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Siemens SIMATIC 3964(R) CW

Siemens SIMATIC 3964(R) CW

júl 10, 2020

Siemens SIMATIC 3964(R) CW communication protocol 

Supported device types and versions 
Communication line configuration
Line protocol parameters
Communication station configuration
I/O tag configuration
Literature
Changes and modifications
Document revisions

Supported device types and versions

The protocol is an implementation of the Control Web "SIMATIC 3964R" protocol and was created to facilitate the replacement of Control Web applications with D2000 technology.

On the link layer, this protocol implements the Siemens SIMATIC 3964R protocol and uses it to read from and write to the PLC. The protocol only supports database block (DB) addressing 0-255.

The protocol contains the following header defined by Control Web:

Byte

Name

Description

1

Id

Zone identifier ('D' = data block)

2

DB

Number of zone (data block)

3-4

DW

Word address within a zone (lower byte, upper byte)

5

Cmd

Command ('R' - reading, 'W' - writing)

6-7

Count

Number of read / written words (lower byte, upper byte)

The protocol supports reading data from control PLC automats of Siemens SIMATIC of the S5 and S7 series. PLC Simatic must be equipped with the serial communication point-to-point modules - for more details see the decription of Siemens SIMATIC 3964(R) protocol.

Communication line configuration

Line protocol parameters

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

The following line protocol parameters are defined:

Parameter

Meaning

Unit / size

Default value

Mode

A mode of communication:

  • Active - active communication (sending requests and receiving replies).

  • Passive - eavesdropping of Control Web communication with the PLC. This mode requires that only PLC responses are intercepted.

  • Passive (duplex) - eavesdropping of Control Web communication with the PLC. This mode requires that both Control Web requests and PLC responses are intercepted.

Note: Active communication is used when Control Web is replaced by D2000.
The eavesdropping is used during D2000 deployment and allows parallel operation with the Control Web system.

Active
Passive
Passive (duplex)

Active

Max Data Size

Maximum size (in bytes) of data read by a single requestl. Add to this size a 7-byte Control Web header to obtain full length of response (without duplicated DLE bytes) according to the SIMATIC 3964(R) standard.

4 až 249 B

128 B

Retry Count (hex)

Maximum number of request retries in case of communication error.

-

2

Retry Timeout

A delay before resending a request in case of communication error.

ms

100 ms

Debug Values

Activates a debug info about the loaded values of I/O tags. Use this parameter only when communication must be debug because it highly uses CPU and slows down the communication.

YES/NO

NO

Communication station configuration

  • Communication protocol: Siemens SIMATIC 3964(R) CW.

  • No address is specified, only a single Simatic PLC can be attached to one communication line.

 

Station protocol parameters

The Communication station dialog box - tab Protocol parameters.
Parameters defined in the input field have effect on some optional protocol parameters. The following station protocol parameters can be defined (the same as parameters of protocol Siemens SIMATIC 3964(R))::

Table 1

Parameter

Meaning

Unit

Default value

Wait Timeout

Delay between response readings till its finalization.

ms

50 ms

Max Wait Retry

Repetition count of response readings till its finalization.

-

600

3964 (without BCC)

Enable the 3964 protocol, i.e. version with no transmission security using the checksum. By default, the 3964R protocol with the BCC checksum is used.

YES/NO

NO