Serial Ports; Real Time Clock - GE 469 Instruction Manual

4.2 S1 469 SETUP
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PATH: SETPOINTS S1 469 SETUP
n SERIAL PORTS
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The 469 has three (3) serial communications ports supporting a subset of the Modbus protocol. The front panel RS232 has
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a fixed baud rate of 9600, a fixed data frame of 1 start, 8 data, and 1 stop bits with no parity. The front port is for local use
only and responds regardless of the slave address programmed. This port may be connected to a personal computer run-
ning 469PC. The software can download and upload setpoint files as well as upgrade the 469 firmware.
For RS485 communications, each 469 must have a unique address from 1 to 254. Address 0 is the broadcast address
detected 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 uses 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 be
used for redundancy or, it may be used to talk to auxiliary GE Multilin devices.
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PATH: SETPOINTS S1 469 SETUP
n REAL TIME CLOCK
n [ENTER] for more
The correct time and date must be entered for event recorder events to be correctly time/date stamped. A battery backed
internal clock runs continuously even when power is off. It has an accuracy of approximately ±1 minute per month. It must
be periodically corrected manually through the front panel or via the RS485 serial link clock update command. If the
approximate time an event occurred without synchronization to other relays is sufficient, then entry of time/date from the
front panel keys is adequate.
If the RS485 serial communication link is used, then all the relays can keep synchronized time. A new clock time is pre-
loaded into the 469 memory via the RS485 port by a remote computer to each relay connected on the communications
channel. After the computer broadcasts (address 0) a "set clock" command, all relays in the system begin timing at the
same instant. There can be up to 100 ms of delay in receiving serial commands so the clock time in each relay is ±100 ms,
± the absolute clock accuracy in the PLC or PC. See Chapter 6: COMMUNICATIONS for information on programming the
time preload and synchronizing commands.
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Courtesy of NationalSwitchgear.com
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SERIAL PORTS

ð
SLAVE ADDRESS:
ENTER
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
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REAL TIME CLOCK

ð
DATE (MM.DD.YYYY)
ENTER
ESCAPE 01/01/1994
TIME (HH.MM.SS):
ESCAPE
12:00:00
MESSAGE
469 Motor Management Relay
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
4.2.4 REAL TIME CLOCK
Range: 01 to 12 / 01 to 31 / 1995 to 2094
Range: 00 to 23 hrs / 00 to 59 mins. / 00 to 59 sec.
4 SETPOINTS
GE Multilin