Siemens LR 460 User Manual
Page 20
SITRANS LR 460 – INSTRUCTION MANUAL
7ML19985JM01
m
mmmm
Wi
rng
HART wiring
Install in accordance with
Wiring and Installation
in the HART Application Guide (order
number HCF_LIT-34), available from: http://www.hartcomm.org/technical/doclist.html.
Connecting HART
Typical PLC/mA configuration with HART
3.
Connect the earth conductor of the power supply to the earth terminal
on the
metal bracket inside the enclosure. Adjust the cable length so that the earth
conductor would be last to disconnect if cable is pulled.
conductor would be last to disconnect if cable is pulled.
Note:
LR 460 HART requires no power from the 4-20 mA loop.
Notes:
•
For error-free communication via the HART protocol, a 250 Ohm resistor may be
required if the loop resistance is less than 250 Ohms.
required if the loop resistance is less than 250 Ohms.
•
Only one HART communication device should be inserted in the loop.
1 2
6
4 5
3
7 8
L
1
L
2
N
mA
Rated temperature of
connection cables must
exceed maximum ambient
temperature by at least 15 K
connection cables must
exceed maximum ambient
temperature by at least 15 K
AC version
earth
terminal
cable clamp
1 2
6
4 5
3
7 8
mA
19-30 V
Rated temperature of
connection cables must
exceed maximum ambient
temperature by at least 15 K
connection cables must
exceed maximum ambient
temperature by at least 15 K
DC version
earth
terminal
cable clamp
PLC with mA
input card
PC/laptop with
HART modem
running PDM
LR 460
R
= 250
Ω
HART
Communicator
375