Topic: CM635

Siemens S7-1200/1500 (Ethernet:ISO over TCP/IP) Addressing

 

Memory Type

Range

Description

Read/Write

Data Type

I

I

0.00 - 65535.7

Input Memory

R/W

Bit

IB

0 - 65536

Byte

IW

0 - 65535

Word

ID

0 - 65535

Double Word

Q

Q

0.00 - 65535.7

Output Memory

R/W

Bit

QB

0 - 65536

Byte

QW

0 - 65535

Word

QD

0 - 65535

Double Word

M

M

0.00 - 65535.7

Internal Memory

R/W

Bit

MB

0 - 65536

Byte

MW

0 - 65535

Word

MD

0 - 65535

Double Word

DB

DBX

1.0 - 65535.65535

Data Block

Memory

R/W

Bit

DBB

Byte

DBW

Word

DBD

Double Word

Note: Timers and Counters are System Blocks that are not addressable.

 

Note: Data_Blocks must have β€œOptimized Block Access” DISABLED in the Simatic Step 7 software.

Use the Offset column of the Data Block as the byte address for C-more. Even though the DB is defined as β€œInt” the offset is still byte not word.

Siemens Elementary Types

C-more Tag Data Type

Siemens Memory Types

BOOL

Discrete

I/Q/M/DBX

BYTE

Signed Int 16

IB/QB/MB/DBB

WORD

IW/QW/MW/DBW

INT

DWORD

Signed Int 32

ID/QD/MD/DBD

DINT

REAL

Floating PT 32

ID/QD/MD/DBD

CHAR

Ascii String

DBB String/DBB Char

View the PLC Variables Status

To view the Status of the Variables in the PLC, once you are Online with the PLC, from the Devices Tree of the TIA Portal (SIMATIC STEP7), add or open an existing Watch Table.

Data Block Addressing

Data Block Addressing syntax differs some between what is seen in the TIA Portal (SIMATIC STEP7) and in C-more.  To view the Data Block, double click on the specific Data Block you wish to view.  When a specific Data Block is selected, a window like the one shown below will open.

 

From the figure shown above:

  1. The image above shows DB2.
  2. Inside DB2, there are Four Variables:
    • MOTOR_RPM is addressed at byte0 and is a 16 bit Integer.
    • SETPOINT_RPM is addressed at byte2 and is also a 16bit Integer.
    • START is addressed at byte 4, bit 0 and is a Boolean.
    • STOP is addressed at byte 4, bit 1 and is a BOOLEAN.

If the "Offset" column is not displayed, right-click any column header to Show / Hide Columns.

 

These Four Variables would be Addressed as follows in C-more:

  1. MOTOR_RPM = Memory Type:  DB.DBW  Address:  2.0
  2. SETPOINT_RPM = Memory Type:  DB.DBW  Address: 2.2
  3. START = Memory Type:  DB.DBX  Address:  2.4   Bit:  0
  4. STOP = Memory Type:  DB.DBX  Address:  2.4  Bit:  1
     

SIMATIC Variables Addressing Siemens Vs. C-more

SIMATIC Variable

Siemens Addressing

C-more Addressing

Memory Type

Address

Bit

MOTOR_RPM

DB2.DBW 0

DB.DBW

2.0

 

SETPOINT_RPM

DB2.DBW 2

DB.DBW

2.2

 

START

DB2.DBX 4.0

DB.DBX

2.4

0

STOP

DB2.DBX 4.1

DB.DBX

2.4

1

 

 

 

 

 

Note: Please note that there is a space (shown in red on the Address sample) on all the Siemens Addressing (DB2.DBW 0).

Note:
The information provided above for C-more Addressing is used for the C-more PLC Address fields shown below.

 

Using the Variable #3 as a sample, the Tag Name window from C-more would look as follows:

 

If you view these Variables in the Watch Table of the TIA Portal (SIMATIC STEP7), they look more like the C-more syntax. From the Devices tree add new watch table or open an existing watch table.

The Watch and Force Tables window shown below will open.  From this window you can Monitor the Variables shown.

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