10
P
I
P/I Transmitter
P
Input
0V/OUT
+V
+
U
DC current
+
-
-
R
Load
I
4mA
~
20mA
Fig. 7
b)
The electric connection method of transmitter only with RS485
communication to see Figure 8:
P
I
P/I Transmitter
P
Input
RS485A
+V
+
U
DC current
-
Safety
+OUT
RS485B
Computer
barrier
Fig. 8
Note
:
when 4mA ~ 20mA DC output and RS485 signal are used at the
same time, RS485 signal will affect 4mA ~ 20mA DC output signal in
communication, and the degree of influence is related to
communication rate and communication frequency.
c)
Wiring for HART
transmitter connecting with hand-communicator.
to see Figure 9: