17.7.17
UNIGATE
®
fieldbus gateway UNIGATE
®
MB - EtherCAT
®
V. 1.4
19
Deutschmann Automation GmbH & Co. KG
Implemented protocols in UNIGATE® MB
8.2.2
Fieldbus parameters
Trigger byte: See "The trigger byte", Chapter 8.5‚ on page 23
Length byte: See "The length byte", Chapter 8.6‚ on page 23
8.2.3
RS232 parameter table
8.2.3.1
Start character (232 Start character)
If this character is defined, the gateway evaluates only the data at the RS232 interface following
this start character. Each transmission from the gateway via the RS232 interface is initiated with
the start character in this case.
8.2.3.2
Length 232 (232 Length)
If this byte is activated, the gateway, at the receive end, awaits as many bytes of useful data as
specified in this byte by the RS232 transmitter. At the transmission end, the gateway then sets
this byte to the number of useful data items transmitted by it. If byte "Length232" is not defined,
the gateway, on reception at the RS232 interface, waits for the end criterion if this is defined. If no
end criterion is defined either, as many characters as can be transferred in the fieldbus transmit
buffer are read in via the RS232 interface.
As a special case for this parameter also a length byte with additional Timeout monitoring can be
set in WINGATE. In that case the received characters will be discarded at a Timeout.
Attention:
If "Timeout“ is selected as end character, then this byte has no significance.
8.2.3.3
End character (232 End character)
If this character is defined, the gateway receives data from the RS232 interface up to this charac-
ter. The "Timeout" criterion can be defined as a special case. In this case, the gateway continues
to receive characters until a defined pause occurs. In the special case "Timeout" the "Length
232-byte" has no significance. At the transmit end, the gateway inserts the end character, if
defined, as the last character of a transmission.
8.2.4
Communication sequence
The useful data (data area) arriving via the fieldbus is copied in accordance with chapter 8.2.1
transparently into the RS232 data field and transferred via the RS interface, whereby the protocol
is supplemented in accordance with the configuration (start character, end character...). NO
acknowledgement is issued !
If the "Trigger byte“ (see chapter 8.5) is active, data is sent only on a change of this byte. If the
"Length byte" (see chapter 8.6) is active, only as many of the following bytes as specified there
are transferred.
Receive data at the RS interface is evaluated in accordance with the configured protocol, and the
data field (data area (see chapter 8.2.1)) is sent to the fieldbus Master. If more characters have
been received than the fieldbus block length, the trailing bytes are truncated and an Rx Overrun
is indicated. If less have been received, padding with 0 occurs. If the "Length byte" is active, the
number of received useful data items is entered there. If the, "Trigger byte" is active, this is incre-
mented by one after each complete reception operation at the RS interface.
Summary of Contents for UNIGATE MB EtherCAT
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