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types S7-300 and S7-400 equipped by an ethernet interface for the communication S7 ISO over TCP.
types S7-1200, S7-1500
types Siemens LOGO
Siemens Microbox

Note: communication via Profinet/Profibus adapter ACCON-NetLink-PRO compact produced by company DELTALOGIC has been verified. Communication with multiple S-300 series PLCs on Profibus worked after firmware upgrade of adapter to version V2.54 (31. march 2015) with adapter's BIOS version V2.39 (7. june June 2011). When the adapter's firmware was version V2.37 (8.august 2011), communication could not be correctly established.
Note: communication with PLC Siemens LOGO was tested. A part of memory that is accessible for readreading/write writing is the V area that is seen as DB1.
Note: the protocol has a "big endian" data representation.

Kotva
komunikacna_linka
komunikacna_linka
Communication line configuration

...

Communication line category: TCP/IP-TCP, TCP Redundant.
IP address (addresses) is set according to a network configuration of a specific device Siemens SIMATIC device.
Port The port number is 102 (according to specification RFC 1006).
Line The line number is not used, set on 1.

When the communication line is set as TCP Redundant you can configure an IP address and port of a backup device. If a communication process lost the connection or is unable to connect to the device, it will switch periodic periodically between the configured devices. KOM process tries to connect to a primary device at first.
Note: Multiple IP addresses of primary/backup device can also be configured (separated by commas or semicolons).

Kotva
linka_parametre
linka_parametre
Line protocol parameters

...

A dialog window of of communication line configuration - Protocol parameters tab.
They influence some optional protocol parameters.

The following line protocol contains the following parameters are defined:

Parameter

Meaning

Unit / size

Default value

Kotva

	rack
	rack

Rack

Siemens Simatic rack number. Rack 0 is most often used.

0 to 7

0

Kotva

	slot
	slot

Slot

Siemens Simatic slot number. Slot 2 is most often used.

0 to 31

0

Kotva

conres

	s7sub1

conres

	s7sub1

S7 Subnet ID-part 1

Connection Resource

(hex)

Connection resource, it inputs as MSB byte to calculation of the value of Remote TSAP at initialization of ISO Connection-request.
See description of

S7 subnet address sent as a part of Remote TSAP if parameter Use long TSAP

.

is set to True

0x0 to

0xFF

0xFFFF

3

0

Kotva

ltsap

	s7sub2

ltsap

	s7sub2

S7 Subnet ID-part 2 (

Local TSAP (

hex)

ISO Local TSAP (Transport Service Local Point). Source TSAP value at initialization of ISO Connection-request.
See description of

S7 subnet address sent as a part of Remote TSAP if parameter Use long TSAP

.

is set to True

0x0 to 0xFFFF

0x1000

0

Kotva

srcref

	us

srcref

	us

Source ReferenceISO Source Reference. Value of SRC-REF at connection of ISO Connection-request.0 to 655351 KotvaultultUse long TSAPEnables a long format of local and remote TSAP which is sent during connection setup phase.
Short TSAP is

Use Secondary

The parameter allows the use of redundant PLCs, which may differ in the settings of some parameters (Rack, Slot, S7 Subnet ID).

If its value is True, the primary and secondary parameters are used alternately when connecting to the PLC using the specified IP addresses.

-

False

Kotva

	conres
	conres

Connection Resource (hex)

Connection resource, it enters as MSB byte to the calculation of the value of Remote TSAP at initialization of ISO Connection-request.
See the description of parameter Use long TSAP.
Note: in the specific case, when two systems (one of them D2000) needed to communicate with S7-300, they each had to have a different Connection resource, otherwise after sending the initial sequence of D2000 KOM process, the connection broke:

/TSK1/Sending CR-TPDU: CLASS=0, SRC-REF=0x0001, TPDU size=1024, SRC-TSAP=10-00, DST-TSAP=03-02
/TSK1/OUT-<03><00><00><16><11><E0><00><00><00><01><00><C0><01><0A><C1><02><10><00><C2><02><03><02>
recv error '10.94.11.237:102 (handle: 2888, objId: 2563271)' - WSA_ECONNRESET [ 10054] Task: L.N337-S7ExecTsk/TSK1/

After changing the Connection resource from 3 to 2, the communication started working.

0x0 to 0xFF

3

Kotva

	ltsap
	ltsap

Local TSAP (hex)

ISO Local TSAP (Transport Service Local Point). Source TSAP value during the initialization of ISO Connection-request.
See the description of parameter Use long TSAP.

0x0 to 0xFFFF

0x1000

Kotva

	srcref
	srcref

Source Reference

ISO Source Reference. Value of SRC-REF during the initialization of ISO Connection-request.

0 to 65535

1

Kotva

	ult
	ult

Use long TSAP

Enables a long format of local and remote TSAP which is sent during the connection setup phase.
Short TSAP is 2 bytes long.
Short local TSAP has the following format:

1. byte - higher byte of parameter Local TSAP
2. byte - lower byte of parameter Local TSAP

Short remote TSAP has the following format:

1. byte - the value of parameter Connection Resource
2. byte - combination of parameters Rack * 32 + Slot

Long local TSAP is 28 bytes long. Last 2 bytes are higher and lower byte of parameter Local TSAP
Full remote TSAP is 28 bytes long and it contains:

5. byte - higher byte of parameter S7 subnet ID-part 1
6. byte - lower byte of parameter S7 subnet ID-part 1
9. byte - higher byte of parameter S7 subnet ID-part 2
10. byte - lower byte of parameter S7 subnet ID-part 2
11

. byte - value of parameter MPI/Profibus Address

27. byte - value of parameter Connection Resource

28. byte - combination of parameters Rack * 32 + Slot

-False Kotvampiaddrmpiaddr

. byte - the value of parameter MPI/Profibus Address

MPI/Profibus address sent as a part of Remote TSAP, if parameter Use long TSAP is set to True0 to 1261 Kotvas7sub1s7sub1S7 Subnet ID-part 1 (hex)S7 subnet address sent as a part of Remote TSAP, if parameter Use long TSAP is set to True0x0 to 0xFFFF0 Kotvas7sub2s7sub2S7 Subnet ID-part 2 (hex)S7 subnet adresa

27. byte - the value of parameter Connection Resource
28. byte - combination of parameters Rack * 32 + Slot

-

False

Kotva

	mpiaddr
	mpiaddr

MPI/Profibus Address

MPI/Profibus address sent as a part of Remote TSAP, if parameter Use long TSAP is set to True

0x0

0 to

0xFFFF

126

0

1

Kotva

	tpdus
	tpdus

ISO TPDU Size Variable Parameter

Maximum

The maximum required size of ISO TPDU. The parameter

value at

value the initialization of ISO Connection-request.

8192, 4096, 2048, 1024, 512, 256 or 128 bytes

1024 bytes

Kotva

	pnj
	pnj

Nr. of Parallel Network Threads

Maximum parallel communication threads. Increase the value if there is a request on more data read from the device in a shorter time.

1 to 4

1

Kotva

	ct
	ct

Cycle Time

Required

The required time of one data reading cycle.

ms

1000 ms

Kotva

	wt
	wt

Message Timeout

Maximal wait time on a reply from

other

the device.

ms

2500 ms

Kotva

	imd
	imd

Inter Message Delay

Delay which is used before sending a data request. When a high data transfer rate is required, set 0 ms.

sec.ms

20 ms

Kotva

	rd
	rd

Reconnect Delay

Delay before reconnection to

other

the device if the connection has failed or some communication error has occurred.

sec.ms

2 sec

Kotva

	cet
	cet

Connection Error Timeout

When Timeout passes and communication error occurs in all threads, a communication error status is set on the stations. FALSE state is set on the communication line.

sec.ms

20 sec

Kotva

	pdu
	pdu

S7 PDU Size

Maximum PDU in bytes at S7 communication with

other

the device.

240, 480, 960 bytes

480 bytes

Kotva

	tnd
	tnd

Tcp No Delay

Setting Tcp No Delay parameter causes low-level socket option TCP_NODELAY

being

to be set, thus turning off the default packet coalesce feature.

-

False

Kotva

	nvd
	nvd

Debug Values

Activates a debug info about the loaded values of I/O tags. Use this parameter only when communication must be

debug

debugged because it highly uses CPU and slows down the communication.

YES/NO

NO

Kotva

	iopd
	iopd

Debug I/O Binary Packets Info

Activates a debug info about a binary content of packets. Use this parameter only when communication must be

debug

debugged because it highly uses CPU and slows down the communication.

YES/NO

NO

Kotva

	rdd
	rdd

Debug Requests Info

Activates a basic debug info about requested data.

YES/NO

YES

Kotva

	rad
	rad

Debug Answers Info

Activates a basic debug info about received packets.

YES/NO

YES

Kotva
komunikacna_stanica
komunikacna_stanica
Communication station configuration

...

Communication protocol: Siemens SIMATIC S7 ISO over TCP.
No station address, no protocol parameters on the station.
Time The time parameter setting is ignored. See the line parameter Cycle Time.
A time Time synchronization of device is not supported.

...

I/O tag address is a character string according to the following:

{;}{S7:[connectionname]}DB<no>,<type><address>
{;}{S7:[connectionname]}DI<no>,<type><address>
{;}{S7:[connectionname]}<object>{<type>}<address>

...

Time of day (32 bits unsigned) in ms

.

;

Optional parameter. It disables the I/O tag from communication, stops I/O tag address check when it is saved , and can be useful when the communication with the device is activated or debugged.

S7:[connectionname]

Optional parameter. It does not contains contain any useful information but it is supported only because of backward compatibility with Siemens SimaticNET OPC server.

DB

Data block. S7 variable identifier from "Data block".

DI

Instance data block. S7 variable identifier from " Instance data block".

<no>

Number A number of "data block" or "instance data block".

<object>

Specification of block or area in S7 PLC.

Possible values:

Value

Description (German name)

I

Input (Eingang, E)

Q

Output (Ausgang, A)

PI

Peripheral Input ( Peripherie Eingang, PE)

PQ

Peripheral Output ( Peripherie Ausgang, PA)

M

Memory bit (F)

C

Counter (Zähler, Z) -

I

Input

Q

Output

PI

Peripheral input

PQ

Peripheral output

M

Memory bit

C

Counters ( BCD coded integer numbers <0-999>)

T

Timers (Timer (Timer, T) - BCD coded time values from intervals <0.00-9.99>, <00.0-99.9>, <000-999>, <0000-9.9990>)

Kotva

	szl
	szl

S

SZL (System-ZustandsListen - system status listsSystem Status Lists (System-ZustandsListen, SZL) - lists with diagnostic information which that are available on CPU family S7-300 and S7-400. Diagnostic information differs for various classes of PLC and details are described in manuals (e.g. System Software for S7-300/400 System and S7-400. Diagnostic information differs for various classes of PLC and details are described in manuals (e.g. System Software for S7-300/400 System and Standard Functions, Volume 1/2)
Note: I/O tag S must be of TxtI type.Standard Functions, Volume 1/2)
Note: I/O tag S must be of TxtI type.

<type>

Data type of S7. It is not specified for T, C and S objects.

Identifier <type>	Description
X	Bit (boolean). Specify a bit number 0 to 7 - e.g. DB9,X8.3
B	Byte (8 bits unsigned).
W	Word (16 bits unsigned).
D	Double word (32 bits unsigned).
CHAR	Character (8 bits signed).
INT	Integer (16 bits signed).
DINT	Double integer (32 bits signed).
BCD	BCD-coded 2-byte number (0-9 999)
LBCD	BCD-kódované 4-byte number (0-99 999 999)
REAL	Floating point number (32 bits according to IEEE754 standard).
LREAL	Long floating point number (64 bits according to IEEE754 standard).
STRING	String. Specify maximal length of string.
CHARARR	Array of CHARs interpreted as a string. Array length must be specified.
DT	Date and Time, 8 bytes in BCD format.
TIME	Time (32 bits signed) in ms. Note: if the I/O tag is of the TiR type, it is necessary to ensure the conversion by configuring the linear conversion (A=0.001, B=0) on the Conversion tab
TOD	Time of day (32 bits unsigned) in ms.

Note: The CHARARR type is a D2000 extension that allows you to read/write an array of CHARs as a string. This type is not compatible with the Siemens SimaticNET OPC server addressing.
The difference between CHARARR and STRING is as follows:

STRING - standard format of the S7 string, when there are 2 bytes in front of the string itself (maximum and current string length). For example, a 10-character STRING takes up 12 bytes.
CHARARR - array of characters, without a 2-byte header. For example, CHARARR with a length of 10 characters takes up 10 bytes

<type>

Data type of S7. It is not specified for T, C and S objects.

Identifier <type>

Description

X

Bit (boolean). Specify a bit number 0 to 7 - e.g. DB9,X8.3

B

Byte (8 bits unsigned).

W

Word (16 bits unsigned).

D

Double word (32 bits unsigned).

CHAR

Character (8 bits signed).

INT

Integer (16 bits signed).

DINT

Double integer (32 bits signed).

REAL

Floating point number (32 bits according to IEEE754 standard).

LREAL

Long floating point number (64 bits according to IEEE754 standard).

STRING

String. Specify maximal length of string.

DT

Date and Time, 8 bytes in BCD format.

TIME

Time (32 bits signed) in ms.

TOD

<address>

Address of variable. Possible types:

Byte offsetByte offset (offset within a block, a number 0-65535)
Byte offset.bit (only for X data type, bit number in the range of 0 to 7)
Byte offset.String length (only for STRING data type, string length from 1 to 254 characters)
Id.Index[.StringOffset[.StringLength]] - only for object S (system status list):
- Id and Index are 16-bit numbers in range 0-65535 defining ID of specific system status list and index of item in this list
- StringOffset and StringLength are byte offset (0..65535) and length (1..65535) of substring in answer, which will be parsed as a value of I/O tag.
Example: address S237.1.10.20 represents status list 237 (0x0111), index 1 (Identification of the module). S7-300 will answer to this request by a 36 byte-long string (bytes 0..35) in which bytes 10..29 (i.e. offset=10, length=20) represent "Order number of the module", e.g. '6GK7 342-5DA02-0XE0 '.

Example of addresses:

DB10,W35
DB8,X10.0
DB1,REAL12
DB5,STRING5.14
DB5,CHARARR5.14
T20
C7
MB11
MDINT30
QX3.7

<items>

number of elements for structured I/O tags with configured Destination column. Every read element (1,2,3 .. items) will be written to one item of destination column.
Structured I/O tags are not supported for objects of type T (timers), C (counters) and S (system status lists) nor for data type STRING.
Note: All items elements are read at once. If e.g. 100 elements of type D (double word) are configured, it means reading of a block of 400 bytes. If a smaller size of packet (S7 PDU size) is agreed on during establishment of connection, reading of this I/O tag will not be performed and trace file of line will contain an error message. Agreed S7 PDU size is minimum of size offered by D2000 (parameter S7 PDU Size) and supported size of specific device.
Note: syntax of address when specifying number of elements is compatible with Siemens S7 OPC server (e.g. S7:[MyPLC]DB120,INT1050, 24), which facilitates simple transition from OPC communication to Siemens SIMATIC S7 ISO on TCP protokol by configuring a new line, a new station and then changing parent of I/O tags (e.g. via CSV or XML export and import).

Example of addresses:

DB10,W35, 20 a block of 20 words will be read (i.e. 40 bytes) from addresses 35-54
DB8,X10.0, 100 a block of 100 bits will be read (i.e. 13 bytes) from addresses 10-22

...

Ver. 1.0 - September 17, 2010 - Document written.
Ver. 1.1 - July 2, 2020 - Support for CHARARR.
Ver. 1.2 - July 9, 2020 - Support for BCD and LBCD.
Ver. 1.3 - August 27, 2020- Support for Siemens Microbox

Info

title	Related pages:

Communication protocols

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komunikacna_linka
komunikacna_linka
Communication line configuration

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linka_parametre
linka_parametre
Line protocol parameters

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komunikacna_stanica
komunikacna_stanica
Communication station configuration

Strom stránky

História stránky

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Stará verzia 12

Nová verzia Aktuálny

Kľúč

Kotvakomunikacna_linkakomunikacna_linkaCommunication line configuration

Kotvalinka_parametrelinka_parametreLine protocol parameters

Kotvakomunikacna_stanicakomunikacna_stanicaCommunication station configuration

Kotva
komunikacna_linka
komunikacna_linka
Communication line configuration

Kotva
linka_parametre
linka_parametre
Line protocol parameters

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komunikacna_stanica
komunikacna_stanica
Communication station configuration