Table 392: EIA-485 interface
Type Value Conditions
Minimum differential
driver output voltage
1.5 V —
Maximum output current 60 mA —
Minimum differential
receiver input voltage
0.2 V —
Supported bit rates 300, 600, 1200, 2400,
4800, 9600, 19200,
38400, 57600, 115200
—
Maximum number of
650 IEDs supported on
the same bus
32 —
Max. cable length 925 m (3000 ft) Cable: AWG24 or better, stub lines shall be avoided
Table 393: Serial rear interface
Type Counter connector
Serial port (X9) Optical serial port, type ST for IEC 60870-5-103
and DNP serial
Table 394: Optical serial port (X9)
Wave length
Fibre type Connector
Permitted path attenuation
1)
820 nm MM 62,5/125 µm
glass fibre core
ST 6.8 dB (approx. 1700m length with 4 db /
km fibre attenuation)
820 nm MM 50/125 µm
glass fibre core
ST 2.4 dB (approx. 600m length with 4 db /
km fibre attenuation)
1) Maximum allowed attenuation caused by fibre
17.8 Enclosure class
Table 395: Degree of protection of rack-mounted IED
Description
Value
Front side IP 40
Rear side, connection terminals IP 20
Table 396: Degree of protection of the LHMI
Description
Value
Front and side IP40
1MRK 505 277-UUS C Section 17
Technical data
453
Technical Manual