2.10.19
UNIGATE
®
CX V. 1.4
43
Deutschmann Automation GmbH & Co. KG
Optional bus parameter
8
Optional bus parameter
8.1 The trigger byte
If the data is always transmitted cyclically, the gateway must recognize when the user wants to
send new data. This is usually done by having the gateway compare the data being transferred
with the old data stored internally - data exchange on change (Fieldbus Data Exchange → On
Change).
In some cases, this can not be used as a criterion, e.g. B. if always the same data should be
sent. For this reason, the user can set that he wants to control the transmission via a trigger byte
(Fieldbus Data exchange → On Trigger). In this mode, the gateway always (and only) sends
when the trigger byte is changed.
If Trigger-Byte mode is activated, the gateway increments the trigger byte each time a telegram
is received. The first byte in the fieldbus input / output data buffer is used as trigger byte if this
mode is switched on.
8.2 The length byte
The user can configure whether the transmit length is also to be stored as a byte in the input/out-
put data area (Fieldbus lengthbyte
→
active). In transmit direction, as many bytes as specified in
this byte are sent. On reception of a telegram the gateway enters the number of characters
received.
8.3 Swap word
With activated "Swap word" the data is word-swapped to and from the fieldbus. I.e. High and Low
byte are word-swapped and transferred in a 16-bit word. It affects the entire fieldbus Buffer.
