Integrating the LES in the process control (Ethernet)
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Integrating the LES in the process control (Ethernet)
10.1
General information
The LES communicates with the process control via UDP/IP using the protocol described
in Chapter 10.2.9. The protocol operates in two different modes:
• Measure mode
• Command Mode
In measure mode, the LES transmits the evaluation telegram. This is continuously trans-
mitted in "Free Running" operation; in triggered operation, it is transmitted only once per
trigger.
In command mode the LES reacts to commands from the control. The commands available
are described in Chapter 10.2.9.
Note!
If you use a firewall, please make certain that the control can communicate with the LES via
the Ethernet interface by means of UDP on ports 9008 and 5634 (these ports are preset at
the factory, but may have been changed by the user, see chapter 7.2 "Menu description").
Furthermore, the firewall must allow ICMP echo messages to pass through for the connec-
tion test (ping).
The integration of PROFIBUS device model LES 36…/PB in the process control via
PROFIBUS is described in Chapter 11 "Integration of the LES 36…/PB in the PROFIBUS"
on page 115.
10.2
Protocol structure: Ethernet
Note!
The sequence in which the individual bytes are saved varies depending on the operating sys-
tem. The commands in Chapter 10.2.9 and the protocol description are represented in "big
endian" format, i.e., the high-byte first followed by the low-byte
(0x… hexadecimal).
Windows PCs (and many controls, such as the Siemens S7), however, store data in the "little
endian" format, i.e. the low byte first followed by the high byte.
If, in your process environment, the LES does not respond to commands from the control
even though communication with LESsoft functions properly, check whether the problem
lies with the byte order.
Example
: for command
0x434E
(Connect to Sensor) a Windows PC must transmit
0x4E
and
0x43
in order for it to be understood by the LES. In the transaction number of the answer
from LES there is then also
0x4E43
(byte sequence 0x43, 0x4E).
The LES sends data as "little endian", i.e., first the low byte and then the high byte.
