Implemented Protocols - Ethernet/Ip; Protocol Delta Exchange; The Trigger Byte - DEUTSCHMANN AUTOMATION UNIGATE CX-EtherNet/IP 2Port CANopen Manual

Implemented protocols in UNIGATE® CX C4Map
7.2

Implemented Protocols - EtherNet/IP

In addition to the "Delta exchange" protocol, the universal script also contains other protocols.
However, these cannot be used for communication with the "CANopen (Mapping)" protocol.
7.2.1

Protocol Delta exchange

The Delta exchange protocol can only be used from version 1.9.0 of the universal script Deutsch-
mann.
With this protocol, data can be specifically copied to an area on the fieldbus output side, i.e. from
®
the UNIGATE to the PLC.
To do this, two control parameters, the address offset and the number of bytes, are required at
the start of the transfer before the actual user data then follows. First comes the address offset
(Word), then the number of bytes (Word), then the user data as a byte array.
The two parameters (address offset and number of bytes) must be sent with every data transfer.
1st byte address offset high
2nd byte address offset low
3rd byte number of bytes high
4th byte number of bates low
5th byte user data 1st byte
6th byte "2nd byte
7. "...
Example:
1st byte 0x00
2nd byte 0x02
3rd byte 0x00
4th byte 0x05
5th byte 0x01
6th byte 0x02
7th byte 0x03
8th byte 0x04
9th byte 0x05
In the fieldbus output data, the data is sent to the PLC as follows
sent: 0x00 0x00 0x01 0x02 0x03 0x04 0x05 0x00 ...
7.3

The trigger byte

Since the data is always transmitted cyclically with EtherNet/IP, the gateway must recognize
when the user wants to send new data via the serial interface. This is usually done by the gate-
way comparing the data transmitted via the EtherNet/IP with the internally stored old data - data
exchange on change (Data exchange -> On Change). In some cases, however, this cannot be
used as a criterion, e.g. if the same data should always be sent. For this reason, the user can set
that he wants to control the sending via a trigger byte (Data exchange -> On Trigger). In this
mode, the gateway always sends (and only) when the trigger byte is changed.
Accordingly, in normal mode, the application program in the controller cannot recognize whether
the gateway has received several identical telegrams. If the trigger byte mode is switched on, the
gateway increments the trigger byte each time a telegram is received.
22 Fieldbus-Gateway UNIGATE
Deutschmann Automation GmbH & Co. KG
®
CX EtherNet/IP - C4Map . 1.0 29.9.20