DEUTSCHMANN AUTOMATION UNIGATE RS232/422, Инструкция по эксплуатации, Страница: 25 / 67

29.4.11 UNIGATE fieldbus gateway for ProfibusDP V. 4.7 25
Deutschmann Automation GmbH & Co. KG Implemented protocols in UNIGATE RS
9.3.4 State of the 3964R communication
The current state of the 3964R communication will be mapped in the fieldbus, if the parameter
3964R is activated in WINGATE. The states can be taken from the below table. This parameter
takes effect from software revision 3.41 on and can be adjusted by means of the WINGATE soft-
ware.
This information is only presented in the bus data from the gateway to the Master, however, it
applies to the communication via 3964R in both directions.
9.4 The RK512-protocol
The RK512-protocol is based on the Siemens protocol 3964R, which represents the layer 2 and
RK512 describes the transport layer that is put on it. For the exact sequence 3964R, please take
a look at the preceding chapter.
The complete RK512-protocol, where "consecutive telegrams" are used for the transmission of
any data lengths, can not be supported by the gateway, as consequently the handshake to the
fieldbus master is getting more complex as when the gateway processes only 3964R and the
higher protocol (4 byte receipt and if necessary reply data) are handled directly by the fieldbus
master.
But UNIGATE supports a simple kind of the RK512-protocols, whereas the data exchange is
restricted to one word (fixed) though.
UNIGATE reduces larger data lengths to one word on the part of the RS-side.
For this the end user does not have to care about the problems of quasi-full-duplex operation,
since he receives a fixed reply to any command.
And apart from that the complete data exchange takes place through 8 Byte I/O, which can be
handled by any PLC very easily and quickly.
In detail the data exchange takes place as follows:
|
+-->cxxaxxxx [x = possible commands: 41H(=Send-DB), 45H(=Fetch), 4FH(=Send-DX)]
| |
|
+-- Toggle bit reply (after switch on = 0)
+------- Toggle bit command (after switch on = 0)
Attention:
The gateway is always using "Even Parity", as stipulated in the specifica-
tion.
Name Value Description
3964R_NO_ACTION 0 If this value is presented, no 3964R communication is active.
3964R_WAIT_AFTER_STX 1 After the transmission of the STX character the sender waits until
the receiver has sent its confirmation.
3964R_WAIT_QUITTUNG 2 The receipt character is waited for.
3964R_WAIT_DATA 5 The gateway waits as reveiver for the useful data.
3964R_WAIT_ZVZ 9 An execution time is waited for.
Data structure (identical for both directions):
Byte 1 2 3 4 5 6 7 8
Cmd Typ DB DW DatH DatL ReplyH ReplyL
= RK512-Byte 3 4 5 6 11 12