8.2 Modbus
The controller supports the Modbus TCP/IP protocol. A PX345 controller
operates as a server (slave), to which an application / a device operating as a
client (master) connects. The master establishes a connection through TCP
port 502 (a standard Modbus port) using the current IP address of the
controller. At any given time, only one master can be connected to the
controller.
In Modbus TCP protocol, data are transmitted in packets referred to as
ADUs (Application Data Unit). An ADU is composed of a header (MBAP
Header) and a PDU (Protocol Data Unit). According to the standard, all data
sent using Modbus protocol are represented as Big endian (most significant
byte coming first).
41
ON/OFF INPUTS
SMART-
PHONE
E
V
E
N
T
S
L
IS
T
O
F
A
C
T
IO
N
O
U
T
P
U
T
C
H
A
N
N
E
L
S
P
E
C
IF
IC
A
T
IO
N
S
DMX
OUTPUT
RTC
CLOCK
ASTRONO-
MICAL
CLOCK
V
A
L
U
E
C
A
L
C
U
L
A
T
IO
N
