SATEC SLC500 - Manual (Page 24)

24
C.3.2 RS-485 Connection with Surge Voltage Protection
TxD
RxD
TxD-
RxD-
TxD
6
7
1
9
TxD'
1746-BAS BASIC module
DB9 male connector
DB9 female connector
2
3
RxD-
TxD-
RxD
TxD
6
7
DB9 male connector
RxD-
TxD-
RxD
TxD
Series PM-290H Powermeters
Series PM-170 Powermeters
8
9
14
15
16
17
DB25 male connector
5
* A termination resistor should only be connected at the furthest end of the cable
COM
Z1
Z2
Z3
Z4
R1
Ω
Ω
R3
Z1,Z3 - 1N4736A
Z2,Z4 - 1N4728A
Series PM-270/290 Powermeters
R4
*R2
R1,R2 - 120
R3,R4 - 33