Supported device types and versions
Communication line configuration
Communication station configuration
I/O tag configuration
Literature
Changes and modifications
Document revisions
The protocol allows reading and writing data from control PLC automats of Siemens Simatic of the S5 and S7 series. PLC Simatic must be equipped with the following serial communication point-to-point modules:
The protocol RK512 is transport superstructure of the protocol 3964(R). It allows universal reading and writing values of PLC Simatic objects - minimal intervention into the PLC application software (using the STEPS5/7 programming language).
The 3964 protocol, that is the line layer of the RK512 protocol, has two variants - 3964 a 3964R. The 3964R allows extra data security using the BCC checksum.
The Communication station configuration 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:
Table 1
| Parameter | Meaning | Unit / size | Default value |
|---|---|---|---|
| Poll repetition count in case of a communication error. | - | 2 | |
| Delay between poll repetition in case of a communication error. | ms | 100 ms | |
| First waiting for response after sending the poll. | ms | 100 ms | |
| Delay between response readings till its finalization. | ms | 50 ms | |
| Repetition count of response readings till its finalization. | - | 40 | |
| Enable the 3964 link protocol, i.e. version with no transmission security. By default, there is used the 3964R protocol using the BCC checksum. | YES/NO | NO | |
| CPU identification (1 up to 4), not used by default (value = 0). | 0,1,2,3,4 | 0 |
Possible I/O tag value types: Ai, Ao, Ci, Co, Di, Do.
I/O tag address is a character string as follows:
Table 2
| Data | Format | Description | Access | I/O tag type |
|---|---|---|---|---|
| Data block/Extended data block elements | D{B|X}mD{L|R|W|D}n[x] | m = "data block" number n = word offset in the data block x = suffix KF,KG (as necessary - see Note 1) | R/W | Ai,Ao,Ci,Co |
| Data block bits | D{B|X}mDn.k | m = "data block" number n = word offset in the data block k = bit position [0..15] | R/W | Di,Do |
| Memory elements | F{Y|W|D}n[x] or M{B|W|D}n[x] | n = byte offset in "memory area" x = suffix KF, KG (as necessary - see Note 1) | R | Ai,Ci |
| Memory bits | Fn.k or Mn.k | n = byte offset in "memory area" k = bit position [0..7] | R | Di |
| Input elements | I{B|W|D}n[x] or E{B|W|D}n[x] | n = byte offset in "input area" x = suffix KF, KG (as necessary - see Note 1) | R | Ai,Ci |
| Input bits | In.k or En.k | n = byte offset in "input area" k = bit position [0..7] | R | Di |
| Output elements | Q{B|W|D}n[x] or A{B|W|D}n[x] | n = byte offset in "output area" x = suffix KF, KG (as necessary - see Note 1) | R | Ai,Ci |
| Output bits | Qn.k or An.k | n = byte offset v "output area" k = bit position [0..7] | R | Di |
The table 2 contains the address format used in SIMATIC S5, i.e. use of word offset in DB and DX elements. Therefore you can use addresses in the S7 format according the table 3 for DB and DX elements:
Table 3
| Data | Format | Description | Access | I/O tag type |
|---|---|---|---|---|
| Data block/Extended data block elements | D{B|X}m.DB{B|W|D}n[x] | m = "data block" number n = byte offset in data block x = suffix KF, KG (as necessary - see Note 1) | R/W | Ai,Ao,Ci,Co |
| Data block bits | D{B|X}m.DBXn.k | m = "data block" number n = byte offset in data block k = bit position [0..7] | R/W | Di,Do |
Explanatory text:
Note 1:
Suffix is optional as follows:
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