Siemens SIMATIC 3964(R) communication protocol CW
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 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.
| Kotva |
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| komunikacna_linka |
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| komunikacna_linka |
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Communication line configuration
| Kotva |
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| linka_parametre |
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| linka_parametre |
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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 |
|---|
| A mode of communication: - Active - active communication (sending requests and receiving replies).
- Passive - eavesdropping of Control Web communication with the PLC. PLC responses are intercepted.
- Passive (duplex) - eavesdropping of Control Web communication with the PLC. 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 |
| 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 |
| Maximum number of request retries in case of communication error. | - | 2 |
| A delay before resending a request in case of communication error. | ms | 100 ms |
| 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 |
| Kotva |
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| komunikacna_stanica |
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| komunikacna_stanica |
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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 |
|---|
| Delay between response readings till its finalization. | ms | 50 ms |
| Repetition count of response readings till its finalization. | - | 600 |
| 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 |
I/O tag configuration
Possible I/O tag types: Ai, Ci, Di.
The I/O tag address is compatible with the I/O tag addressing in the Siemens SIMATIC S7 ISO on TCP protocol with the following limitations:
- only "DB" addresses can be used, i. e. only variables in data blocks are available.
- the protocol implements a 1-byte address of the data block, i. e. it supports addressing of data blocks 0-255
- all value types except STRING are available:
| 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). |
| DT | Date and Time, 8 bytes in BCD format. |
| TIME | Time (32 bits signed) in ms. |
| TOD | Time of day (32 bits unsigned) in ms. |
- address examples:
DB3,REAL0
DB3,W4
DB3,B6
Literature
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Changes and modifications
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Document revisions
- Ver. 1.0 - January 16th, 2020 - document creation.