 Input Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 40
10.5.4 Output Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 42
10.6 SEND TEST Function (OB 203) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 45
10.6.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 45
10.6.2 Call Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 45
10.6.3 Input Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 45
10.6.4 Output Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 45
10.7 RECEIVE Function (OB 204). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 47
10.7.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 47
10.7.2 Call Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 47
10.7.3 Input Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 47
10.7.4 Output Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 48
10.8 RECEIVE TEST Function (OB 205) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 51
10.8.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 51
10.8.2 Call Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 51
10.8.3 Input Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 51
10.8.4 Output Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 51
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10.9 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 53
10.9.1 Calling the Special Function OB using Function Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 53
10.9.2 Transferring Data Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 60
10.9.3 Extending the IPC Flag Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 66
11 PG Interfaces and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 3
11.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 4
11.2 PG Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 5
11.2.1 Info 11 - 6
11.2.2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 7
11.2.3 Program Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 8
11.3 Serial Link PG - PLC via 1st or 2nd Serial Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 16
11.4 Parallel Operation of Two Serial PG Interfaces . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . .. . 11 - 17
11.4.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 19
11.4.2 Operation . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . 11 - 19
11.4.3 Sequence in Certain Operating Situations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 21
11.5 PG Functions via the S5 Bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 27
11.5.1 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 27
11.5.2 How the PG Functions Work via the S5 Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 29
11.5.3 Installation and Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 31
11.5.4 Condition Codes Indicating Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 - 35
12 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 3
13 Indexes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 3
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Contents of Chapter 1
1.1 Area of Application for the S5-155U with the CPU 948 . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4
1.2 Typical Mode of Operation of a CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 5
1.3 The Programs in a CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 7
1.4 Which Operands are available to the User Program? . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 11
1.5 How much Memory is available for the User Program? . . . . . . . . . . . . . . . . . . . . . . . 1 - 14
1.6 How to Tackle Programming? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 15
1.7 Programming Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 18
1.8 Converting User Programs of the CPU 928B for the CPU 948. . . . . . . . . . . . . . . . . . 1 - 19
1
Introduction
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Contents
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1 - 2 C79000-G8576-C848-04

1Introduction
Aims of the manual This manual is intended to provide specialized information about
programming the CPU 948 for users who already have basic
knowledge of programming PLCs and want to use the CPU 948 in the
S5-155U programmable controller. If you do not yet have this basic
knowledge, we strongly advise you read the documentation
introducing the programming language STEP 5 /3/ or take part in a
course at our training center. SIEMENS provides comprehensive
training for SIMATIC S5. For more detailed information, contact your
local SIEMENS office.
Contents of Chapter 1 Chapter 1 explains how to use the manual and deals with the areas of
application of the S5-155U programmable controller with the
CPU 948 and its structure.
The chapter explains the typical mode of operation of a CPU and the
structure of the CPU program.
You will also find a few suggestions about how to tackle
programming and will learn some of the features of the CPU 948
which are important for programming.
If you have already worked with the CPU 946/947 and would like to
know the differences between these modules and the CPU 948, refer
to Section 1.8.
Chapter 1 also informs you about differences between versions A01
and A02 of the CPU 948 and explains points you should remember
when converting "928B" programs for the CPU 948.
CPU 948 Programming Guide
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1.1 Area of Application for the S5-155U with the CPU 948
SIMATIC S5 family The S5-155U programmable controller belongs to the family of
SIMATIC S5 programmable controllers. With the CPU 948, it is the
most powerful multiprocessor unit for process automation (open and
closed loop control, signalling, monitoring, logging).
Owing to its modularity and high performance, it can be used for
medium to extremely large control systems as well as for complex
automation tasks at the plant and process supervision level.
Suitability The S5-155U with the CPU 948 is particularly suitable for the
following:
•• Tasks requiring fast bit and word-oriented processing and fast
reaction times, i.e. with extremely fast open and closed loop controls.
Examples of this are fast processes in mechanical engineering
(bottling plant, packing machines or similar systems) and in the
automobile industry.
•• Tasks requiring an extremely high storage capacity and fast access
times, e.g. in the automobile industry, process and plant
engineering.
•• Tasks requiring fast communication with other CPUs installed in
the PLC and operating in the multiprocessor mode and with CP
modules (e.g. when connected to bus systems, host computers, for
visualization, operation and monitoring).
•• Complex tasks which can be handled efficiently and clearly using
the high level languages C and SCL.
Area of Application for the S5-155U with the CPU 948
CPU 948 Programming Guide
1 - 4 C79000-G8576-C848-04

1.2 Typical Mode of Operation of a CPU
Mode of operation of a CPU The following modes of operation are possible in a CPU:
Cyclic processing This is the main part of all activities in the CPU. As the name already
says, the same operations are repeated in an endless cycle.
Cyclic processing can be divided into three main phases, as follows:
Phase Sequence
1All the input modules assigned to the CPU are scanned by the system
program and the values read in are
stored in the process image of the
inputs (PII).
2Thevalues contained in the PII are processed by the user program and the
values to be output are entered in the
process image of the outputs (PIQ).
3The values contained in the process image of the outputs are output by the
system program to the output modules
assigned to the CPU.
Cyclic processing
Interrupt-driven processing
Time-controlled processing
1. 2. 3.
Read in process image
of the inputs
Output process image
of the outputs
&
&=1
I1.5
I1.6
I1.4
I1.3 Q3.1
Evaluate input signals,
set output signals
Input I 1.3
Input I 1.4
Input I 1.5
Output Q 3.1
Output Q 2.0
Output Q 4.7
CPU Process
Typical Mode of Operation of a CPU
CPU 948 Programming Guide
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Time-controlled processing In addition to the cyclic processing, time-controlled processing is
also available for processes requiring control signals at constant
intervals, e.g. non-time critical monitoring functions performed every
second.
Interrupt-driven processing If the reaction to a particular process signal must be particularly fast, this
should be handled with interrupt-driven processing. With, for example,
a system interrupt, triggered via an interrupt generating module, you
can activate a special processing section within your program.
Processing according to
priority
The types of processing listed above are handled by the CPU
according to their priority.
Since a fast reaction is required to a time or interrupt event, the CPU
interrupts cyclic processing to handle a time or interrupt event. Cyclic
processing therefore has the lowest priority.
Whether or not the time-controlled processing is more important than
the interrupt controlled processing depends, among other things, on
the particular task. For this reason, the priority of time and
interrupt-driven processing on the CPU 948 can be selected.
Typical Mode of Operation of a CPU
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1.3 The Programs in a CPU
The program existing on every CPU is divided into the following:
•• the system program
and
•• the user program.
System program The system program organizes all the functions and sequences of the
CPU which do not involve a specific control task (refer to Fig. 1-2).
Update process image
of the inputs
Output process image
of the outputs
System
program
Call
user
processing
(inter-
faces)
Execute start-up
Handle errors
Communication with
the PG
Manage memory
Fig. 1-1 Tasks of the system program
The Programs in a CPU
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Tasks The tasks include the following: 1)
•• cold and warm restart,
•• updating the process image of the inputs and outputting the
process image of the outputs,
•• calling the cyclic, time-controlled and interrupt-driven programs,
•• detection and handling of errors,
•• memory management,
•• communication with the programmer (PG).
User interfaces As the user, you can influence the reaction of the CPU to particular
situations and errors via special interfaces to the system program.
Storing the system program After switching on the power supply to the PLC (POWER UP) the
system program is read from the EPROM to the internal operating
system RAM.
System program defaults The following chapters, except for Chapter 7, describe the default
system reaction to process events or errors. Depending on the
defaults, the CPU changes to the stop mode if an operation code error
occurs and the error organization block is not loaded.
Modifying the defaults You can modify the system response by assigning parameters for the
data block DX 0.
Chapter 7 describes the system response following modification.
1) When operating with several CPUs (multiprocessing) further tasks are involved.
The Programs in a CPU
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User program
Tasks The user program contains all the functions required for processing a
specific control task. In general terms, these functions can be
assigned to the interface provided by the system program for the
various types of processing, as follows:
Type of processing Task
Cold and warm restart To provide the conditions under which
the other processing functions can start
from a defined status following a cold or
warm restart of the control system (e.g.
assigning specific values to signals).
Cyclic processing Constantly repeated signal processing
(e.g. logic operations on binary signals,
reading in and analyzing analog values,
specifying binary signals for output,
outputting analog values).
Time-controlled
processing Special, time-dependent processing with the following time conditions:
- faster than the average cycle,
- at a time interval greater than the
average cycle time,
- at a specified point in time.
Interrupt-driven processing Special, fast reactions to certain process
signals.
Error reaction Handling problems within the normal
sequence of the program.
The Programs in a CPU
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Structure
Storing the user program After programming the user program, you must load it in the user
memory of the CPU 948 (directly from the PG) or via a memory card
whose contents are copied to the user memory by an OVERALL
RESET of the CPU.
Interfaces to the
system program
Organization blocks are available as interfaces to the system program
for the special types of processing.
User memory
Code blocks
Data blocks
Organization
blocks
OB
DB
DX
PB FB/FX SB
FB 8
SEGMENT 1
NAME :TRANS
0005 :L IB 3
0006 :T FW 200
0007 :C DB 5
0008 :DO FW 200
0009 :L DW 0
000A :T QW 6
000B :BE
1: KH = 0101;
2: KF = +120;
3: KS = xy;
4: KY = 4.5;
5: KG =
6: KM =
7:
1: KH = FFFF;
2: KH = FFFF;
3: KH = FFFF;
4: KH = FFFF;
5: KH = FFFF;
6: KH = FFFF;
7:
STEP 5
operations
static or dynamic data
(bits, bytes, words, double words)
static or dynamic data
(bits, bytes, words, double words)
STEP 5
operations STEP 5
operations STEP 5
operations
Program
blocks Function
blocks Sequence
blocks
&
&=
1
I1.5
I1.6
I1.4
I1.3 Q3.1
=
1
F 50.1
F 50.2
F 50.3 Q5.3
F1.7
I2.6 S
RQ
I1.3
User program
Fig. 1-2 Structure of a STEP 5 user program
The Programs in a CPU
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1.4 Which Operands are available to the User Program?
The CPU 948 provides the following operand areas for programming:
•• process image and I/Os
•• flags (F flags and S flags)
•• timers/counters
•• data blocks
Process image of the inputs
and outputs PII/PIQ
Characteristics Size
The user program can access the following data types
in the process image extremely quickly:
- single bits,
- bytes,
- words,
- double words
128 bytes
each for
inputs and
outputs
I/O area (P area)
Characteristics Size
The user program can access the I/O modules directly
via the S5 bus.
The following data types are possible:
- bytes,
- words.
256 bytes
each for
inputs and
outputs
Extended I/O area (O area)
Characteristics Size
The user program can access the I/O modules directly
via the S5 bus.
The following data types are possible:
- bytes,
- words.
256 bytes
each for
inputs and
outputs
Which Operands are available to the User Program?
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F flags
Characteristics Size
The flag area is a memory area which the user
program can access extremely quickly with certain
operations.
The flag area should be used ideally for working data
required often.
The following data types can be accessed:
- single bits,
- bytes,
- words,
- double words.
Single flag bytes can be used as interprocessor
communication flags (IPC flags) to exchange data
between the CPUs in the multiprocessor mode (refer
to Chapter 10). IPC flags are updated by the system
program at the end of the cycle via a buffer in the
coordinator or CP/IP.
2048 bits
S flags (extended flag area)
Characteristics Size
The CPU 948 also contains an additional flag area, the
S flag area. The user program can also access this area
extremely quickly as with the F flags.
S flags cannot however by used as actual operands
with function block calls nor as IPC flags for data
exchange between the CPUs. The bit test operations of
the CPU 948 can also not be used with the S flags.
These flags can only be used with the PG system
software "S5-DOS" from version 3.0 upwards or
"S5-DOS/MT" from version 1.0 upwards.
32 768 bits
Which Operands are available to the User Program?
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