Serial Communications - GE Multilin 350 Series Instruction Manual

ELECTRICAL INSTALLATION

2.2.9 Serial communications

SCADA, PLC, OR
PERSONAL COMPUTER
(*) TERMINATING IMPEDANCE AT EACH END
(typically 120 ohms and 1 nF)
2–14
Courtesy of NationalSwitchgear.com
A wet contact has one side connected to the positive terminal of an external DC power
supply. The other side of this contact is connected to the required contact input terminal. In
addition, the negative side of the external source must be connected to the relay's DC
negative rail at Terminal C11. The maximum external source voltage for this arrangement
is 300 V DC.
Figure 2-13: Wet contact connections
Wet Contact Connection
Contact Input Common C11
Figure 2-14: RS485 wiring diagram
Z T (*)
OPTOCOUPLER
DATA
COM
GROUND THE SHIELD AT THE
SCADA/PLC/COMPUTER ONLY
OR THE 350 ONLY
UP TO 32 350
OR OTHER IEDs,
MAXIMUM CABLE
LENGTH OF
1200 m (4000 ft.)
One two-wire RS485 port is provided. Up to 32 350 IEDs can be daisy-chained together on
a communication channel without exceeding the driver capability. For larger systems,
additional serial channels must be added. Commercially available repeaters can also be
used to add more than 32 relays on a single channel. Suitable cable should have a
characteristic impedance of 120 ohms (for example, Belden #9841) and total wire length
should not exceed 1200 meters (4000 ft.). Commercially available repeaters will allow for
transmission distances greater than 1200 meters.
350 RELAY
Contact Input 1 C1
V DC Power
Supply
TWISTED PAIR
SHIELD
E2
D2
E3
Z T (*)
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 2: INSTALLATION
LOGICIN.CDR
350 IED
RS485 +
OPTOCOUPLER
RS485 -
DATA
COMMON
IED
RS485 +
RS485 -
COMMON
IED
RS485 +
RS485 -
LAST
COMMON
DEVICE
898738S1.CDR