GE Multilin 850, Instruction Manual

Page: 183 / 664

CHAPTER 5: DEVICE, SYSTEM, INPUT AND OUTPUT SETPOINTS DEVICE
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 5–21
RS485
On the rear card 8 Series relays are equipped with one RS485 serial communication port
and one 10/100 Mbps Ethernet port. The RS485 port has settings for baud rate and parity.
It is important that these parameters agree with the settings used on the computer or
other equipment connected to this port. A maximum of 32 relays can be daisy-chained
and connected to a DCS, PLC or a PC using the RS485 port.
Path :
Setpoints > Device > Communications > RS485
BAUD RATE
Range: 9600, 19200, 38400, 57600, 115200
Default: 115200
PARITY
Range: None, Odd, Even
Default: None
PORT PROTOCOL
Range: Modbus, DNP 3.0, IEC 60870-5-103
Default: Modbus
WiFi
WiFi refers to Wireless Local Area Networks (WLANs) that are based on the 802.11 set of
standards. WLANs are essentially providing Local Area Network (LAN) type of connectivity
but without the need of cables, which makes them more convenient for use in limited
spaces. WiFi works on top of the TCP/IP stack, the same as Ethernet. The signal strength
and its range is determined by the wireless device’s antenna technology and standard, the
best being IEEE 802.11n.
WiFi defines two modes of operation, namely ad-hoc, used for small deployments, and
infrastructure mode, which supports more robust types of security and better capabilities
for centralized management. The infrastructure mode requires an access point (AP).
Devices operating in this mode pass all data through the AP.
The WiFi module integrated on the 8 Series products conforms to IEEE 802.11b/g/n
standards. The 8 Series devices operate in infrastructure mode. Security is optional, but
enabled by default and it is advisable that it is left on, as wireless traffic is very susceptible
to cyber-attacks.
The security technology used is WPA2 (Wireless Protected Access version 2), based on the
IEEE 802.11i standard for data encryption. WPA2 is a second version of WPA technology,
designed to solve known security limitations found in one of the encryption algorithms
used by WPA, namely TKIP (Temporal Key Integrity Protocol). WPA2 uses CCMP (Counter
Mode with Cipher Block Chaining Message Authentication Code Protocol), which provides
an enhanced data cryptographic encapsulation mechanism based on AES (Advanced
Encryption Standard). CCMP makes WPA2 much stronger and secure than its
predecessors, WPA and WEP.
Several forms of WPA2 security keys exist. The 8 Series supports WPA2 PSK (Pre-Shared
Key), which utilizes 64 hexadecimal digits. The key may actually be entered as a string of
64 hexadecimal digits or as a passphrase of 8 to 32 printable ASCII characters. For user
convenience, the settings accept the key in the form of a passphrase. Internally the ASCII
passphrase is used for deriving a 256-bit key.
Error ID Exception Description
01 ILLEGAL FUNCTION The function code transmitted is not one of the
functions supported by the 850.
02 ILLEGAL DATA ADDRESS The address referenced in the data field transmitted
by the master is not an allowable address for the 850.
03 ILLEGAL DATA VALUE The value referenced in the data field transmitted by
the master is not within range for the selected data
address.