Table of Contents
Advertisement
8 Modbus TCP
8 Modbus TCP
The Modbus protocol is a communications protocol based
on a Client/Server architecture. Once the TCP/IP connec-
tion between client (PLC) and server (DG smart) has been
established, useful data can be transferred via this connec-
tion as often and in as great an amount as required. The
PLC and DG smart can establish up to 3 parallel TCP/IP
connections at the same time. Using the function codes
3, 6 and 16, data can be transferred to and from the DG
smart. New data are available every 100 ms.
8 . 1 Modbus holding registers
Communication with Modbus TCP is achieved using TCP
port 502 and the IP address.
The holding registers (16-bit values, read and write (r/w)) are
addressed using an internal register number. Alle registers =
r; register 001 = r/w.
The data ranges can be read in each register or, if it exists,
in summary form using a register number.
DG smart · Edition 09.23 · EN
8 . 1 . 1 Process data
Register Description
101
Relative pressure at P1
102
Relative pressure at P2
103
Differential pressure
104
Supply voltage
105
Device temperature
106
4–20 mA analogue output signal
107
Error code
108
Warning code
109
Device status
110
Operating status
111
MAX switching point
112
MIN switching point
Status bits:
Bit 0: MAX warning
Bit 1: MAX alarm
Bit 2: MAX switching point detected
113
Bit 3: MIN warning
Bit 4: MIN alarm
Bit 5: MIN switching point detected
Bit 6: Supply voltage OK
001
Remote reset via bus
Value range/Unit
mbar (signed)
mbar (signed)
mbar (signed) * 10
V * 10
K * 10
mA * 10
0 = Initialization
1 = Normal operation
5 = Device error
9 = Safety shut-down
10 = Fault lock-out
0 = Initialization
1 = Normal operation
4 = Underpressure warn-
ing
5 = Underpressure error
6 = Overpressure error
7 = Temperature drift er-
ror
8 = Sensor drift error
9 = Defective sensor
mbar * 10
mbar * 10
20
Advertisement
Table of Contents
