Siemens SIMATIC S7 Equipment Manual
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Siemens SIMATIC S7 Equipment Manual

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

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Summary of Contents for Siemens SIMATIC S7

  • Page 1 SIMATIC S7 SM 338 Ultrasonic Position Encoding Module Equipment Manual Release 06/96...
  • Page 3 Contents Product Overview The SM 338 Module SIMATIC S7 Mounting Data Communication with the SM 338 Ultrasonic Position Encoding Operation Module Appendix Equipment Manual 762 21 087 Release 06/96...
  • Page 4 SIMATICR is a registered trademark of SIEMENS AG. Safety 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...

  • Page 5: Table Of Contents

    Table of Contents Product Overview ............The SM 338 Module .
  • Page 6 Table of Contents Figures Front view of the module ......... Principle of ultrasonic position encoding .
  • Page 7 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...
  • Page 8 Preface Working on In order to protect the modules from static electrical discharge, operating switching cabinets personnel must discharge themselves of static electricity before opening switching cabinets or switchboxes. Updated technical In contrast to the specifications contained in the ”General Technical Specifi- specifications cations”...

  • Page 9: Product Overview

    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.
  • Page 10 Product Overview 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.

  • Page 11: The Sm 338 Module

    The SM 338 Module SM 338 Equipment Manual (4) J31069-D401-U1-A0-7618...

  • Page 12: Layout

    The SM 338 Module Layout The SM 338 is installed in a compact, plastic housing. This housing is mounted on the rail of your programmable controller. The back The two plug connectors on the back connect the module to the P bus. The front All other connection and indicator elements are located on the front of the module.

  • Page 13: Led Indicators

    The SM 338 Module LED indicators The LED indicators on the front of the module have the functions listed in table 2-1. Table 2-1 LED indicators Indicator Function DC (green) External voltage present External voltage not present SF (red) System error/module requires diagnosis Normal operation SM 338 Equipment Manual (4) J31069-D401-U1-A0-7618...

  • Page 14: Measuring Principle

    The SM 338 Module Measuring Principle A START pulse is sent by the SM 338 via the RS 422 interface. The sensor electronics send an echo of this pulse back to the SM 338. The START pulse generates a current pulse in the sensor electronics. This current pulse moves from the sensor electronics toward the end of the measuring bar.

  • Page 15: Recommended Sensors

    The SM 338 Module Ultrasonic Measuring System System scope A system for ultrasonic position encoding includes the following: - - S7-300 PLC with CPU and power supply - - Ultrasonic positioning module SM 338 - - External supply voltage of 24 V - - Ultrasonic position encoding sensor(s) Sensor capabilities Ultrasonic position encoding sensors with the following capabilities can be...

  • Page 16: Possible Assignment Of The Measuring Points

    The SM 338 Module Allocation of the Except for the restrictions mentioned above, the measuring points can be al- measuring points located to the sensors as desired (e.g., 4-2-1-1, 2-2-2-2, 1-0-4-3, and so on). Figure 2-3 shows a complete system and a possible assignment of the mea- suring points.
  • Page 17 Installation SM 338 Equipment Manual (4) J31069-D401-U1-A0-7618...

  • Page 18: Mounting

    Installation Mounting Introduction The S7-300 is a programmable controller which can be equipped with vari- ous modules to meet the requirements of the particular automation task. Certain rules apply when positioning the SM 338 on the rail of the S7-300. A maximum of 8 signal modules may be placed to the right next to the CPU.

  • Page 19: Installation

    Installation Mounting the To mount the module on the rail, proceed as shown below. module 3. Switch CPU to STOP status. 4. Unscrew the screw on the bottom of the module to the left of the SM 338. 5. Swing this module up, and insert the included bus connector. Bus connector SM 338 Equipment Manual (4) J31069-D401-U1-A0-7618...

  • Page 20: Slot Numbers For S7 Modules

    Installation 6. Hook in (1) the SM 338 on the top of the rail, and swing down (2). 7. Tighten both modules with screws (turning moment for screwdriver: 80 to 110 Ncm). 8. Assign the SM 338 a slot number as shown in table 3-2. Table 3-2 Slot numbers for S7 modules Slot Number...

  • Page 21: Terminal Assignment

    Installation 9. Punch out the appropriate number on the front. Connecting exter- To connect the external supply voltage, open the covering flap on the left nal supply voltage side of the module. Table 3-3 Terminal assignment Terminal Assignment P24 (input voltage jumpered with 3) M24 (ground externally jumpered with 4) P24 (jumpered with 1) M24 (jumpered with 2)
  • Page 22 Installation Wiring For notes on installing an automation system, see the section on wiring an S7-300 in the S7-300 manual. For detailed information, see also the guidelines on interference-proof setup of programmable controllers. Order no: EWA 4NEB 811 617001 Use the following to connect the sensors. - - Connectors with shield spring (V42254-A1115-C325) - - Connector covers with shielding (V42254-A6000-Gx25) The sensor lines are shielded (6AP5 400-2AA01).

  • Page 23: Data Communication With The Plc

    Data Communication with the PLC Introduction The SM 338 is not equipped with operator control components. Software handles the complete configuration of the module. The housing does not need to be opened, and jumpers do not have to be inserted. Data communica- Data communication with the CPU of the PLC takes place in the dual port tion with the PLC...

  • Page 24: Input Area

    Data Communication with the PLC Input Area Organization The acquired counting values are stored in the input area. Each of the eight counters is represented with a resolution of 16 bits. Table 4-1 shows the or- ganization of the input area. Table 4-1 Input area Value of...

  • Page 25: Parameter Area

    Data Communication with the PLC Parameter Area General The parameters required for presetting the SM 338 are stored in two data re- cords in the 16-byte parameter area. This area can only be write-accessed by the P bus. The data can also be modified during running operation (i.e., dy- namically).
  • Page 26 Data Communication with the PLC Wire break monitoring These bits can be used to enable/disable wire break monitoring for each posi- tion sensor. Wire break monitoring is performed indirectly by evaluating the reaction of the position sensor to a START pulse from the SM 338. If the position sensor does not react within a specified period of time, this is considered a wire break.

  • Page 27: Example Of The Measuring Points Of A Sensor

    Data Communication with the PLC Sensor-related Two bytes each are used to assign the eight counters to the four sensors and counter assign- to specify their measuring points. ment Table 4-2 shows the applicable bytes for each sensor. Table 4-2 Bytes for counter assignment Sensor Number Bytes...
  • Page 28 Data Communication with the PLC Sensor-related The assigned counters for each sensor are set in one byte. counter setting Table 4-3 shows the respective byte assigned. Table 4-3 Bytes for setting the counters Sensor Number Byte Byte (n+2) Measuring cycle time 0 0 0 0 0 16.0 msec 0 0 0 0 1...
  • Page 29 Data Communication with the PLC Cycle time The SM 338 can generate an end-of-cycle alarm (i.e., process alarm 0) at the end of the cycle time set. This requires that generation be enabled in byte 1 of data record 0. Byte 14 Cycle time 0 0 0 0 0...

  • Page 30: Default Values For The Parameter Area

    Data Communication with the PLC Default settings Following a new start or a RESET of the module, the parameter area is set with the default values specified in table 4-4. Table 4-4 Default values for the parameter area Value Meaning Data record 0 Byte 0 No diagnostics and wire break monitoring...
  • Page 31 Data Communication with the PLC Diagnosis Area General The errors detected by the SM 338 are stored in the 12-byte diagnosis area. A set bit signals an error. If the error is a sporadic one, it is stored and re- ported to the CPU as “arriving”.

  • Page 32: System Diagnosis Bytes

    Data Communication with the PLC 4.3.1 System Diagnosis Bytes Note The contents of the system diagnosis bytes are standardized, and fixed desig- nations are used. The standardized term “channel” corresponds to a sensor for the SM 338. The system diagnosis bytes occupy the first 4 bytes of the diagnosis area. They contain errors occurring at the module level.
  • Page 33 Data Communication with the PLC Data communica- tion, program run Byte 2 time and supply Communication malfunction voltage (detected by the module) Time monitoring (Watchdog has triggered a RESET.) Failure of internal module supply voltage (sensor supply +15 V/+24 V; inter- face supply 5 V) Time monitoring The module is equipped with a time monitoring function to check that the...
  • Page 34 Data Communication with the PLC 4.3.2 Channel-Related Diagnosis Bytes Channel-related data are stored in bytes 4 to 11. The contents of bytes 4 to 6 are fixed while bytes 7 to 11 contain the actual channel errors. Channel type Byte 4 Channel type = 7E Diagnosis bits per channel...
  • Page 35 Data Communication with the PLC Individual errors of Byte 8: Channel 1 the channels Byte 9: Channel 2 Byte 10: Channel 3 Byte 11: Channel 4 Parameter error Wire break Pulse error Counter overflow Parameter error The channel (i.e., sensor) contains invalid parameters. Wire break The sensor has not supplied a STOP pulse.
  • Page 36 Data Communication with the PLC SM 338 Equipment Manual 4-14 (4) J31069-D401-U1-A0-7618...

  • Page 37: Operation

    Operation The parameters of the SM 338 must be assigned before it can begin position encoding. When an error occurs, it provides a diagnosis if this was enabled in the parameter assignment. SM 338 Equipment Manual (4) J31069-D401-U1-A0-7618...

  • Page 38: Parameter Assignment

    Operation Parameter Assignment Parameter assignment sets the SM 338 module to the connected sensors. There are three ways to assign parameters to the SM 338. Automatic parameter assignment Parameter assignment by the CPU during startup (SDB 100) Parameter assignment via SFC during operation Transferred parameters are always subject to a plausibility check.
  • Page 39 Operation Parameter assign- Parameter assignment via SFC (abbreviation of System Function Call) is per- ment via SFC formed during normal operation. All parameters in data records 0 and 1 can be changed. Note All parameters in both data records must always be valid since all 16 bytes are transferred and compared.

  • Page 40: Example Of An Sdb 100

    Operation Example of an SDB 100 Introduction Using a programmable controller containing an SDB 100, modules whose parameters can be assigned can be parameterized each time a switch is made from STOP to RUN. During startup, the CPU performs a bus identification procedure and enters the module identifier(s).
  • Page 41 Operation SDB 100 Program SDB 100 (* Slot directory = contents directory *) KH = 0008 (* Length of directory: The value corresponds to the number of entries (1 entry = 2 bytes) KH = 0000 (* Data offset in bytes for slot 4 *) KH = 0000 (* Data offset in bytes for slot 5 *) KH = 0012...
  • Page 42 Operation (* Infos (header) for data record 1 *) KH = 8014 (* Offset for net data, data record 1 in bytes *) KH = 010E (* Identifier for data record 1; length: 14 bytes *) KH = 0000 (* Reserved *) (* Parameters of the module *) KH = FF44 (* Channel diagnostics;...

  • Page 43: Normal Operation

    Operation Normal Operation After the parameters have been assigned correctly, the SM 338 functions in normal operation. This is signaled by the LEDs as shown below. DC (green) on SF (red) off Depending on the parameter assignment, the measured values of a sensor are updated synchronously (i.e., at the end of the cycle time) or asynchronously (i.e., at the end of the measuring cycle time).

  • Page 44: Error Diagnostics

    Operation Error Diagnostics Diagnostics acquire errors on the module Diagnostics Diagnosis information is updated continuously and stored in the diagnosis area of the dual port RAM. If channel-related diagnostics is enabled, this additional information is entered when channel errors occur. Both arriving and departing errors are considered by the diagnostics.

  • Page 45: Flowchart Of Channel-Related Diagnostics

    Operation Flowchart of chan- Channel-related diagnostics is performed as shown in the flowchart below. nel-related diag- nostics Parameter Diagnosis area area Error on channel x? “SF” LED on Entry in byte 7 Channel- (channel error related diagnostics Wire break? vector), and and monitoring en- bytes 8 to 11? abled?
  • Page 46 Operation SM 338 Equipment Manual 5-10 (4) J31069-D401-U1-A0-7618...

  • Page 47: Appendix

    Appendix SM 338 Equipment Manual (4) J31069-D401-U1-A0-7618...
  • Page 48 Appendix Technical Specifications Housing Supply Voltage for the Module Dimensions (in mm) 80 x 125 x 120 Internal From S7-300 bus Current consumption 80 mA (typical) Weight 500 g 100 mA (maximum) Protection class IP20 External 24 V Permissible voltage 20.4 to 28.8 V range Position Sensors...
  • Page 49 Appendix Electromagnetic Compatibility Electrostatic discharge 8 kV discharge via air In acc. with DIN 6 kV discharge via contact VDE 0843, part 2 (IEC 801-2) (Degree 3) High-energy, single pulse Additional measures re- quired In acc. with DIN Ex: Lighting cond. KT VDE 0839, part 10 (IEC 801-5) Type AD24V SIMATIC...
  • Page 50 Appendix Plug Connector Allocation Connection Plug connector X1 sensors 1 and 3 Sub D plug connector, 25-way socket Function -15 V voltage supply (with fuse/floating) Reference potential, voltage supply +15 V voltage supply (with fuse/floating) Sensor 1: STOP input (RS 422) Sensor 1: START output (RS 422) Sensor 3: STOP input (RS 422) Sensor 3: START output (RS 422)
  • Page 51 Appendix Connection Plug connector X2 sensors 2 and 4 Sub D plug connector, 25-way socket Function -15 V voltage supply (with fuse/floating) Reference potential, voltage supply +15 V voltage supply (with fuse/floating) Sensor 2: STOP input (RS 422) Sensor 2: START output (RS 422) Sensor 4: STOP input (RS 422) Sensor 4: START output (RS 422) Reference potential, voltage supply...
  • Page 52 V42254-A6209-L1 pebble gray Contact cover V42254-A6108-L1 Knurled screw V42254-A112-V109 black (10 each) V42254-A112-V009 kieselgrau (10 each) See data book on plug connectors from Siemens (order no. A23001-G21-D005) for minimum ordering quantities and packaging units. Lines Designation Order No. Sensor line...

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