Front Rs-232C Communications Port; Communications Port Set Up; Operations - ABB REL 301 Instruction Leaflet

ting changes via the MMI. Blocking the front panel setting changes, may be useful for situations
in which the access to the relay cannot be secured from tampering by unauthorized persons.
Password:
When the REL 301/302 is received from the factory of if the user loses the relay password, a
new password can be assigned with the following procedure:
Turn off the relay dc supply voltage for a few seconds,
Restore the dc supply voltage and wait for the relay to complete the self check/start-up rou-
tine,
Using RCP, perform the Password Menu choice "Set Relay Password",
Use the word "password" when prompted for the "current relay password" and
Then enter a new password.
Password setting change procedure must be completed within 15 minutes of energizing relay
or "password" will not be accepted as the "current" password.
4. 7.

FRONT RS-232C COMMUNICATIONS PORT

4.7.1

Communications Port Set Up

The front RS-232C comm. port, on the relay, consists of a printed circuit board that plugs flat
into the rear of the microprocessor module. On the front panel, of the relay, is the 9-pin (DB-9S)
DCE connector with it's associated enabling push-button, next to the connector. As described
above, communications with the relay requires a serial cable from the comm. port to the com-
municating device (usually a local PC).
The front comm. port data rate must match the comm. port data rate of the device connected to
the port. This data rate is set when configuring communications on the communicating device.
If the communicating device is a PC, the data rate is set by RCP either when setting up RCP or
by changing settings while running RCP.
To set the data rate on the front comm. port, the five dip switch poles of switch S1 (see Figure
1-13) must be set according to Table 4-6. When the relay is viewed from the front, (front cover
removed) the switch S1 is located on the right side of the front panel near the top. (On the top
of the front panel and on the left for horizontally mounted relays.) Only the first three poles, #1,
#2 and #3, of the switch, are used to set the communications bit rate. Refer to Table 4-6 for the
correct position of the switch poles. Note that settings 110 and 111 result in the default bit rate
of 1200 bps.
4.7.2

OPERATIONS

When the communication hardware is in place, communicating with the front port requires
pressing the push-button beside the connector in order to switch from the rear port to front port.
There after, the communication will remain with the front until no data transfer has taken place
for fifteen minutes. After the fifteen times out, the active communications port returns to the rear
port. The push-button can be pressed again to enable an additional fifteen minutes of front port
communication activity.
RCP operations are identical for front and rear communication (RS-232C or INCOM). It is pos-
sible that the communication is unsuccessful the first time after a relay power-up or switching
between protection and recloser. In this case, a second attempt usually proves to be successful.
I.L. 40-386.4
4-9