Serial Ports - GE 489 Instruction Manual

4.2 S1 489 SETUP
Some of the 489 characteristics can be modified to suit different situations. Normally the
points group will not require any changes.
• DEFAULT MESSAGE CYCLE TIME: If multiple default messages are chosen, the display automatically cycles
through these messages. The messages display time can be changed to accommodate different reading rates.
• DEFAULT MESSAGE TIMEOUT: If no keys are pressed for a period of time then the relay automatically scans through
a programmed set of default messages. This time can be modified to ensure messages remain on the screen long
enough during programming or reading of actual values.
• PARAMETER AVERAGES CALCULATION PERIOD: The period of time over which the parameter averages are cal-
culated may be adjusted with this setpoint. The calculation is a sliding window.
• TEMPERATURE DISPLAY: Measurements of temperature may be displayed in either Celsius or Fahrenheit. Each
actual value temperature message will be denoted by either °C for Celsius or °F for Fahrenheit. RTD setpoints are
always displayed in Celsius.
• WAVEFORM TRIGGER: The trigger setpoint allows the user to adjust how many pre-trip and post-trip cycles are
stored in the waveform memory when a trip occurs. A value of 25%, for example, when the
is "7 x 16" cycles, would produce a waveform of 4 pre-trip cycles and 12 post-trip cycles.
BUFFER
• WAVEFORM MEMORY BUFFER: Selects the partitioning of the waveform memory. The first number indicates the
number of events and the second number, the number of cycles. The relay captures 12 samples per cycle. When more
4
waveform captures occur than the available storage, the oldest data will be discarded.
PATH: SETPOINTS S1 489 PREFERENCES

SERIAL PORTS

[ENTER] for more
The 489 is equipped with 3 independent serial communications ports supporting a subset of Modbus RTU protocol. The
front panel RS232 has a fixed baud rate of 9600 and a fixed data frame of 1 start/8 data/1stop/no parity. The front port is
intended for local use only and will respond regardless of the slave address programmed. The front panel RS232 program
port may be connected to a personal computer running the 489PC software. This program may be used for downloading
and uploading setpoint files, viewing measured parameters, and upgrading the 489 firmware to the latest revision.
For RS485 communications, each relay must have a unique address from 1 to 254. Address 0 is the broadcast address
monitored by all relays. Addresses do not have to be sequential but no two units can have the same address or errors will
occur. Generally, each unit added to the link will use the next higher address starting at 1. Baud rates can be selected as
300, 1200, 2400, 4800, 9600, or 19200. The data frame is fixed at 1 start, 8 data, and 1 stop bits, while parity is optional.
The computer RS485 port is a general purpose port for connection to a DCS, PLC, or PC. The Auxiliary RS485 port may
also be used as another general purpose port or it may be used to talk to Auxiliary GE Multilin devices in the future.
4-8
SERIAL PORTS
ð
SLAVE ADDRESS:
ENTER
ð
ESCAPE 254
COMPUTER RS485
ESCAPE
BAUD RATE: 9600
MESSAGE
COMPUTER RS485
ESCAPE
PARITY: None
MESSAGE
AUXILIARY RS485
ESCAPE
BAUD RATE: 9600
MESSAGE
AUXILIARY RS485
ESCAPE
PARITY: None
MESSAGE
PORT USED FOR DNP:
ESCAPE
None
MESSAGE
DNP SLAVE ADDRESS:
ESCAPE
255
MESSAGE
DNP TURNAROUND
ESCAPE
TIME: 10 ms
MESSAGE
489 Generator Management Relay
S1 489 SETUP
WAVEFORM MEMORY
4.2.3 SERIAL PORTS
Range: 1 to 254 in steps of 1
Range: 300, 1200, 2400, 4800, 9600, 19200
Range: None, Odd, Even
Range: 300, 1200, 2400, 4800, 9600, 19200
Range: None, Odd, Even
Range: None, Computer RS485, Auxiliary RS485,
Front Panel RS232
Range: 0 to 255 in steps of 1
Range: 0 to 100 ms in steps of 10
4 SETPOINTS
set-
PREFERENCES
GE Multilin