Siemens SIMATIC S7 Technical Document

Ultrasonic Position Encoding Module
SM 338
SIMATIC S7
Release 06/96Equipment Manual

Contents
Product Overview 1
The SM 338 Module 2
Mounting 3
Data Communication with the
PLC 4
Operation 5
Appendix A
Release 06/96
SM 338
Ultrasonic Position Encoding
Module
Equipment Manual
762 21 087
SIMATIC S7

SM 338 Equipment Manual
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SIMATICRis a registered trademark of SIEMENS AG.
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:
!Danger
indicates that death, severe personal injury or substantial property damage will result if proper
precautions are not taken.
!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.
Note
draws your attention to particularly important information on the product, handling the product, or
to a particular part of the documentation.
The device/system may only be set up and operated in conjunction with this manual.
Note the following:
!Warning
This device and its components may only be used for the applications described in thecatalog or the
technical description, and only in connection with devices or componentsfrom other manufacturers
which have been approved or recommended by Siemens.
This product can only function correctly and safely if it is transported, stored, set up, and installed
correctly, and operated and maintained as recommended.
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 neces-
sary corrections included in subsequent editions. Suggestions for improvement are
welcomed.
Disclaimer of LiabilityCopyright ESiemens AG 1995 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.
Siemens AG
Automation Group
Systems Engineering
P. O. Box 2355
D-90713 Fuerth
Germany
Siemens Aktiengesellschaft Order No. 762 21 087
Technical data subject to change.
ESiemens AG 1995
Safety Guidelines
Qualified Personnel
Correct Usage

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SM 338 Equipment Manual
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Table of Contents
1 Product Overview 1-1......................................................
2 The SM 338 Module 2-1.....................................................
2.1 Layout 2-2.........................................................
2.2 Measuring Principle 2-4..............................................
2.3 US Measuring System 2-5...........................................
3 Mounting 3-1..............................................................
3.1 Installation 3-2.....................................................
3.2 Installation 3-6.....................................................
4 Data Communication with the PLC 4-1.......................................
4.1 Input Area 4-2......................................................
4.2 Parameter Area 4-3.................................................
4.3 Diagnosos Area 4-9.................................................
4.3.1 System Diagnosis Bytes 4-10.........................................
4.3.2 Channel--Related Diagnosis Bytes 4-12.................................
5 Operation 5-1..............................................................
5.1 Parameter Assignment 5-2...........................................
5.2 Example of an SDB 100 5-4..........................................
5.3 Normal Operation 5-7...............................................
5.4 Error Diagnostics 5-8................................................
6 Appendix A-1..............................................................
A.1 Technische Daten A-2...............................................
A.2 Plug Connector Allocation A-4........................................
A.3 Recommended Accessories A-6......................................

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Figures
2-1 Front view of the module 2-2.........................................
2-2 Principle of ultrasonic position encoding 2-4............................
2-3 Possible assignment of the measuring points 2-6........................
4-1 Organization of the dual port RAM 4-1.................................
4-2 Example of the measuring points of a sensor 4-5........................
5-1 Flowchart of channel--related diagnostics 5-9...........................
Tables
2-1 LED indicators 2-3..................................................
2-2 Recommended sensors 2-5..........................................
3-1 Slot for the SM 338 3-2..............................................
3-2 Slot numbers for S7 modules 3-4.....................................
3-3 Terminal assignment 3-5.............................................
4-1 Input area 4-2......................................................
4-2 Bytes for counter assignment 4-5.....................................
4-3 Bytes for setting of the counters 4-6...................................
4-4 Default values for the parameter area 4-8..............................
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SM 338 Equipment Manual
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Notes on the CE Seal
The following applies to the product described in this manual.
Products bearing the CE seal meet the requirements of EU Directive
89/336/EEC ’Electromagnetic Compatibility’ and the harmonized
European standards (EN) listed therein.
In accordance with article 10 of the above--mentioned EU Directive, the EU
declarations of conformity are held available for inspection by responsible
authorities at the addresses listed below:
Siemens Aktiengesellschaft
Bereich Automatisierungstechnik
AUT7 WKF KB2
Postfach 2355
D-90713 Fürth
The products have been designed for use in the industrial area and meet the
following requirements:
Area of Application Requirements
Emitted interference Immunity
Industry EN 50081-2 : 1993 EN 50082-2 : 1995
The products meet the requirements if you:
1. Observe the installation guidelines and safety notes contained in the ap-
plicable manuals and supplementary documentation, both for the pro-
grammable system and the individual module.
2. Observe the rules below.
The programmable systems and the listed modules must be installed in
grounded, closed metal enclosures (e.g., switching cabinets).
All signal lines outside this enclosure must be shielded as described in the
equipment manuals. The shields of the signal lines must be applied to the
shield bar at the entrance to the cabinet.
EU EMC directive
89/336/EEC
Area of application
Observing the
installation guide-
lines
Installing the
devices

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In order to protect the modules from static electrical discharge, operating
personnel must discharge themselves of static electricity before opening
switching cabinets or switchboxes.
In contrast to the specifications contained in the ”General Technical Specifi-
cations” of the manual, the specifications listed below on electromagnetic
compatibility apply to modules which carry the CE seal.
The specifications apply to devices installed in accordance with the stated
installation guidelines.
Electromagnetic Compatibility Specifications Test Values
Immunity to static electrical discharge1
Tested in accordance with EN 61000-4-2
Dischargetoair8kV
Discharge on contact
4kV
Immunity to electromagnetic fields1
STested in accordance with EN V 50140
(amplitude-modulated HF)
STested in accordance wit EN V 50204
((pulse--modulated HF)
80 to 1000 MHz
10 V/m
80% AM (1 kHz)
900 MHz
10 V/m
50% ED, 200 Hz
repetition frequency
Immunity to fast transient bursts
Tested in accordance with EN 61000-4-4
SSupply lines for AC 120/230 V
SSignal lines (I/O and bus lines)
2kV
2kV2
Immunity to high frequency
Tested in accordance with EN V 50141
0.15 to 80 MHz
10 V
80% AM (1 kHz)
Source impedance 150 Ω
Emitted interference1
Tested in accordance wit EN 55011
SEmission of electromagnetic fields
SEmitted interference over supply cable
Limit value class A,
group 1
Limit value class A,
group 1
1 For closed metal housing
2 Signal lines that are not used for process control: 1 kV (e.g., connections to external
printers)
Working on
switching cabinets
Updated technical
specifications
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SM 338 Equipment Manual
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Product Overview
The SM 338 is a position encoding module for the S7-300 programmable
controller. The module is connected to the P bus of the programmable con-
troller, and its parameters are assigned by the CPU. The SM 338 belongs to
the family of signal modules.
Position encoding is performed by ultrasonic sensors. These sensors offer the
following primary advantages.
SNo wear and tear
SHigh protection class
SSteady accuracy regardless of the sensor length
SLow costs for longer sensors (> 500 mm)
SUp to four measuring points (magnets) per sensor possible
SThe digital sensor interface (RS 422) is not sensitive to interference and
permits lines up to 50 m in length.
The SM 338 does not condition the data. Its only function is to supply the
CPU with counting values. Eight counters are available for the acquisition of
measured values.
Up to four sensors can be connected on the SM 338 module, and each sensor
can contain up to four measuring points. The sum of the measuring points on
all connected sensors may not exceed 8.
The sensors connected to the module can operate in synchronous or asyn-
chronous mode. This requires that the parameters of the selected sensors be
assigned appropriately.
Synchronous mode
The selected sensors operate synchronously (i.e., at the end of the cycle time,
the counting values of all synchronous sensors are transferred to the input
area of the dual port RAM). If enabled, an end-of-cycle alarm to the CPU is
then triggered. Synchronous mode does not use a parameterized, sensor-re-
lated, measuring cycle time.
Position encoding
with ultrasonic
sensors
Operating modes
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Asynchronous mode
The selected sensors operate asynchronously (i.e., each sensor operates with
its own specific sensor measuring cycle time). The measuring cycle time is
the time available to the sensor for one measurement. This time can be set
separately for each sensor. Cycle time and measuring cycle time are not de-
pendent on each other. At the end of the measuring cycle time, the counting
values allocated to this sensor are transferred to the input area of the dual
port RAM.
The SM 338 module is equipped with the following functions.
SEach sensor can be parameterized separately.
SCycle time and measuring cycle time can be parameterized separately
(and with different lengths).
SGlobal enabling of an end-of-cycle alarm (i.e., process alarm) can be
parameterized.
SGlobal enabling of diagnosis alarms can be parameterized.
SSensor-related enabling of the diagnoses can be parameterized.
SSensor-related enabling of wire break monitoring can be parameterized.
SFirmware monitoring via watchdog
SIndication of error states via two LEDs
SModule parameters can be reassigned during normal running operation.
The main application area of the SM 338 is with plastics processing ma-
chines. Particularly with injection molding and blow molding machines, ul-
trasonic sensors are being used increasingly for position encoding. The
SM 338 is the direct link from the sensor to the S7-300 programmable con-
troller.
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Functionality
Use
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