Instructions: All the information relevant to setting up a teleservice connection between an S7-200 controller and MD 720-3 as Remote Station of a local station based on the Micro Automation Sets 21 (Entry ID: 22537809) is available in the document provided here.
Note:
The SINAUT MD720-3 modem supports both GSM and GPRS communication. For GPRS communication, however, you also need the SINAUT MICRO SC software for the OPC server. For the use of teleservice only, you can also use the GSM modem SIPLUS TC65T (Entry ID: 26955813)
1. Introduction The following entry describes how you can synchronize the system time of a remote station with the central station.
A remote station, consisting of an S7-200 CPU and the SINAUT MD720-3 modem, is connected to a central station via GPRS (Fig. 01). SINAUT MICRO SC communicates with all configured remote stations on the central station.
With time synchronization, you should consider that SINAUT MICRO SC always transfers the UTC time of the PC. There is no automatic conversion into the local time zone of the remote station. This entry provides a function block that performs the conversion into the remote station's local time. There is also a description of how you must configure the remote station in order to execute real-time clock synchronization successfully.
Fig. 01: Block diagram
2. Configuring SINAUT MICRO SC Proceed as follows to activate the real-time clock transfer.
No.
Procedure (see Fig. 01)
1
Open SINAUT MICRO SC.
2
Mark the remote station.
3
Click on "Edit".
4
Select "Status monitoring via time synchronization"
5
Specify the time interval in which the SINAUT MICRO SC is to transfer the time (default: 15 minutes).
6
Then click on "OK".
Table 01: Configuring SINAUT MICRO SC
A time stamp is sent to the remote station every 15 minutes.
3. Configuring the remote station
3.1 Overview of time correction Fig. 02 illustrates the entire time synchronization process.
Fig. 02: Time synchronization with converted local time
3.2 Receiving the time synchronization telegram The block "WDC_RECEIVE" (Fig. 03) from the SINAUT MICRO SC library is responsible for receiving the time. Among other things, the block updates the 8-byte time buffer "NEWTIME" when a new time telegram is received by SINAUT MICRO SC. In this case, the output "NEWTIME_RECEIVED" is set to "1" for the duration of a cycle.
Fig. 03: "WDC_RECEIVE" block
The start address of the time buffer must be transferred as pointer. This can be seen when you look at the time buffer in the example with the start address &VB600 (table 01).
Byte
Description
VB600
Year (0-99)
VB601
Month (1-12)
VB602
Day (1-31)
VB603
Hour (0-23)
VB604
Minute (0-59)
VB605
Second (0-59)
VB606
Reserved - always at 0
VB607
Weekday (1-7) - 1 = Sunday, 2 = Monday and so on.
Table 02: Time buffer
Note:
Specifications in the time buffer are output in BCD format.
3.3 Calling the time conversion block If SINAUT MICRO SC sends a time telegram, this is stored in the specified time buffer. This time corresponds to the UTC time, irrespective of the local time zone. You have to convert it first if you want to use it for setting the S7-200 CPU real-time clock. The downloadable block "Time_Correct" (Fig. 04) handles the conversion. You integrate it into the user program as follows:
You call up the block when a new time is received. For this you use the output "NEWTIME_RECEIVED" of the "WDC_RECEIVE" block.
It accesses the time buffer specified under "NEWTIME". The hour correction value "Correct" is used to convert the time stored in the time buffer into the local time zone.
The converted time is written into the 8-byte address area that is addressed via the parameter "Corr_Time".
The following block parameters must be set on the "Time_Correct" block:
Parameter
Data size
Description
Correct
INT
Time difference of the CPU to the UTC time in whole hours (-12 to 12)
Recv_Time
8 bytes
Start address of the 8-byte time buffer specified in WDC_RECEIVE at the input "NEWTIME". The start address is transferred as pointer.
Corr_Time
8 bytes
Free start address of the 8-byte time buffer into which the converted time is copied. The start address is transferred as pointer.
Table 03: Block parameter "Time_Correct"
Fig. 04: "Time_Correct" block
3.4 Setting the real-time clock To set the CPU's real-time clock, you must call the "SET_RTC" block and specify the address area of the converted time (Fig. 05). You should likewise only call "SET_RTC" if a new time is received.
Fig. 05: "SET_RTC" block
4. Download: The download "time_correction.zip" contains the library "time_correction.mwl". The library was created with STEP 7 Micro/WIN V4.0.6.35.
Unpack the library into a directory of your choice.
Insert the library into your project. For information on inserting libraries see the S7-200 system manual in Entry ID: 1109582 .
Add the existing block to your program and parameterize it as described above.
1. Instructions The following entry describes which parameterization you have to make to the blocks in S7-200 program to be able to receive GPRS data from other stations.
Two or more remote stations, each consisting of a S7-200 CPU and the modem SINAUT MD720-3, are connected to a central station via GPRS. SINAUT MICRO SC administers communication with all configured remote stations on the central station (Fig.01).
Fig. 01: Block diagram
2. The blocks WDC_SEND and WDC_RECEIVE The blocks WDC_SEND and WDC_RECEIVE from the SINAUT MICRO SC library are responsible for sending and receiving data. Data receipt is signaled by the modem by flashing of the LED "C". If the parameters for the blocks are wrongly set, the data received is discarded and not written into the CPU. The following parameters are decisive for the data traffic:
WDC_SEND:
DATA_START: Start index of the first data byte, such as "100" for VB100
DATA_LENGTH: Length of data to be sent, such as "10" for 10 bytes
WDC_RECEIVE :
DATA_START: Start index of the data received (automatically updated on receipt of data)
DATA_LENGTH: Length of the data received (automatically updated on receipt of data)
RECVBUFFER_START and RECVBUFFER_LENGTH describe the receipt address area that may be overwritten with received data in the CPU.
The send address area DATA_START and DATA-LENGTH must fit into the receipt address area so that all the sent data of the receiving CPU is available.
3. Received data is discarded and not written into the CPU The examples listed below illustrate the problems with an incorrect parameterization of WDC_RECEIVE:
Fig. 02: No data is written in the CPU
Remote Station 1 sends data with a length of 10 bytes as of start index VB100
Remote Station 2 allows receipt of data with a length of 10 bytes as of VB200
The sent data is outside the address area approved by WDC_RECEIVE. The data is not written into the CPU. The send request is acknowledged with an error.
Fig. 03: No data is written in the CPU
Remote Station 1 sends data with a length of 20 bytes as of start index VB100
Remote Station 2 allows receipt of data with a length of 10 bytes as of VB100
Part of the sent data is outside the area approved by WDC_RECEIVE. The data is not written into the CPU. The send request is acknowledged with an error.
4. Received data is written correctly into the CPU The specified address area to WDC_RECEIVE must be at least as large as the send data address area.
4.1 Allowed area is an exact match
Fig. 04: The allowed address area is an exact match
Remote Station 1 sends data with a length of 10 bytes as of start index VB100
Remote Station 2 allows receipt of data with a length of 10 bytes as of VB100
The sent data is within the address area approved by WDC_RECEIVE. Beginning with VB100, 10 bytes are written into the CPU. The send request is acknowledged with "done".
4.2 Allowed area larger than received data
Fig. 05: The allowed address area is larger than the received data
Remote Station 1 sends data with a length of 10 bytes as of start index VB100
Remote Station 2 allows receipt of data with a length of 100 bytes as of VB50
The sent data is within the address area approved by WDC_RECEIVE. Beginning with VB100, 10 bytes are written into the CPU. The send request is acknowledged with "done".
Note: You can find further information on the topic of GPRS with SINAUT MICRO SC in the following system manuals:
"GPRS/GSM modem SINAUT MD720-3 System manual" Entry ID: 23117745
"SINAUT MICRO SC system manual" Entry ID: 23119827
Keywords: Communication, Data transfer
How can you prevent the PROVIDER from automatically disconnecting the GPRS connection between a MD720-3 modem and SINAUT MICRO SS?
Description: After the GPRS modem SINAUT MD720-3 has successfully established a connection to the SINAUT MICRO SC server, the connection is to be retained even if no data was sent or received for a long period (> 30 minutes). From the viewpoint of the mobile phone provider, this means that it has to provide communication bandwidth without earning any money from it. For this reason, it monitors the data traffic of every GPRS connection and ends the connection automatically if no data traffic was observed for a long period of time (time interval depends on the provider).
To counteract automatic disconnection of the GPRS connection by the mobile phone provider, the modem MD720-3 has various "watchdog" functions that generate a live telegram at certain time intervals. The time interval must be chosen so that it remains just under the monitoring time of the respective provider.
Instructions: Open SINAUT MICRO SC (Fig. 01)
Select the connection you would like to edit.
Click on "Edit".
Select one of the two following status monitoring functions.
Status monitoring by works update:
All configured tags of the OPC client are updated in the specified interval (for example, 15 minutes).
Status monitoring by time synchronization:
The current PC time (GMT time) is sent to the controller in the specified interval (for example, 15 minutes).
Click on OK.
Fig. 01: SINAUT MICRO SC settings
Note: You can find further information on the topic of GPRS with SINAUT MICRO SC in the following system manuals:
1. Instructions A remote station, consisting of an S7-200 CPU and the modem MD720-3, is to be connected with a SINAUT MICRO SC server via a GPRS connection. To parameterize the modem, it is necessary to define an IP address where the server can be reached in the INTERNET.
This entry describes how a remote station establishes a connection to a SINAUT MICRO SC server with a dynamic IP address.
Fig. 01: Introduction
2. Explanation of IP, host name and DNS To communicate with a PC in the Internet, you must know its IP address. The IP address is assigned to the PC by the appropriate provider during the logon to the INTERNET. It can be static, that means it is defined once and always remains the same. However, it can also be dynamic, meaning it changes regularly. A PC can be also be reached via its host name (such as "my_server.de"). For this, the allocated IP address must be assigned to the host name. The domain name system (DNS) performs this assignment. A DNS server then prepares this assignment list. The entry is automatically updated if the PC's IP address changes. The PC can still be reached under its host name. This procedure is also named DynDNS (dynamic domain name system).
The PC2 can either be reached via its current IP address (red path) or via its host name (blue path) from PC1. You can only reach it via its host name if it is assigned in the DNS server and the DNS server is known to the requesting system (Fig.02).
Fig. 02: IP, host name, DNS
3. The block WDC_INIT The block WDC_INIT (Fig.03) from the SINAUT MICRO SC library performs the initialization of the modem. It knows the parameters for establishing a GPRS connection and a connection to the server. Only the following parameters are described in this entry:
IP_ADDRESS_CS:
IP address or host name of the SINAUT MICRO SC server
DNS:
IP address of the DNS server(s) of the GPRS provider
Fig. 03: WDC_INIT:
4. Parameterizing the server address As explained above, there are two options for reaching a PC in the Internet. These two options are also available for parameterizing the modem.
4.1 Parameterization with IP address
If the SINAUT MICRO SC server has a static IP address, you perform the parameterization as follows:
IP_ADDRESS_CS:
IP address of the server (such as: "217.234.124.144")
DNS:
remains free (" ; ")
4.2 Parameterization with host name
If the SINAUT MICRO SC server has a dynamic IP address and can be reached via a host name, you perform the parameterization as follows:
IP_ADDRESS_CS:
Host name of the server (such as: "www.my-server.de")
DNS:
IP address of the DNS server of the GPRS provider (such as: "195.183.096.28;195.182.96.61")
You will find the IP address of the DNS server in the documentation for your GPRS provider. If you need to define two DNS servers, these must be separated by a semi-colon (;). ("DNS1;DNS2").
Important Note:
When parameterizing with host name, you must define a DNS server otherwise no connection can be established to the SINAUT MICRO SC Server. The SINAUT MICRO SC server also cannot be reached for the period in which it is receiving a new IP address and the update in the DNS server has not yet been executed.
Note: You can find further information on the topic of GPRS with SINAUT MICRO SC in the following system manuals:
System manual GPRS/GSM modem SINAUT MD720-3 Entry ID: 23117745
1. Introduction The connection between a modem and SINAUT MICRO SC is sometimes disrupted. Either the connection to SINAUT MICRO SC is not established or an existing connection is aborted. This entry describes how you can use SINAUT MICRO SC to diagnose connection failures.
2. SINAUT MICRO SC log file In the installation path of SINAUT MICRO SC (default: C:\Program Files\Siemens\SINAUT MICRO SC) there is the file "m2mopc.log". In this file, all connection requests and connection failures are written that are recorded by SINAUT MICRO SC. Each entry includes the following information:
Time stamp
Type of entry (info, error, warning)
Action (listen, send, recv, read, test connection)
Error description or additional information (modem name, IP address, reason for the entry)
3. Evaluation of the log file The log file can be opened and viewed with the standard editor. An evaluation is always worthwhile if
The modem does not register on the server, but a GSM (Q LED flashes) and GPRS connection (S LED flashes) of the modem exists
There are connection disruptions during running operation
3.1 How can you recognize that a connection has been successfully established or ended? A successfully-established connection consists of 3 related entries (register to SINAUT MICRO SC, transfer modem name and password, confirm login). If the modem logs off properly from SINAUT MICRO SC, this is likewise recorded.
Type of entry
Action
Text
Description
INFO
(list)
New Client on <IP address>
SINAUT MICRO SC receives the information that a modem wants to log in with the <IP address>
INFO
(recv)
<Modem name>
SINAUT MICRO SC receives the <Modem name>
INFO
(send)
login successful
SINAUT MICRO SC confirms the successful login to the modem
INFO
(read)
Session successfully closed
Connection successfully ended
3.2 How can you recognize when a connection has been unsuccessful/incorrect? The following log file entries give information about an unsuccessful attempt at establishing a connection between modem and SINAUT MICRO SC or about an incorrectly-established connection with the possibility of exchanging data.
Type of entry
Action
Text
Description
Possible cause / solution
INFO
(send)
wrong password
no connection established because the password in the modem does not match the password in SINAUT MICRO SC
Incorrect password entered / Check the password
INFO
(send)
username wrong
no connection established because the modem name in the modem does not match the modem name in SINAUT MICRO SC
Incorrect modem name entered / Check the modem name
WARNING
(OnDataReceived)
Wrong Sequence Number received
Connection is established, but data exchange is not possible because the station number in the modem does not match the station number in SINAUT MICRO SC
Incorrect station number entered / Check the station number
3.3 How can you recognize an aborted connection? The following log file gives information about an aborted connection between modem and SINAUT MICRO SC.
Type of entry
Action
Text
Description
WARNING
Test connection()
("modemname") Device not responding! Closing session.
SINAUT MICRO SC has sent data for status monitoring and received no answer from the modem. Connection was aborted
ERROR
Read()
("modemname") Reading on socket failed! Closing session.
SINAUT MICRO SC expects data from the modem. Data was not received or an incorrect data package was received. Connection was aborted
There are several possible causes for a connection abort. For diagnostics, check in the log file whether the modem dials in again after the connection is aborted and which address it has before and after the abort.
No.
Diagnostics
Possible causes
Possible solution
1.
A new login of the modem with a different IP address than for the login before the connection was aborted
Provider has interrupted the GPRS connection, modem had to log on to the GPRS network again
Check GPRS signal strength at modem location, if necessary contact provider or change provider
There was no data traffic between modem and SINAUT MICRO SC for a long period. Shorten interval of status monitoring in SINAUT MICRO SC
2.
A new login of the modem with the same IP address as for the login before the connection was aborted
There was a data collision between modem and CPU, the answer to SINAUT MICRO SC was not sent --> Timeout to SINAUT MICRO SC
Data package incorrect
Check GPRS provider and Internet provider. Contact provider and try another provider if the problem persists
Check your own IT infrastructure and connect SINAUT MICRO SC server directly to DSL router, to reduce the influence of network traffic
3.
No new dial-in of the modem
Modem defective or SINAUT MICRO SC has failed
Change modem
Important! The entries mentioned are example solution proposals. In practice, possible causes and solutions can vary.
Note: You can find further information on the topic of GPRS with SINAUT MICRO SC in the following system manuals:
System manual GPRS/GSM modem SINAUT MD720-3 Entry ID: 23117745
1. Introduction: The following describes how the change between GPRS mode and AT mode works for the SINAUT MD720-3 modem and how to change safely between the two modes.
A remote station, consisting of an S7-200 CPU and the SINAUT MD720-3 modem, is connected to a central station via GPRS (Fig. 01). SINAUT MICRO SC communicates with all configured remote stations on the central station.
Fig. 01: Block diagram
2. Basic functions of the WDC_CONTROL block: The block WDC_CONTROL (Fig. 02) from the SINAUT MICRO SC library modifies the communication mode (Freeport/PPI) of the interface between CPU and modem. It performs the change between GPRS and AT mode and Teleservice. The latter will not be dealt with in detail in this entry.
Essentially the following happens:
If the CPU goes into RUN, the interface between CPU and modem is switched into Freeport mode.
The modem sets up a GPRS connection.
If the connection was successfully set up, the remote station logs itself in at the central station.
In order to access the modem directly (e.g. to send a text message (SMS)) from the user program via AT-commands, the modem must be switched to the AT command mode. A positive edge at the input ACT_AT_MODE activates the modem's AT command mode.
There are two options for switching back into GPRS mode:
Via a positive edge to ACT_GPRS_MODE and by specifying a time delay to DELAY_TIME_GPRS.
Automatically after expiry of the time specified in MAX_TIME_AT
The block WDC_CONTROL confirms the switch process with Done, Aborted and Error. It continues to display which operating mode is active (INT_MODE). For a more detailed description, see the SINAUT MICRO SC system manual with the Entry ID: 23119827.
Fig. 02: WDC_CONTROL
3. Changing into AT mode If you want to change from GPRS mode to AT mode, setting ACT_AT="1" results in the following procedure:
WDC_CONTROL recognizes edge and switches to operating mode change (INT_MODE = 0)
WDC-CONTROL sends a change request to the modem
Modem confirms with OK
WDC_Control activates AT mode (INT_MODE = 3)
Fig. 03: Changing into AT mode
4. Communication disturbance during the change into AT mode:
The PC/PPI cable used between CPU and modem only prepares a half-duplex connection. Data reception to the CPU has priority here. Communications disturbances occur when you switch to AT mode during data reception (Fig. 04).
There are two distinct cases here.
Case 1: CPU and modem exchange data for initializing
Case 2: CPU receives GPRS data (e.g.: real-time synchronization)
If you want to change into AT mode and this leads to a communication disturbance through one of the two cases, this results in the following procedure: After setting ACT_AT = "1"
WDC_CONTROL recognizes edge and switches to operating mode change (INT_MODE = 0)
WDC-CONTROL sends a change request to the modem, the CPU simultaneously receives data from the modem
sending of the change request to the modem is disturbed
WDC_CONTROL does not receive an OK and goes into timeout
WDC_CONTROL does not switch into AT mode (INT_MODE = 0) and signals an error (ERROR = 1); a second attempt to change into AT mode does not take place
Fig. 05: Disturbed change procedure
5. Work around: A secure change from GPRS mode to AT mode can only take place if no data is being received by the CPU at the time of the change. The probability of a disturbed change is greatest during the initializing phase or if GPRS data is being received. To prevent a disturbance by the initializing phase, the modem has to be in GPRS mode for at least 30 seconds. Therefore use the following query before changing into AT mode:
an WDC_CONTROL you must have INT_MODE = "1" & DONE = "1" & BUSY = "0", before you can change into AT mode.
INT_MODE = "1" should last for at least 30 seconds
However, if WDC_CONTROL signals an error, proceed as follows:
No.
Procedure
Note
Result
1
If ERROR = "1", then repeat the edge to ACT_AT
You must run WDC_CONTROL for at least 1 cycle with ACT_AT = "0" before setting ACT_AT = "1".
WDC_CONTROL either changes to the AT mode or signals an error
2
If you get ERROR = "1" again, repeat the edge to ACT_AT two more times
WDC_CONTROL either changes to the AT mode or signals an error
3
If you still get an error after the third repeat, change via an edge to ACT_GPRS into the GPRS mode
You must run WDC_CONTROL for at least 1 cycle with ACT_AT = "0" before setting ACT_AT = "1".
WDC_CONTROL changes into the GPRS mode
4
Trigger the change into AT mode again following the above-mentioned query
WDC_CONTROL either changes to the AT mode or signals an error
Note: Find further information on the topic of GPRS with SINAUT MICRO SC in the following system manuals:
System manual GPRS/GSM modem SINAUT MD720-3 Entry ID: 23117745
Configuration Notes: Taking three examples we describe the settings required to set up a connection with the TS Adapter II modem to nodes on the network, like an S7-200.
In this sample configuration we will use:
TS Adapter II modem (order number: 6ES7 972-0CB35-0XA0)
S7-200 / CPU 224
S7-300 / CPU 315-DP
TP177B
No.
Example 1:
1
Connect TS Adapter II modem (TeleService Adapter II with integrated modem) directly with an S7-200 controller.
( 22 KB )
Fig. 01
If you connect a TS Adapter II modem directly to the interface of the S7-200 (e.g. CPU224) without any other active nodes on the network, e.g. a panel, then online communication with STEP 7 - Micro/WIN only works if the TS Adapter II modem is configured to the MPI*) or Advanced PPI*) network type. All other settings such as Auto and PROFIBUS lead to the display of "BUSF" on the TS Adapter.
*)Notes:
If you configure the MPI network type on the TS Adapter II modem, "PG/PC is the only master on the network" must be enabled on the TS Adapter.
Advanced PPI is to be set on the TS Adapter II when there are multiple CPU2xx on the MPI/PPI network and one or multiple CPU interfaces being operated in Master mode.
No.
Example 2:
1
Connect TS Adapter II modem (TeleService Adapter II with integrated modem) directly with an S7-200 controller and a panel via MPI.
( 30 KB )
Fig. 02
If you connect a TS Adapter II modem directly to the interface of the S7-200 (e.g. CPU224) and there are other active nodes on the network, e.g. a panel, then online communication with STEP 7 - Micro/WIN only works if the TS Adapter II modem is configured to the MPI network type.
With this setting it is possible to download a project to the panel with WinCC flexible. Furthermore, with this setting you can set up an online connection to the controller with Micro/WIN.
Note:
In some cases it might happen that the panel changes to Transfer mode when the communication interface is updated in MicroWIN
(MicroWIN > Communication > "Double-click for update").
2
Settings on the panel: On the panel you must enable "MPI Transfer" and "Remote Control" for Transfer settings
(Start menu > Control Panel > Transfer).
No.
Example 3:
1
Connect TS Adapter II modem (TeleService Adapter II with integrated modem) directly with an S7-200 controller, an S7-300 controller and a panel via MPI.
( 37 KB )
Fig. 02
If you connect a TS Adapter II modem directly to the interface of the S7-200 (e.g. CPU224) and there are other active nodes on the network, e.g. a panel, then online communication with STEP 7 - Micro/WIN only works if the TS Adapter II modem is configured to the MPI network type.
With this setting it is possible to download a project to the panel with WinCC flexible. Furthermore, with this setting you can set up an online connection to the controller with Micro/WIN.
Note:
In some cases it might happen that the panel changes to Transfer mode when the communication interface is updated in MicroWIN
(MicroWIN > Communication > "Double-click for update").
2
Settings on the panel: On the panel you must enable "MPI Transfer" and "Remote Control" for Transfer settings
(Start menu > Control Panel > Transfer).
Which country ID number is to be set for countries that are not supported by the EM241 modem module?
Configuration notes:
The application of the modem is not tested for countries that are not listed in Table 10-1 or A-47 of the S7-200 system manual (Entry ID 1109582). The EM241 includes an analog modem that is certified only for specific countries. The country ID number defines the telephone standard to which the modem must be set. It is possible that the EM241 might function in a country not listed with the country code of a country listed in the table with the same or similar telephone standard, but operation can be neither guaranteed nor supported.
Why can't you communicate with SCADA software (WinCC) using SIMATIC MicroComputing V1.0 and the EM241 modem module?
Description: MicroComputing V1.0 does not support
modem communication. However, S7-200 and WinCC do support the
MODBUS protocol.
SIMATIC MicroComputing offers access to the process data in the
S7-200 CPU and establishes the connection via ActiveX controls.
The EM241 modem module offers the "Remote communication"
function for the S7-200 micro PLC and supports the following four
operating mode:
Micro/Win connection for remote programming and
trouble-shooting,
MODBUS master/slave communication,
alphanumerical messages and number call service,
as well as CPU-CPU communication between S7-200
micro-controllers.
For further information, please refer to the FAQs on
"Possible ways of communicating with an S7-200 from WinCC
V5.1", which you can find on the Internet under Entry ID:
21382197.
Remedy: The HMI ‘WinCC’ software can be used as a
MODBUS master and the EM241 modem module can be used as a MODBUS
slave. Communication can be established this way between WinCC and
the S7-22x CPU module via a telephone line.
Keywords: Data transfer, Microcomputing, WinCC, Modem,
S7-200
How can you send an SMS text using an S7-200 and EM 241?
Description:
If you want to send an SMS via a landline network from a S7-200, you need the following components:
CPU S7-200
CPU 222 and CPU 224 starting with release 1.10
CPU 224XP
CPU 226 and CPU 226XM starting with release 1.00
Modem module EM 241
PG / PC with STEP 7 Micro / WIN starting with version 3.2.x
Analog telephone line
Configuring the modem module
In order to configure the modem module EM 241, open STEP 7 Micro / WIN and select the Modem Expansion Wizard.
Fig. 1: Selecting Modem Expansion Wizard
Select "Configure Modem module EM 241" and confirm with "Continue".
Please confirm the symbolic addressing with "Yes".
Enter the module position of the EM 241 or execute "Read module" while online. Click on "Continue".
Activate the password protection and enter a password or skip this step with "Continue".
Select "Activate PPI Protocol for modem module" and confirm with "Continue".
Select "Enable messages in this configuration" and click on "Configure message transmission".
In the next window, click on the tab "Text message" and go to "New message".
Enter your message in the text field and assign a symbolic address. If you want to enter additional data, go to "Add data". Define the appropriate values and confirm with "OK". Click on "Save message" to save this message.
Choose the tab "Phone Number Properties", to define the telephone numbers.
Go to "New Phone Number", enter the data and confirm with "Save".
Fig. 2: Phone Number Properties
Select the number in the left field and transfer it into the right field by clicking on the button "-->". Click on "OK".
Click on "Continue" and skip the next window with "Continue".
In this window, choose the number of dial attempts. Select the dial type "Tone" and select the field "Dial without activating tone". Confirm the entries with "Continue".
Go to "Suggest address" to select a free memory range and confirm with "Continue".
Choose the output byte according to your configuration and click on "Continue".
Confirm the display of the project components with "Close".
Finish the configuration.
In STEP 7 Micro / WIN, create the program link for the EM 241.
Fig. 3: Program link
Load the program into the CPU. SMS messages are sent out of the CPU if the enable and start bits are active.
Configuring the telephone numbers You can find the most recent data (as at 06/2008) for configuring the phone numbers of T-D1, D2 Vodafone, E Plus and other network-neutral accesses in the following table.
Changing or deleting passwords or source phone numbers
If you have saved a source phone number or a password in the properties of the phone number and would like to change or delete it, changing or deleting is not enough! The old password or the source phone number remains in the data module.
The password or the source phone number must be changed or deleted in the properties of the phone number. Then the phone number has to be deleted from the field "Phone numbers selected".
Fig. 4: Removing the phone number after changing the phone number properties
Then add the phone numbers again. This transfers the changed values to the data block and they are available as changed parameters for the phone number.
Fig. 5: Adding the phone number to apply the changed parameters
Troubleshooting The SMS may not be sent even though you have configured the system as described above. This can have several causes:
The phone number for the message transmission service has changed
Provider is overloaded
Recipient provider and the message transmission service provider are not compatible
For a possible remedy, proceed as follows:
Ask your provider if the named phone numbers for the message transmission service are still up to date.
Use the Data Logging of your S7-200 to obtain written confirmation of any provider overload at particular times. Evaluate the Data Logging and contact your provider. Information on Data Logging is available in Entry ID 21337731 and in the S7-200 system manual in Entry ID: 1109582
Try to send the SMS via another provider (alternatively: AnnyWay).
Make sure that the receiver provider and the message transmission service provider are compatible (D1 and D1, E Plus and E Plus). Most providers do not support sending an SMS to another provider. Since you can now change provider and keep your phone number, it is no longer possible to identify a provider clearly by the prefix of the phone number. You therefore need to get information on the receiver provider and change the phone number configuration as described above.
Further information Ask your provider if the named phone numbers for the message transmission service are still up to date.
Description:
The Modem Assistant in STEP 7-Micro/WIN 3.2.3.17 does generate a false bit in the output byte (Ax.7 instead of Ax.0). Thus, the modem module can only receive calls, however, it can not perform calls or send SMS. For this reason, the operations MODx_MSG und MODx_XFR do not work.
However, this behaviour does only occur, if the sub program has been created by the modem assistant in STEP 7-Micro/WIN 3.2.3.17 or in case, a sub program, resulting from a previous STEP 7-Micro/WIN Version, had been processed with this assistant.
Remedy: Verify the command bit "MODx_CmdBit" in the symbol table "MODx_SYM" - which is used by the assistant. X represents the location of the module. This bit should be called Ay.0 - y represents the output byte which is used by the module. In case, the bit is called Ay.7, please proceed according to the subsequent description:
Fig. 01
After each network that includes a call of modem wizard operation (MODx_CTRL, MODx_MSG and MODx_XFR) you add this network:
Network
LD MODx_CmdBit // x is the module position
=I Qy.0 // y is the output byte which the modem module uses
Fig. 02
Note: This behavior has been cleared in STEP 7-Micro/WIN 3.2 SP4 and higher.
Why isn't any connection to the controller set up when implementing the EM241 modem module in combination with STEP 7 - Micro / WIN version V3.2.4.27 and higher?
Description:
If you implement the EM241 modem module in combination with STEP 7 - Micro / WIN version V3.2.4.27 and higher for a connection to an S7-200, then you must pay attention to the settings of the transmission rate of the PC/PPI cable.
When implementing STEP 7 - Micro / WIN V3.2.4.27 and higher it is possible to set the baud rate to 187.5 kbit/s in the settings for the PC/PPI cable. However, the EM241 modem module does not support this baud rate.
Fig. 01
Therefore do not set the transmission rate of the PC/PPI cable to 187.5 kbit/s. If the incorrect transmission rate is set, you get the following message in the information window of the modem connection in STEP 7 - Micro/WIN: "Waiting for incoming messages..."
Fig. 02
Then STEP 7 - Micro/WIN waits without display of error messages and without continuation of the connection setup. You must abort the connection setup and check the settings in the Properties of the PC/PPI cable and correct them if necessary.
If the setting is correct, the modem connection is set up and you see the CPU that is connected to the remote modem (EM241).
Fig. 03
Note:
This behavior only occurs in combination with STEP 7 - Micro/WIN version V3.2.4.27 and higher and the EM241 modem module. Only this software version and higher supports the S7-200 RS 232/ PPI multi-master cable (6ES7 901-3CB30-0XA0).
With which SIMATIC S7-200 CPUs can you use the EM241 modem module?
Attachment 1: 
