Serial Ports; Real Time Clock - GE 469 Manual

4.2 S1 469 SETUP
S SERIAL PORTS
S [ENTER] for more
The 469 has 3 serial communications ports supporting a subset of the Modbus protocol. The front panel
RS232 has a fixed baud rate of 9600, a fixed data frame of 1 start, 8 data, and 1 stop bits with no parity. The
4
front port is for local use only and responds regardless of the slave address programmed. This port may be
connected to a personal computer running 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 connec-
tion 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 Power Management devices.
S REAL TIME CLOCK
S [ENTER] for more
The correct time and date must be entered for event recorder events to be correctly time/date stamped. A bat-
tery 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.
4-6
ð
SLAVE ADDRESS:
ENTER
254
ESCAPE
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
ð
DATE (MM.DD.YYYY)
ENTER
01/01/1994
ESCAPE
TIME (HH.MM.SS):
ESCAPE
12:00:00
MESSAGE
469 Motor Management Relay
4 SETPOINT PROGRAMMING
Range: 1 to 254, step: 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 secs.

4.2.3 SERIAL PORTS

GE Power Management