Siemens S5-155U User Manual

SIMATIC S5

S5-155U

CPU 948

Programming Guide

Order No. 6ES5 998-3PR21

Release 03

Introduction

User Program

Program Execution

Operating Statuses and Program

Execution Levels

Interrupt and Error Diagnosis

Integrated Special Functions

Extended Data Block DX 0

Memory Assignment and

Memory Organization

Memory Access Using

Absolute Addresses

Multiprocessor Mode and

Communication in the S5-155U

PG Interfaces and

Functions

Appendix

Further Reading

List of Abbreviations,

List of Key Words,

List of Tables and Figures

The Pocket Guide CPU 922/CPU 928/CPU 928B/ CPU 948

Order No. 6ES5 997-3UA22 is included with this manual.

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C79000-H8576-C848-03

Copyright

Copyright © Siemens AG 1993 All Rights Reserved

The reproduction, transmission or use of this document or its contents is not permitted without express written authority.

Offenders will be liable for damages. All rights, including rights created by patent grant or registration of a utility model or design, are reserved.

Disclaimer of liability

We have checked the contents of this manual for agreement with the hardware and software described. Since deviations cannot be precluded entirely, we cannot guarantee full agreement. However, the data in this manual are reviewed regularly and any necessary corrections included in subsequent editions. Suggestions for improvement are welcomed.

Technical data subject to change.

Safety-related guidelines

This manual contains notices which you should observe to ensure your own personal safety, as well as to protect the product and connected equipment. These notices are highlighted in the manual by a warning triangle and are marked as follows according to the level of danger:

	!	Warning
		indicates that death, severe personal injury or substantial property damage can result
		if proper precautions are not taken.

	Caution
!	indicates that minor personal injury or property damage can result if proper
	precautions are not taken.

Only qualified personnel should be allowed to install and work on this equipment. Qualified persons are defined as persons who are authorized to commission, to ground and to tag equipment, systems and circuits in accordance with established safety practices and standards.

Siemens Aktiengesellschaft

6ES5 998-3PR21

EWK Elektronikwerk Karlsruhe

Printed in the Federal Republic of Germany

How to Use this Manual

Scope

This programming guide describes the following versions of the

CPU 948 and its system software:

Versions of the CPU 948

∙CPU 948-1 with 640 Kbytes of user memory, Order no. 6ES5 948-3UA11, from version A03

∙CPU 948-2 with 1 664 Kbytes of user memory, Order no. 6ES5 948-3UA21, from version A03

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How to Use this Manual

Overview of the Chapters

Chapter 1	This informs you about the areas of application of the S5-155U
	programmable controller with the CPU 948 and its device structure.
	It explains the typical mode of operation of the CPU and illustrates
	how a CPU program is structured.
	The chapter also contains suggestions about how to tackle
	programming and which characteristics of the CPU 948 are important
	for programming.
	If you have already worked with the CPU 946/947 and want to know
	the differences between these CPUs and the CPU 948 you will find
	this information in this chapter.

Chapter 2	This explains the components of a STEP 5 user program and how the
	program can be structured.

Chapter 3	This is intended for readers who do not yet have much experience of
	using the STEP 5 programming language. It therefore deals with the
	basics of STEP 5 programming and explains the STEP 5 operations in
	detail (with examples).
	Experienced readers who may find that the information about specific
	operations in the pocket guide is inadequate, can use Section 3.5 as a
	reference section.

Chapter 4	This provides an overview of the modes and program execution levels
	of the CPU 948. It provides you with detailed information about
	various start-up modes and the associated organization blocks in
	which you can program your routines for differrent start-up situations.
	The chapter also explains the differences between the program
	execution levels "cyclic processing", "time-controlled processing" and
	"interrupt-driven processing" and which blocks are available for your
	user program.

Chapter 5	This informs you about errors to be avoided when planning and
	writing your STEP 5 programs.
	The chapter tells you about the help you can obtain from the system
	program for diagnosing errors and which reactions can be expected
	and informs you about the blocks in which you can program reactions
	to certain errors.
	The chapter also explains the CPU 948 self-test.

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	How to Use this Manual
Chapter 6	This covers the special functions integrated in the system program. It
	tells you how to use the special functions and how to call and assign
	parameters to the special function OBs. The chapter also explains how
	to recognize and deal with errors in the processing of a special
	function.
Chapter 7	This describes the use of data block DX 0 and its structure. The
	chapter informs you of the significance of the various DX 0
	parameters. Based on examples, you will learn how to create data
	block DX 0 or how to assign the parameters in a screen form.
Chapter 8	This is a reference section for experienced system users. It provides
	information about the memory organization of the CPU 948 and
	certain system data words which contain information that can be
	called up by the user.
Chapter 9	This is also for experienced system users. The chapter explains how to
	address data in certain memory areas using absolute addresses.
Chapter 10	This explains when the multiprocessor mode can be used and how
	data can be exchanged between the CPUs and CPs. The chapter
	provides information about programming for multiprocessor operation.
	The remainder of the chapter provides detailed information and
	application examples for exchanging larger amounts of data in the
	multiprocessor mode (multiprocessor communication).
Chapter 11	This tells you how to connect your CPU to a PG and the functions
	provided by the PG software to test your STEP 5 program.
Chapter 12	This contains the Appendix with technical data (e.g. typical operation
	execution times, system runtimes, memory capacity) of the CPU 948.

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How to Use this Manual

Chapter 13 This lists documentation for further reading.

Chapter 14	This is intended to help you find themes quickly and contains a list of
	abbreviations and a list of keywords as well as lists of all the
	numbered tables and figures.

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How to Use this Manual

Conventions used in the text

	To provide you with an overview of the contents of the pages, the
	manual uses the following conventions in addition to a 2nd and 3rd
	order of titles:
Entries in the margin	Entries in the margin are keywords printed in italics on the left-hand
	edge of a page. They provide information about the contents of one or
	more paragraphs on the page.

Fourth order entries	Fourth order entries are not numbered but appear in the margin in bold
	face and identify a longer section of text.
	The following conventions are also used.

Notes

Note

Important information is indicated in this format.

Instructions	Instructions (often a sequence of operations to be performed) are
	represented in tables, e.g.
	Step	Action	Result
	1	Switch the mode selector	The CPU is in the stop
		from RUN to STOP.	mode. The STOP LED is lit
			continuously.
	2	Hold the reset switch in the	An OVERALL RESET is
		OVERALL RESET position;	requested. The STOP LED
		at the same time, switch the	flashes quickly.
		mode selector from STOP to
		RUN and back to STOP.

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How to Use this Manual

Reference tables	Specific information you may require at any time is contained in
	numbered tables as shown in the following example and can be found
	in the list of tables (refer to Chapter 14).

Table 3-2 Binary logic operations

Operation	Operand	Function
A		AND logic operation with scan for signal state "1"
O		OR logic operation with scan for signal state "1"
	I 0.0 to 127.7	of an input in the PII
	......	........

Examples	Examples, some of which cover several pages, are highlighted by a gray
	frame. When the examples cover more than one page this is clearly
	indicated.

Example 1: Calling and assigning parameters to a function block in the methods of representation STL and LAD/CSF in a program block

Method of representation STL

......

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Contents

Contents

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-6
1.3	The Programs in a CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-8
1.4	Which Operands are available to the User Program? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-12
1.5	How much Memory is available for the User Program? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-15
1.6	How to Tackle Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-16
1.7	Programming Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-19
1.8	What is New with the CPU 948? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-20
1.8.1	CPU 948, Version A01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-20
1.8.2	CPU 948, Version A02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-23
1.8.3	CPU 948, Version A03 and higher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1-23
1.9	Converting User Programs of the CPU 928B for the CPU 948. . . . . . . . . . . . . . . . . . . . . . . . . .	1-24
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
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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
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	Introduction and Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-4
4.2	Program Execution Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-7
4.3	STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-12
4.3.1	SOFT STOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-12
4.3.2	HARD STOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-16
4.3.3	OVERALL RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-17
4.4	START-UP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-19
4.4.1	MANUAL and AUTOMATIC COLD RESTART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-20
4.4.2	MANUAL and AUTOMATIC WARM RESTART. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-21
4.4.3	Comparison between COLD RESTART and WARM RESTART . . . . . . . . . . . . . . . . . . . . . . . .	4-24
4.4.4	RETENTIVE COLD RESTART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-25
4.4.5	Comparison of COLD RESTART and RETENTIVE COLD RESTART . . . . . . . . . . . . . . . . . .	4-26
4.4.6	User Interfaces for Start-Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-27
4.4.7	Extended AUTOMATIC WARM RESTART with the CPU 948 (HOT RESTART). . . . . . . . . .	4-30
4.4.8	Interruptions during START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-31
4.5	RUN Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-33
4.5.1	Cyclic Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-34
4.5.2	Specifying Time and Interrupt-Driven Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-36
4.5.3	Time-Controlled Program Execution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-37
4.5.4	Interrupt-Driven Program Execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4-45

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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
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 6.3 OB 122: "Disable Interrupts" On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11 6.4 OB 124: Delete STEP 5 Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13 6.5 OB 125: Generate STEP 5 Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 6.6 OB 126: Define, Transfer Process Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19 6.7 OB 129: Battery State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 6.8 OB 131: Delete ACCUs 1, 2, 3 and 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25 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

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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
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/RT Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8-15
8.3.5	Bit Assignment of the System Data Words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8-18
8.3.6	Addressable System Data Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8-42

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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
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

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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

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 IPCFlag 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11-26
11.5.1	Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11-26
11.5.2	How the PG Functions Work via the S5 Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11-28
11.5.3	Installation and Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11-30
11.5.4	Condition Codes Indicating Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11-34

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12 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3

Appendix 1: Jumper Settings for System Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 4

Appendix 2: Inserting and Removing the PG Submodule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 5

Appendix 3: Technical Data of the CPU 948, CPU 946/947 and CPU 928B. . . . . . . . . . . . . . . . . . . . 12 - 7

Appendix 4: Results IDs of some of the Special Function OBs in ACCU 1 . . . . . . . . . . . . . . . . . . . 12 - 10 Byte IDs in ACCU-1-LL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 10 Word IDs in ACCU-1-L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 12

13 Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 3

14 Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 1

List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 3

List of Key Words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14 - 5

List of Tables and Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 11

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 11

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 17

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Introduction	1

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 - 6
1.3	The Programs in a CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 8
	System program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 8
	User program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 10
1.4	Which Operands are available to the User Program? . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 12
1.5	How much Memory is available for the User Program? . . . . . . . . . . . . . . . . . . . . . . .	1 - 15
1.6	How to Tackle Programming? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 16
1.7	Programming Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 19
1.8	What is New with the CPU 948?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 20
1.8.1	CPU 948, Version A01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 20
1.8.2	CPU 948, Version A02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 23
1.8.3	CPU 948, Version A03 and Higher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1 - 23
1.9	Converting User Programs of the CPU 928B for the CPU 948 . . . . . . . . . . . . . . . . . .	1 - 24

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1

Introduction	1
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.

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Area of Application for the S5-155U with the CPU 948

1.1Area 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.

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Area of Application for the S5-155U with the CPU 948

Example of application

Fig. 1-1 illustrates the use of the S5-155U programmable controller in

a cement works.

1

PG 770	PG 770	PG 770	PG 770	PG 770
System management	Data base/	Quarry,	Coal mill,	Cement
	logging	Raw meal silo,	Kiln	mills,
		Crusher,		Dispatch
		Raw mill
Service system	Control room
				SINEC H1	bus

						PG	770
Process data control
Operation and monitoring (COROS)						Process
						data
						editing
S5-155U	S5-155U	S5-155U	S5-155U	S5-155U	S5-155U	S5-155U
Crusher,	Raw mill	Coal mill	Heat	Clinker cooler	Telephone	Cement mills
Test station,	Raw meal	Dryer	exchanger	Clinker transport	system	Distribution
Limestone	silos		Rotary	Dust collector	Central
store			kiln		control room

Fig. 1-1 Example of application of the S5-155U with the CPU 948

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1 - 5

Typical Mode of Operation of a CPU

1.2Typical Mode of Operation of a CPU

Mode of operation of a CPU The following modes of operation are possible in a CPU:

1.

2.

3.

Cyclic processing

Time-controlled processing

Interrupt-driven processing

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

CPU

Process

All the input modules assigned to the

1

CPU are scanned by the system

program and the values read in are

stored in the process image of the

Read in process image

Input I 1.3

inputs (PII).

Input I 1.4

of

the inputs

Input I 1.5

The values contained in the PII are

Evaluate input signals,

2

processed by the user program and the

set output signals

values to be output are entered in the

I 1.5

&

I 1.6

process image of the outputs (PIQ).

I 1.4

= 1

&

I 1.3

Q

3.1

The values contained in the process

Output Q 2.0

Output process image

3

image of the outputs are output by the

of

the outputs

Output Q 3.1

system program to the output modules

Output Q 4.7

assigned to the CPU.

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Typical Mode of Operation of a CPU

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.

1

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					The types of processing listed above are handled by the CPU
priority					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.

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The Programs in a CPU

1.3The Programs in a CPU

System program

Update process image of the inputs

Output process image of the outputs

Manage memory

The program existing on every CPU is divided into the following:

∙the system program

and

∙the user 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).

Execute start-up

System	Call
	user
program	processing
	(inter-
	faces)

Communication with	Handle errors
the PG

Fig. 1-2 Tasks of the system program

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The Programs in a CPU

Tasks

The tasks include the following: 1)

∙ cold and warm restart,

1

∙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.

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The Programs in a CPU

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.

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The Programs in a CPU

Structure

User memory

1

User program

		Code blocks
Organization		Program		Function			Sequence
blocks		blocks		blocks			blocks
	OB	PB		FB/FX				SB
	STEP 5	STEP 5		STEP 5			STEP 5
	operations	operations		operations			operations
I 1.5	&			FB 8				F 1.7
		F 50.1
							I 2.6	S
I 1.6		= 1		SEGMENT 1
	= 1
		F 50.2
				NAME	:TRANS
I 1.4	&
							I 1.3	R	Q
			Q 5.3
I 1.3		F 50.3		0005	:L	IB	3
		Q 3.1		0006	:T	FW 200
				0007	:C	DB	5
				0008	:DO	FW 200
				0009	:L	DW	0
				000A	:T	QW	6
				000B	:BE

Data blocks

DB			1:	KH = 0101;
static	or dynamic data		2:	KF = +120;
(bits,	bytes, words, double	words)	3:	KS = xy;
			4:	KY = 4.5;
			5:	KG =
			6:	KM =
			7:
DX			1:	KH = FFFF;
static	or dynamic data		2:	KH = FFFF;
		words)	3:	KH = FFFF;
(bits,	bytes, words, double		4:	KH = FFFF;
			5:	KH = FFFF;
			6:	KH = FFFF;
			7:

Fig. 1-3 Structure of a STEP 5 user program

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	Organization blocks are available as interfaces to the system program
system program	for the special types of processing.

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1 - 11

Which Operands are available to the User Program?

1.4Which 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		128 bytes
	in the process image extremely quickly:		each for
	-	single bits,	inputs and
	-	bytes,	outputs
	-	words,
	-	double words
I/O area (P area)
		Characteristics	Size
	The user program can access the I/O modules directly		256 bytes
	via the S5 bus.		each for
			inputs and
	The following data types are possible:		outputs
	-	bytes,
	-	words.
Extended I/O area (O area)
		Characteristics	Size
	The user program can access the I/O modules directly		256 bytes
	via the S5 bus.		each for
			inputs and
	The following data types are possible:		outputs
	-	bytes,
	-	words.

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Which Operands are available to the User Program?

F flags

		Characteristics	Size
					1
	The flag area is a memory area which the user		2048 bits
	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.

S flags (extended flag area)

Characteristics	Size
The CPU 948 also contains an additional flag area, the	32 768 bits
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.

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Which Operands are available to the User Program?

Timers (T)

Characteristics	Size
The user program loads timer cells with a time value	256 timer
between 10 ms and 9990 s and by means of a start	cells
operation, decrements the timer from this value at the
preselected intervals until it reaches the value zero.

Counters (C)

Characteristics	Size
The user program loads counter cells with a start value	256
(max. 999) and then increments or decrements them.	counters

Data words in the current data block

		Characteristics	Size
	A data block contains constants and/or variables in the		256
	byte, word or double word format. With STEP 5		words
	operations, you can always access the "current" data		1)
	block (refer to Section 2.4.2).
	The following data types can be accessed:
	-	single bits,
	-	bytes,
	-	words,
	-	double words.

1)In data blocks with a length greater than 256 words, you can only access data words with the numbers > 255 with operations for absolute memory access (refer to Chapter 9).

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How much Memory is available for the User Program?

1.5How much Memory is available for the User Program?

For storing logic and data blocks, the CPU 948 only has the user		1
memory in the internal RAM.
The CPU 948 is available with two versions of the user memory:
∙	Version 1: with 640 Kbytes,
∙	Version 2: with 1,664 Kbytes.

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How to Tackle Programming

1.6How to Tackle Programming

If you are an experienced user, you have probably found the most suitable method for creating programs for yourself and you can skip this section.

Less experienced readers will find tips for designing, programming, testing and starting up your STEP 5 program.

Implementation stages	The implementation of the STEP 5 control program can be divided
	into three stages:
	Stage	Activity
	1	Determining the technological task
	2	Designing the program
	3	Creating, testing and starting the program
Recursive procedure
	In practice, you will recognize that certain steps must be repeated
	(recursive procedure), e.g. when you realize that more signals are
	required to improve the handling of the task.

Stage 1	Determining the technological task:
	Stage	Activity

1Create a general block diagram outlining the control tasks of your process.

2Create a list of the input and output signals required for the task.

3Improve the block diagram by assigning the signals and any particular time conditions and/or counter statuses to the individual blocks.

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