GHM DeltaOHM HD51.3D Series, Operating Manual

Page: 14 / 42

HD51.3D…
- 14 -
V2.0
5.2.1 RS232
SERIAL CONNECTION
TX-
RX+
GND
V+
V -
1 2 3 4 5
6 7 8 9
TX
PC
15
1
2
3
4
5
6
7
11
12
13
14 16
17
18
19
RX
8
10
9
Lmax = 15m
V+
V -
For RS232 connection, TX-, RX+ and serial GND signals (pin 9, 3 and 8 of M23 connector) are
used, to be connected respectively to RX, TX and GND signals of RS232 port on PC (pin 2, 3
and 5 of 9-pole SubD connector). The length of RS232 cables should not exceed 15
m.
5.2.2 RS485
SERIAL CONNECTION
15
1
2
3
4
5
6
7
11
12
13
14 16
17
18
19
8
10
9
DATA+
DATA-
GND
V+
V -
220Ω
220Ω
Shield Shield
Lmax = 1200m
TX+
TX-
GND
V+
V -
DATA+
DATA-
Thanks to RS485 connection, multiple instruments can be connected to a multi-point network.
Instruments are connected in sequence through a twisted-pair shielded cable for signals and a
third wire for ground.
Line terminations should be placed at the two ends of the network. The cable shield should be
connected to both ends of the line.
The maximum number of devices that can be connected to the RS485 line (Bus) depends on the
load characteristics of the devices to be connected. The RS485 standard requires that the total
load does not exceed 32 unit loads. The load of an HD51.3D4R… anemometer is equal to ¼ of
unit load. If the total load is greater than 32 unit loads, divide the network into segments and
Reference of female
connector (solder side)
Power supply
Power supply
RS232 Port
PLC, datalogger or
RS485/USB or RS485/RS232
converter for PC
Other sensors with
RS485 output
Termination
Termination
Reference of female
connector (solder side)