Siemens SIMATIC S7 Profibus DP

1 Introduction

This manual describes how the SIMATIC S7 PLC system is connected to the terminals in the Cimrex series via the fieldbus Profibus DP. Addressing of an item in the PLC system is done in the normal Siemens way. For information about the PLC system, refer to the manual for the current system.

The terminals support the systems in the SIMATIC S7 300 and 400 series.

The expansion card IFC PBDP must be installed in the terminal. See the IFC PBDP manual.

2 Install and update driver

When installing CIMREX PROG, the drivers available at the time of release are installed. A new driver can be added into CIMREX PROG either with CIMREX PROG using an Internet connection or from diskette. A driver can be updated to a newer version in the same ways.

2.1 Installation of driver using Internet

To update available drivers to the latest version or to install new drivers, use the function 'Update terminal drivers, from Internet' in the File menu in CIMREX PROG. All projects must be closed before this function is used, and the computer must have an Internet connection. A browser is not required. When the connection is established, a list is shown with all drivers that can be downloaded. The list shows the version number of available drivers and the version number of installed drivers. Mark the driver(s) you want to install. The function 'Mark Newer' will mark all drivers that are available in a newer version than the one installed and the drivers not installed. Then, select 'Download'. Each driver is approximately 500 KB and is ready to use when the download is complete.

2.2 Installation of driver from disk

To update available drivers to the latest version or to install new drivers, use the function 'Update terminal drivers, from Disk' in the File menu in CIMREX PROG. All projects must be closed before this function is used. Select the folder with the new driver and choose to open the .mpd file. A list is shown with all drivers that can be installed, showing the version number of available drivers and the version number of installed drivers. Mark the driver(s) you want to install. The function 'Mark Newer' will mark all drivers that are available in a newer version than the one installed and the drivers not installed. Then, select 'Install'.

How to select the SIMATIC S7 ProfibusDP driver in the project and how to transfer it to the terminal are described in chapter 3.

3 Connecting the terminal to the PLC system

3.1 Settings in the CIMREX PROG

For communication with SIMATIC S7 PLC system via the fieldbus Profibus DP, the following settings must be made in the programming tool CIMREX PROG.

Driver selection

Choosing 'New' in the File menu creates a new project and the dialog 'Project Settings' is shown. In an existing project, the dialog is shown by selecting 'Project Settings' in the File menu.

Project Settings Dialog:

• Terminal: CIMREX 70 2.0x [Change...]
• Controller system: SIMATIC S7-series (English) [Change...]
• Color scheme: [Current default] [Change...]

[OK] [Cancel]

Press 'Change...' under 'Controller system' to get the choice list of available drivers. Choose Brand name, Protocol, and Model, then press OK. Press OK again to confirm the project settings.

Select controller system Dialog:

• Brand name: FREQROL, GE Fanuc, IAI, idec, Koyo, MATSUSHITA, MELSERVO, MODICON, OMRON, PROSEC, SAIA, SIMATIC, Steeplechase
• Protocol: S5 3964R/RK512, S5 Profibus DP, S5 PG/AS511, S7 3964R/RK512, S7 200 PPI, S7 Profibus DP, S7 MPI (HMI adapter)
• Model: SIMATIC S7-series (English), SIMATIC S7-series (German)

[OK] [Cancel]

Communication setup

The settings for the communication between the terminal and the PLC system are done under 'Peripherals' in the Setup menu. Mark either slot 1 or slot 2, depending on which slot the expansion card IFC PBDP is installed in, and press 'Edit'. Select IFC PBDP and press OK.

Mark IFC PBDP in Peripherals and press Edit to state the settings for the HMI profile. State the size of the input and output area in bytes. Default settings is 32 bytes.

Peripheral configuration:

• RS-232C
• RS-422
• Loopback
• Expansion slots:
  • Slot 1: IFC PBDP, Controller: SIMATIC S7-series (English)
  • Slot 2: Unused functions, Printer, No protocol mode, CIMREX Tools, TCP/IP Connection 1, TCP/IP Connection 2, Modem

[Expand all] [Unused functions] [Collapse all] [Exit]

Driver configuration

Mark selected driver (SIMATIC S7-series) and press Edit to select Data format.

Driver configuration Dialog:

• Data format
• About
• Single DB access
• Multi DB access

[OK] [Avbryt] [Verkställ] [Hjälp]

Note! If Multi DB is supported, W#16#FFFF must be entered at db_address in the HMI profile. If Single DB is supported and you want to use another DB number than the predefined one (where DBnr=51 (hex 33)), a new DBno must be entered at db_address. See also separate description of the HMI profile.

Transfer the driver to the terminal

The selected driver is downloaded into the terminal when the project is transferred to the terminal. Choose 'Project' in the Transfer menu.

Project Transfer Dialog:

• Percent complete: 0%
• Byte count (Kb): 10
• Time elapsed:
• Status: [Send] [Receive] [Verify] [Stop]
• Info:
• Retries: 10
• Settings...
• Terminal Version:
• Test project on send
• Automatic terminal RUN/PROG switching
• Send complete project
• Check terminal version
• Partial send options:
  • Blocks: All, None, From: 0, To: 0
  • Delete
  • Trend data
  • Alarms
  • Symbols
  • Time channels
  • Message library
  • Setup
  • Function keys
  • Recipe Data
  • LED's
  • Passwords
  • Set terminal clock
• [Exit]

There are three alternatives when the driver is downloaded into the terminal:

3.2 Connecting the terminal to the Profibus DP network

With the expansion card IFC PBDP, the terminal can then be connected to a Profibus DP network as a slave. The PLC system in the network must be loaded with a program handling the communication between the terminal and the PLC system.

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3.3 Communication settings for the IFC PBDP card

IFC PBDP Card Connectors and LEDs:

• 1. Connector for the communication cable.
• 2. Bus termination: Set to ON on the first and last units in the network. The first unit in the network is often the master unit in the PLC system.
• 3. LEDs:
  • 1: Red, ERR: Configuration or communication error. The LED is red until the unit is configured. Indicates time out.
  • 2: Green, PWR: Power supply 5 VDC OK.
  • 3: Green, DIA: Diagnostic error, not used.
• 4. State the station number.

3.4 Cable to PROFIBUS-DP

Station 1

• RxD/TxD-P (3)
• DGND (5)
• RxD/TxD-N (8)
• Protective Ground
• Shield

Station 2

• ○ (3) RxD/TxD-P
• (5) DGND
• ○ (8) RxD/TxD-N
• Protective Ground

3.5 Technical data

The cable Unitronic-Bus L2/F.I.P is tested and has the following performance:

3.6 Description of the PLC program section

HMI-profile, with consistent data

Used for CPU types that support the data block SFC14 and SFC15. See information for respective type from Siemens. The PLC program section consists of three function blocks plus one block (OB1) that calls the function block 110.

Program block

The PLC program section, available on the type diskette, contains three function blocks, two system blocks, and one main program.

* SFC 14 and SFC 15 are not valid for all PLC types, see Siemens information for more detailed information.

Consistent data = whole messages are read and write in one scan.

Note! The following data types are used in the HMI profile: MW200-MW255, T99, which contains words, bytes, and bits.

The figure below shows how the "HMI profile" is placed in the PLC program.

PLC Program Diagram:

Application

"DPRD_DAT"
  EN
  ENO
  LADDR
  #RET_VAL_D
  RET_VAL_PRD
  P#DB112.DB
  RECORD
  X 0.0 BYTE
  32

  DB110
  FB110
    EN
    ENO
    Record_dp
    DW#16#0-rd
    Record_dp
    DW#16#20-wr
    W#16#70-Record_DB
    W#16#20 con_len
    db_address
    W#16#33 S
    db_flag_c
    W#16#6F-opy

"DPWR_DAT"
  EN
  ENO
  LADDR
  #RET_VAL_I
  RET_VAL_PWR
  P#DB112.DB
  X 32.0 BYTE
  32
  RECORD
[END]

The main program, OB1

OB1 is the main program where the parameters are defined for calling the other function blocks. The following parameters are defined for the FB110, SFC14 and SFC15:

For more information about the parameters, refer to the manual for SIMATIC S7.

Examples of configuration

In these examples, Siemens PLC system S7 and the PLC projects (HMI-conc) on the type diskette are used. The example describes the order in which to make the settings and connections to get the correct communication. GDS files and HMI profile (PLC project) are available also on the web.

SIMATIC S7 System Diagram

Diagram:

SIMATIC S7 --- PROFIBUS DP --- Terminal with the IFC PBDP card installed

Alternative 1: Current PLC project (HMI profile) for S7-315-2DP CPU

For procedure description, refer to the manual for handling S7-PLC and STEP7 from Siemens.

1. Install the terminal and IFC-PBDP according to the Installation manual delivered with the terminal.
2. Configure the terminal with the software package CIMREX PROG.
3. Copy the .GSD files from the diskette to the GSD-library in STEP7 (normally STEP7\S7data\Gsd\...).*
4. Update hardware library in STEP7 Hardware.
5. Copy the PLC project from the diskette to the computer (normally STEP7\S7proj\...).*
6. Start STEP7, open the PLC project.
7. Start Hardware STEP 7.
8. Check the hardware: CPU type, DP Master, E700 DP slave no. (Profibus DP\Additional Field Device\B+B\MAC-Exx0withIFC-P). Note! Station number for the IFC PBDP card must be the same as in the Hardware configuration.
9. Check DP slave properties:
   • I/O type: Input/Output
   • Address: for Input and Output area, default=64 in the HMI profile.
   • Length: for Input and Output area, default=32 in the HMI profile.
   • Unit: for Input and Output area=Byte.
   • Consistent via: Total Length.
10. Transfer the Hardware configuration to the S7 system.
11. Transfer the PLC program section to the S7 system. Note! If Multi DB is used, the DB address must be W#16#FFFF in FB110; single DB is default in the HMI profile.
12. Connect the cable between the S7 system and the IFC PBDP card in the terminal.
13. Put the S7 system and the terminal in run mode.

* GDS files and HMI profile (PLC project) are available also on the web.

Alternative 2: Complete, current or new PLC project together with HMI profile

For procedure description, refer to the manual for handling S7-PLC and STEP7 from Siemens.

1. Install the terminal and IFC-PBDP according to the Installation manual delivered with the terminal.
2. Configure the terminal with the software package CIMREX PROG.
3. Copy the .GSD files from the diskette to the GSD-library in STEP7 (normally STEP7\S7data\Gsd\...).*
4. Update hardware library in STEP7 Hardware.
5. Copy the PLC project from the diskette to the computer (normally STEP7\S7proj\...).*
6. Start STEP7, open the PLC project.
7. Start Hardware STEP 7.
8. Configure the hardware:
   • Select Rail, CPU type, DP Master, Exx0 DP slave no. (Profibus DP\Additional Field Device\B+B\MAC-Exx0 with IFC-P). Note! Station number for the IFC PBDP card must be the same as in the Hardware configuration.
9. Configure DP slave properties:
   • Select Universal Module to the IFC PBDP slave (drag and drop).
   • Select I/O type: Input/Output
   • State Address: for In- & Output area, default=64 in the HMI profile.
   • State Length: for In- & Output area, default=32 in the HMI profile.
   • Select Unit: for Input and Output area=Byte.
   • Select Consistent via: Total Length.
10. Transfer the Hardware configuration to the S7 system.
11. Open the PLC programs (block) for both projects (the new or current and the HMI profile project). Copy the blocks from the HMI profile project (OB1, FB110, FC111, FC112, DB51, DB110, DB111, DB112 SFC14 and SFC15). Note! If Multi DB is used, the DB address must be W#16#FFFF in FB110; single DB is default in the HMI profile. Check that the call in OB1 is correct defined.
12. Transfer the PLC program section to the S7 system (mark all blocks and select Download).
13. Connect the cable between the S7 system and the IFC PBDP card in the terminal.
14. Put the S7 system and the terminal in run mode.

* GDS files and HMI profile (PLC project) are available also on the web.

HMI profile without consistent data

Can be used by all CPU types, see information from Siemens. The PLC program section consists of three function blocks plus one block (OB1) that calls the function block 110.

Program block

The PLC program section, available on the type diskette, contains three function blocks and one main program.

The following figure shows how the HMI profile in OB1 is placed in the PLC program.

PLC Program Diagram:

Application

  DB110
  FB110
    EN
    ENO
    fb_in_off
    DW#16#40 set
    fb_out_of
    DW#16#40-fset
    W#16#20-con_len
    db_address
    W#16#33 S
    db_flag_c
    W#16#6Fopy
[END]

The main program, OB1

OB1 is the main program where the parameters are defined for calling the other function blocks. The following parameters are defined for the function block 110:

For more information about the parameters, refer to the manual for SIMATIC S7.

Examples of configurations

In these examples, Siemens PLC system S7 and the PLC program on the type diskette are used. The example describes the order in which to make the settings and connections to get the correct communication.

System Diagram:

SIMATIC S7 --- PROFIBUS DP --- Terminal with the IFC PBDP card installed

4 Addressing

The terminal can handle the following data types in the PLC system:

The project memory decides the max length of the DB (data block) in SIMATIC S7. The terminal can access all DB in the PLC system.

Note! If you try to access an undefined data block in the PLC-system, the PLC-system will stop.

All data types consist of byte areas. Addressing is always byte-specific, regardless of whether it is 1, 16, or 32 bits. The addresses are always decimal 0-65535.

For information about instructions in the PLC system, refer to the manual for the PLC system.

Digital signals

For digital signals, you state the current bit in the byte. For example, 150.3 means bit 3 in input byte 50.

* Multi DB
** Single DB
xxxx=address (minimum value = 0, depend, maximum value depend on the PLC-system) b=bit number 0-7. No = data block number (0-255).

Note! Writing bits from the terminal to the PLC is done in three steps:

1. Reading the whole byte from the PLC to the terminal.
2. The current bit is set/reset in the terminal.
3. Writing of the whole byte from the terminal to the PLC.

Analog signals

For 16-bit numbers, you state the suffix W; for example, MW100 means 2 bytes from memory byte 100-101.

* Multi DB
** Single DB
xxxx=address (minimum value = 0, depend, maximum value depend on the PLC-system) no=data block number (0-255) and adr=data word within the data base 0~8 kbyte (see current PLC type).

Note! When storing ASCII values in 16-bit numbers, the eight most significant bits contain the first ASCII code and the eight least significant bits contain the second ASCII code.

For 32-bit numbers, you state the suffix D; for example, MD100 means 4 bytes from memory byte 100-103.

* Multi DB
** Single DB
xxxx=address (minimum value = 0, depend, maximum value depend on the PLC-system), no=data block number 0-255 and adr=data word within the data base 0~8 kbyte (see current PLC type).

5 The HMI profile

This chapter describes the setup of the HMI profile and is for the benefit of readers who want to learn more about data exchange via the HMI profile.

The HMI profile allows exchange of an unlimited amount of data and also allows the terminal to access all types of devices in the PLC system. Together with the card, a type diskette is supplied containing PLC program for communication with different PLC systems.

PROFIBUS-DP allows a maximum byte length of 200 bytes in and 200 out per station. The HMI profile uses an input area and an output area. These areas are hereafter referred to as containers. The HMI uses the container to access the PLC.

For more detailed information on the HMI profile, see the specifications from the Profibus Organisation.

Diagram: HMI vs. PLC Data Exchange

HMI (DP slave) --- PROFIBUS DP --- PLC (DP master)

Request (from HMI to PLC)

Response (from PLC to HMI)

Containers

5.1 The data exchange

The terminal is a slave in the PROFIBUS-DP net. The PLC system is the master.

The terminal requests data from the PLC system through the input container.

The PLC program serves the terminal with data through the output container.

Handshaking between the terminal and the PLC system is performed through a Control byte in the containers.

The terminal can access all types of PLC devices.

When the terminal toggles the control byte, the PLC knows that the terminal wants to exchange data.

5.2 The request and response containers

The container starts at address 0 with the control byte. The control byte is used for handshaking and for communication failure detection. Addresses 1-3 are reserved for Fast bytes. These are not used in the terminal. Addresses 4 to 200 are used for communication. The terminal puts indexes here (3 bytes each) that refer to the PLC devices that the terminal wants to read or write. The PLC system, on the other hand, will put the data here from the PLC devices that the terminal has asked for. If the terminal wants to write to a PLC device, the data is stored immediately after the index.

Request container:

Response container:

The control byte in the request container:

The request container contains a message from the terminal to the PLC system.

Request

The request byte is used for handshaking between the units. The bit toggles when the terminal wants information for the PLC system.

COM

The COM bit is set by the terminal. If communication breaks, the bit will be reset.

The control byte in the response container

The response container contains the response from the PLC system to the HMI terminal.

Response

Is set to the same value as request when data is ready for transfer to the HMI terminal.

COM

The OM bit is set by the PLC program. If communication breaks, the bit will be reset.

Toggle

The toggle bit is always set to the same value as the toggle bit in the request container.

Error

This bit is not used.

Action

These bits are not used.

5.3 The index structure

The index is built up of 3 bytes. The index contains 4 parts of information:

• If the device should be read or written.
• Which type of device (input, data register, timer etc.)
• Number of device (e.g. input 5).
• Data length (from one bit up to 16 bytes).

PLC device type

States the type of PLC device according to the following table.

Ln0-Ln2

States the data length according to the following table.

Sequence of events

• The terminal decides which variables are to be read/written.
• The terminal toggles the request flag in the control byte.
• In the next PROFIBUS cycle, the PLC notices that the request flag has been changed.
• For each read index, the values of the requested devices are copied to the response container.
• Then the response flag in the response container is set to the same value as the request flag in the request container.
• In the next PROFIBUS cycle, the terminal notices that the request flag and the response flag are the same, which means that there is data for the terminal.
• The received values will now be used by the objects in the terminal.

6 Efficient communication

To make the communication between the terminal and the PLC system quick and efficient, the following should be noted about how the signals are read and what can be done to optimize the reading.

6.1 Signals affecting the communication time

It is only signals to objects in the current block that are read continuously. Signals to objects in other blocks are not read, meaning the number of blocks does not affect the communication time.

Besides the signals to objects in the current block, the terminal is continuously reading the following signals from the PLC system:

• Display signals
• Block print-out signals
• LED registers
• Alarm signals
• Remote acknowledge signals on alarms and alarm groups
• Login signal
• Logout signal
• Trend registers at the sample points
• Bargraph registers if using min/max indicators
• New display register
• Buzzer register
• Backlight signal
• Cursor control block
• Recipe control block
• Library index register
• Index registers
• PLC clock register if the PLC clock is used in the terminal
• List erase signal
• No protocol control register
• No protocol on signal

Signals not affecting the communication time

The following signals do not affect the communication time:

• Signals linked to function keys
• Time channels
• Objects in the alarm messages

6.2 How to make the communication more efficient

Group PLC signals consecutively

The signals from the PLC system are read most rapidly if all signals in the list above are consecutive. If, for example, 100 signals are defined, it is quickest to read these if they are linked to, for example, M0.0-M11.7. If the signals are spread out (e.g., I0.4, Q30.0, F45.3 etc.), the updating is slower.

Efficient block changes

Block changes are carried out most rapidly and efficiently through the block jump function on the function keys or through a jump object. "Display signals" in the block header should only be used when the PLC system is to force the presentation of another block. The "New Display" register can also be used if the PLC system is to change the block. This does not affect communication as much as a larger number of "Display signals".

Use the clock of the terminal

An extra load is put on communication if the clock of the PLC system is used, since the clock register must be read up to the terminal. Downloading of the clock to the PLC system also creates an extra load. The interval between downloadings should therefore be as long as possible.

Packaging of signals

When the signals are transferred between the terminal and the PLC system, all signals are not transferred simultaneously. Instead, they are divided into packages with a number of signals in each package. To decrease the number of packages that have to be transferred and make the communication faster, this number has to be considered. The number of signals in each package depends on the used driver. In the SIMATIC S7 Profibus DP driver, the number is 8 for analog devices and 128 for digital devices.

To make the communication as fast as possible, the number of packages has to be minimized. Consecutive signals require a minimum of used packages, but it is not always possible to have consecutive signals. In such cases, the so-called waste between two signals has to be considered. The waste is the maximum distance between two signals you can have and still keep them in the same package. The waste depends on the used driver. In the SIMATIC S7 Profibus DP driver, the number is 2 for analog devices and 24 for digital devices.

7 Appendix

7.1 Error messages

Error messages from the PLC system. The code is shown on the display of the terminal.