Siemens S7-1200 PROFIBUS User manual

SIMATIC CM 1242-5
SIMATIC NET
S7-1200 - PROFIBUS
SIMATIC CM 1242
-5
Operating Instructions
01/2023
C79000
-G8976-C245-06
Preface
Application and properties
1
Displays and connectors
2
Installation, connecting up,
commissioning
3
Configuration and program
blocks
4
Diagnostics and upkeep
5
Technical data
6
Dimension drawings
A
Approvals
B
References
C

Siemens AG
Digital Industries
Postfach 48 48
90026 NÜRNBERG
GERMANY
C79000-G8976-C245-06
Ⓟ
01/2023 Subject to change
Copyright © Siemens AG 2011 - 2023.
All rights reserved
Legal information
Warning notice system
This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent
damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert
symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are
graded according to the degree of danger.
DANGER
indicates that death or severe personal injury will result if proper precautions are not taken.
WARNING
indicates that death or severe personal injury may result if proper precautions are not taken.
CAUTION
indicates that minor personal injury can result if proper precautions are not taken.
NOTICE
indicates that property damage can result if proper precautions are not taken.
If more than one degree of danger is present, the warning notice representing the highest degree of danger will
be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to
property damage.
Qualified Personnel
The product/system described in this documentation may be operated only by personnel qualified for the specific
task in accordance with the relevant documentation, in particular its warning notices and safety instructions.
Qualified personnel are those who, based on their training and experience, are capable of identifying risks and
avoiding potential hazards when working with these products/systems.
Proper use of Siemens products
Note the following:
WARNING
Siemens products may only be used for the applications described in the catalog and in the relevant technical
documentation. If products and components from other manufacturers are used, these must be recommended
or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and
maintenance are required to ensure that the products operate safely and without any problems. The permissible
ambient conditions must be complied with. The information in the relevant documentation must be observed.
Trademarks
All names identified by ® are registered trademarks of Siemens AG. The remaining trademarks in this publication
may be trademarks whose use by third parties for their own purposes could violate the rights of the owner.
Disclaimer of Liability
We have reviewed the contents of this publication to ensure consistency with the hardware and software
described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the
information in this publication is reviewed regularly and any necessary corrections are included in subsequent
editions.

SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 3
Preface
Validity of this manual
This document contains information on the following product:
CM 1242-5
Article number 6GK7 242-5DX30-0XE0
Hardware version 1
Firmware version V1.0.6
Communications module for connection of the SIMATIC S7-1200 to PROFIBUS (DP slave
module)
Figure 1 CM 1242-5
At the top right behind the hinged cover of the module housing, you will see the hardware
product version printed as a placeholder "X" (for example X 2 3 4). In this case, "X" would be
the placeholder for hardware product version 1.
Product name
In this document, the term "CM" is also used instead of the full product name "CM 1242-5".

Preface
SIMATIC CM 1242-5
4Operating Instructions, 01/2023, C79000-G8976-C245-06
New in this edition
•New firmware version with the following new functions, among others, compared to the
versions V1.0.4 and V1.0.5:
–Changing the PROFIBUS address from the user program using the data record 8193,
see:
Link: (https://support.industry.siemens.com/cs/ww/en/view/81522429)
–Small functional improvements
•New approvals (CCC / UKEX)
•Editorial revision
Replaced manual edition
Edition 02/2014
Current manual edition on the Internet
You can find the current version of this manual on the Internet pages of Siemens Industry
Online Support:
Link: (https://support.industry.siemens.com/cs/ww/en/ps/15667/man)
Purpose of the manual
This manual describes the properties of this module and supports you when installing and
commissioning the device.
The necessary configuration steps are described in the form of an overview.
You will find instructions for operation and maintenance and information on the diagnostics
options of the device.
Required experience
To install, commission and operate the CM, you require experience in the following areas:
•Automation engineering
•Setting up the SIMATIC S7-1200 system
•SIMATIC STEP 7
•Data transfer with PROFIBUS
Notes on this document
Product names
•CM / module / device
In this document, these terms are used instead of the complete product designation
CP 1243-1.

Preface
SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 5
Cross-references in the PDF
In this manual, there are often cross-references to other sections. To be able to return to the
initial page after jumping to a cross-reference, some PDF readers support the command
<Alt>+<left arrow>.
Search
To show all places where a term was found in a list, some PDF readers support the command
<Ctrl>+<Shift>+<F>.
Security information
Siemens provides products and solutions with industrial security functions that support the
secure operation of plants, systems, machines and networks.
In order to protect plants, systems, machines and networks against cyber threats, it is
necessary to implement – and continuously maintain – a holistic, state-of-the-art industrial
security concept. Siemens’ products and solutions constitute one element of such a concept.
Customers are responsible for preventing unauthorized access to their plants, systems,
machines and networks. Such systems, machines and components should only be connected
to an enterprise network or the internet if and to the extent such a connection is necessary
and only when appropriate security measures (e.g. firewalls and/or network segmentation)
are in place.
For additional information on industrial security measures that may be implemented, please
visit
Link: (https://www.siemens.com/industrialsecurity)
Siemens’ products and solutions undergo continuous development to make them more
secure. Siemens strongly recommends that product updates are applied as soon as they are
available and that the latest product versions are used. Use of product versions that are no
longer supported, and failure to apply the latest updates may increase customers’ exposure to
cyber threats.
To stay informed about product updates, subscribe to the Siemens Industrial Security RSS
Feed under
Link: (https://www.siemens.com/cert)
Observe the following security recommendations to prevent unauthorized access to the
system.
•Evaluate your plant as a whole in terms of security. Use a cell protection concept with
suitable products.
•Keep the firmware up to date. Check regularly for security updates of the firmware and
use them.
•Restrict physical access to the device to qualified personnel.
•Configure a protection level of the CPU.

Preface
SIMATIC CM 1242-5
6Operating Instructions, 01/2023, C79000-G8976-C245-06
Note on firmware/software support
Check regularly for new firmware/software versions or security updates and apply them. After
the release of a new version, previous versions are no longer supported and are not
maintained.
Device defective
If a fault develops, please send the device to your Siemens representative for repair. Repairs
on-site are not possible.
Decommissioning
Shut down the device properly to prevent unauthorized persons from accessing confidential
data in the device memory.
To do this, restore the factory settings on the device.
You achieve this by resetting the CPU using the online functions of STEP 7.
Recycling and disposal
The product is low in pollutants, can be recycled and meets the requirements of the WEEE
directive 2012/19/EU "Waste Electrical and Electronic Equipment".
Do not dispose of the product at public disposal sites. For environmentally friendly recycling
and the disposal of your old device contact a certified disposal company for electronic scrap
or your Siemens contact.
Keep to the local regulations.
You will find information on returning the product on the Internet pages of Siemens Industry
Online Support:
Link: (https://support.industry.siemens.com/cs/ww/en/view/109479891)
SIMATIC NET glossary
The SIMATIC NET glossary describes terms that may be used in this document.
You will find the SIMATIC NET glossary in the Siemens Industry Online Support at the
following address:
Link: (https://support.industry.siemens.com/cs/ww/en/view/50305045)
Training, Service & Support
You will find information on Training, Service & Support in the multi--language document
"DC_support_99.pdf" on the data medium supplied with the documentation.

SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 7
Table of contents
Preface ................................................................................................................................................... 3
1 Application and properties .................................................................................................................... 9
1.1 Connecting the S7-1200 to PROFIBUS .................................................................................. 9
1.2 Communications services of the CM..................................................................................... 9
1.3 Performance data .............................................................................................................. 10
1.4 Requirements for operation ............................................................................................... 10
1.5 Configuration examples for PROFIBUS ................................................................................ 11
2 Displays and connectors...................................................................................................................... 13
2.1 Opening the covers of the housing..................................................................................... 13
2.2 LEDs .................................................................................................................................. 14
2.3 Electrical connections ........................................................................................................ 16
3 Installation, connecting up, commissioning ....................................................................................... 17
3.1 Important notes on using the device .................................................................................. 17
3.1.1 Notices on use in hazardous areas...................................................................................... 17
3.1.2 Notes on use in hazardous areas according to ATEX / UKEX / IECEx / CCC-Ex ........................ 17
3.1.3 Notes on use in hazardous areas according to UL HazLoc and FM........................................ 18
3.2 Installation, removal and repairs in hazardous areas ........................................................... 19
3.3 Installing, connecting and commissioning.......................................................................... 20
3.4 Note on operation ............................................................................................................. 24
3.5 Disassembly....................................................................................................................... 25
4 Configuration and program blocks...................................................................................................... 27
4.1 Configuration .................................................................................................................... 27
4.2 DP data exchange with the CPU.......................................................................................... 28
4.3 New slave address with data record 0x2001....................................................................... 28
5 Diagnostics and upkeep ...................................................................................................................... 31
5.1 Diagnostics........................................................................................................................ 31
5.1.1 Diagnostics options............................................................................................................ 31
5.1.2 DP slave diagnostics........................................................................................................... 32
5.1.3 Standard diagnostics.......................................................................................................... 33
5.1.4 Device-specific diagnostics in DP-V1................................................................................... 35
5.1.5 Device-specific diagnostics in DP-V0................................................................................... 38
5.2 Maintenance ..................................................................................................................... 39
5.2.1 Downloading firmware ...................................................................................................... 39
5.2.2 Module replacement.......................................................................................................... 40

Table of contents
SIMATIC CM 1242-5
8Operating Instructions, 01/2023, C79000-G8976-C245-06
6 Technical data ..................................................................................................................................... 41
6.1 Technical specifications of the CM 1242-5.......................................................................... 41
6.2 Pinout of the D-sub socket ................................................................................................. 42
A Dimension drawings............................................................................................................................ 43
B Approvals............................................................................................................................................. 45
C References ........................................................................................................................................... 51
Index.................................................................................................................................................... 53

SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 9
Application and properties
1
1.1 Connecting the S7-1200 to PROFIBUS
Connecting the S7-1200 to PROFIBUS DP
The S7-1200 can be connected to a PROFIBUS fieldbus system with the following
communications modules:
•CM 1242-5
Operates as DP slave
•CM 1243-5
Operates as DP master class 1
If a CM 1242-5 and a CM 1243-5 are installed together, an S7-1200 can perform the
following tasks simultaneously:
•Slave of a higher-level DP master system
and
•Master of a lower-level DP master system
1.2 Communications services of the CM
Bus protocol
PROFIBUS communication with the S7-1200 CMs is based on the PROFIBUS DP-V1 protocol.
The supported functions are described below.
When configuring in third-party systems with the GSD file, the CM 1242-5 can also be
operated as a DP-V0 slave, refer to section Configuration (Page 27).
Possible DP masters for the DP slave CM 1242-5
With the DP slave module CM 1242-5, the S7-1200 can communicate with the following
DP-V0/V1 masters:
•SIMATIC S7-1200, S7-300, S7-400, S7-Modular Embedded Controller
•DP master modules and the distributed IO SIMATIC ET200
•SIMATIC PC stations
•SIMATIC NET IE/PB Link PN IO
•Programmable controllers of various vendors

Application and properties
1.3 Performance data
SIMATIC CM 1242-5
10 Operating Instructions, 01/2023, C79000-G8976-C245-06
Types of communication with the CM 1242-5 in DP-V1
The following types of communication are available with DP-V1:
•Cyclic communication
The CM supports cyclic communication for the transfer of process data between DP slave
and DP master.
Cyclic communication is handled by the operating system of the CPU. No software blocks
are required for this. The I/O data is read or written directly from/to the process image of
the CPU.
Reading out identification data
With data record 255 (index 65000 to 65003), according to the DP-V1 specification, the
identification data I&M 0 can be read out.
You will find information on the data structure in the PROFIBUS Profile Guideline, Part 1,
V1.1.1, order number 3.502.
1.3 Performance data
Number of CPs/CMs that can be plugged in per S7-1200 station
You can configure a maximum of three CMs/CPs per station, in other words, 3 DP slave
modules (CM 1242-5).
Transmission speeds of the CM 1242-5
As the transmission speed on PROFIBUS, values of 9.6 kbps to 12 Mbps are permitted for the
CM.
Characteristic data of the DP interface of the CM 1242-5
Maximum size of the DP data areas of the DP slaves
•Input area per DP slave: Max. 240 bytes
•Output area per DP slave: Max. 240 bytes
1.4 Requirements for operation
Configuration tool
To configure the CM, the following configuration tool is required:
STEP 7 Basic as of version V11 SP2 Update 2

Application and properties
1.5 Configuration examples for PROFIBUS
SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 11
CPUs of the S7-1200
Using the full functionalities requires a CPU as of firmware version 3.0.
1.5 Configuration examples for PROFIBUS
Below, you will find examples of configurations in which the CM 1242-5 is used as a DP slave
and the CM 1243-5 is used as a DP master.
Figure 1-1 Configuration example with a CM 1242-5 as PROFIBUS slave
Figure 1-2 Configuration example with a CM 1243-5 as PROFIBUS master

Application and properties
1.5 Configuration examples for PROFIBUS
SIMATIC CM 1242-5
12 Operating Instructions, 01/2023, C79000-G8976-C245-06

SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 13
Displays and connectors
2
2.1 Opening the covers of the housing
Location of the display elements and the electrical connectors
The LEDs for the detailed display of the module statuses are located behind the upper cover
of the module housing.
The PROFIBUS connector is located behind the lower cover of the module.
Opening the covers of the housing
Open the upper or lower cover of the housing by pulling it down or up as shown in the
illustration. The covers extend beyond the housing to give you a grip.
Figure 2-1 Opening the covers of the housing

Displays and connectors
2.2 LEDs
SIMATIC CM 1242-5
14 Operating Instructions, 01/2023, C79000-G8976-C245-06
2.2 LEDs
LEDs of the module
The module has various LEDs for displaying the status:
•LED on the front panel
The "DIAG" LED that is always visible shows the basic statuses of the module.
Table 2- 1 LED on the front panel
LED / colors
Name
Meaning
red / green
DIAG
Display of the basic status of the module
•LEDs below the upper cover of the housing
Open the upper housing cover. The LEDs here provide more detailed information on the
module status.
Table 2- 2 LEDs below the upper cover of the housing
LED / colors
Name
Meaning
yellow / green
RUN/STOP
Details on the operational and communications status of the
module
red
ERROR
Group error
- not used -
-
- not used -
-
Note
LED colors when the module starts up
When the module starts up, all its LEDs are lit for a short time. Multicolored LEDs display a
color mixture. At this point in time, the color of the LEDs is not clear.
Display of the operating and communication status
The LED symbols in the following tables have the following significance:
Table 2- 3 Meaning of the LED symbols
Symbol
-
LED status
OFF
ON (steady light)
Flashing, one color
Flashing yellow-
green
Not relevant

Displays and connectors
2.2 LEDs
SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 15
The LEDs indicate the operating and communications status of the module according to the
following scheme:
Table 2- 4 Display of the basic states of the module by the "DIAG" LED
DIAG
(red / green)
Meaning Comment
Power OFF
green
RUN without errors
flashing green
•Startup
•STOP without errors
•No project data
•Firmware update
The individual states are signaled by the
RUN/STOP and ERROR LEDs (see below).
flashing red
Problem / error The individual states are signaled by the
RUN/STOP and ERROR LEDs (see below).
Table 2- 5 Display schemes for detailed module statuses
DIAG
(red / green)
-
RUN/STOP
(yellow /
green)
ERROR
(red)
Meaning
Detailed status schemes
green
RUN without errors,
Exchange of user data with DP master
flashing green
•Stopped (STOP) without errors
•No project data available
flashing green
Starting up (STOP →RUN)
flashing green
Loading firmware
(The DIAG and RUN/STOP LEDs flash alternately.)
flashing red
- If a master-slave connection is established:
•DP master CPU in STOP, "CLEAR" on PROFIBUS
or
•Slave error

Displays and connectors
2.3 Electrical connections
SIMATIC CM 1242-5
16 Operating Instructions, 01/2023, C79000-G8976-C245-06
DIAG
(red / green)
- RUN/STOP
(yellow /
green)
ERROR
(red)
Meaning
flashing red
No master-slave connection detected.
red
PROFIBUS cable not connected or not detected.
In STOP mode, configuring and performing diagnostics on the CM remain possible.
2.3 Electrical connections
Power supply
The CM 1242-5 is supplied with power from the backplane bus. It does not require a separate
power supply.
9-pin D-sub female connector (PROFIBUS)
The PROFIBUS connector is located behind the lower cover of the module. The interface is a
9-pin D-sub female connector operating according to the RS-485 standard.
You also have the option of connecting to optical PROFIBUS networks via an Optical Bus
Terminal OBT or an Optical Link Module OLM.
You will find the pin assignment of the D-sub socket in section Pinout of the D-sub socket
(Page 42).
More detailed information on the electrical connections
For technical information on the electrical connections, refer to the section Technical data
(Page 41).

SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 17
Installation, connecting up, commissioning
3
Safety notices on the use of the device
Note the following safety notices when setting up and operating the device and during all
associated work such as installation, connecting up or replacing the device.
3.1 Important notes on using the device
3.1.1 Notices on use in hazardous areas
WARNING
The device may only be operated in an environment with pollution degree 1 or 2 as
described in EN/IEC 60664-1, GB/T 16935.1.
WARNING
EXPLOSION HAZARD
You may only connect or disconnect cables carrying electricity when the power supply is
switched off or when the device is in an area without inflammable gas concentrations.
3.1.2 Notes on use in hazardous areas according to ATEX / UKEX / IECEx / CCC-Ex
WARNING
Requirements for the cabinet
To comply with EU Directive 2014/34 EU (ATEX 114), UK Regulation SI 2016/1107 or the
conditions of IECEx or CCC-Ex, the housing or cabinet must meet the requirements of at
least IP54 (according to EN/IEC 60529, GB/T 4208) in compliance with EN IEC/IEC 60079-7,
GB 3836.8.

Installation, connecting up, commissioning
3.1 Important notes on using the device
SIMATIC CM 1242-5
18 Operating Instructions, 01/2023, C79000-G8976-C245-06
WARNING
Suitable cables at high ambient temperatures in hazardous area
Use heat-resistant cables with an ambient temperature ≥60 °C; these cables must be rated
for an ambient temperature that is at least 20 °C higher. The cable entries used on the
housing must comply with the IP degree of protection required by EN IEC 60079-0 /
GB 3836.1.
WARNING
Transient overvoltages
Take measures to prevent transient overvoltages of more than 40% of the rated voltage (or
more than 119 V). This is the case if you only operate devices with SELV (safety extra-low
voltage).
3.1.3 Notes on use in hazardous areas according to UL HazLoc and FM
This equipment is suitable for use in Class I, Division 2, Groups A, B, C and D or non-
hazardous locations only.
This equipment is suitable for use in Class I, Zone 2, Group IIC or non-hazardous locations
only.
WARNING
When used in hazardous environments corresponding to Class I, Division 2 or Class I, Zone
2, the device must be installed in a cabinet or a suitable enclosure.
WARNING
If the device is installed in a cabinet, the inner temperature of the cabinet corresponds to
the ambient temperature of the device.
WARNING
EXPLOSION HAZARD
The equipment is intended to be installed within an ultimate enclosure. The inner service
temperature of the enclosure corresponds to the ambient temperature of the module. Use
installation wiring connections with admitted maximum operating temperature of at least
30 ºC higher than maximum ambient temperature.

Installation, connecting up, commissioning
3.2 Installation, removal and repairs in hazardous areas
SIMATIC CM 1242-5
Operating Instructions, 01/2023, C79000-G8976-C245-06 19
3.2 Installation, removal and repairs in hazardous areas
WARNING
Impermissible accessories and spare parts
Risk of explosion in hazardous areas
•Only use original accessories and original spare parts.
•Observe all relevant installation and safety instructions described in the manuals for the
device or supplied with the accessories or spare parts.
WARNING
Unsuitable cables or connectors
Risk of explosion in hazardous areas
•Only use connectors that meet the requirements of the relevant type of protection.
•If necessary, tighten the connector screw connections, device fastening screws,
grounding screws, etc. according to the specified torques.
•Close unused cable openings for electrical connections.
•Check the cables for a tight fit after installation.
WARNING
Improper installation of shielded cables
There is a risk of explosion due to equalizing currents between the hazardous area and the
non-hazardous area.
•Ground shielded cables that cross hazardous areas at one end only.
•Lay a potential equalization conductor when grounding at both ends.
WARNING
Lack of equipotential bonding
If there is no equipotential bonding in hazardous areas, there is a risk of explosion due to
equalizing current or ignition sparks.
•Ensure that equipotential bonding is available for the device.
WARNING
Unprotected cable ends
There is a risk of explosion due to unprotected cable ends in hazardous areas.
•Protect unused cable ends according to IEC/EN 60079-14.

Installation, connecting up, commissioning
3.3 Installing, connecting and commissioning
SIMATIC CM 1242-5
20 Operating Instructions, 01/2023, C79000-G8976-C245-06
WARNING
Insufficient isolation of intrinsically safe and non-intrinsically safe circuits
Risk of explosion in hazardous areas
•When connecting intrinsically safe and non-intrinsically safe circuits, ensure that the
galvanic isolation is performed properly in compliance with local regulations (e.g. IEC
60079-14).
•Observe the device approvals applicable for your country.
WARNING
Unauthorized repair of devices in explosion-proof design
Risk of explosion in hazardous areas
•Repair work may only be performed by personnel authorized by Siemens.
3.3 Installing, connecting and commissioning
NOTICE
Improper mounting
Improper mounting may damage the device or impair its operation.
•Before mounting the device, always ensure that there is no visible damage to the device.
•Mount the device using suitable tools. Observe the information in the respective section
about mounting.
WARNING
Open equipment
The devices are "open equipment" acc. to the standard IEC 61010-2-201 or UL 61010-2-201
/ CSA C22.2 No. 61010-2-201. To fulfill requirements for safe operation with regard to
mechanical stability, flame retardation, stability, and protection against contact, the
following alternative types of installation are specified:
•Installation in a suitable cabinet.
•Installation in a suitable enclosure.
•Installation in a suitably equipped, enclosed control room.