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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.
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| Parameter | Meaning | Unit / size | Default value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| A mode of communication:
Note: Active communication is used when Control Web is replaced by D2000. | 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 |
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