Technical data

1MRS751108-MUM

Protection Relay

Technical Reference Manual, General

REX 521

5.1.16.1. Special features of alarm LEDs

It is also possible to activate alarm LEDs by writing to parameter Alarm LED

states from HMI, or by using serial communication. This works even if the

alarms are not enabled (enabling alarms, see “Alarm LEDs” on page 45). The value

written to that parameter is then logically combined together (by an OR function)

with alarms enabled as described in the previous section.

The actual state of the alarm LEDs can also be read from the parameter Alarm LED

states by using serial communication, or by reading the state from HMI

(Configuration\Display\Alarm LED states).

In the HMI, the state of the alarm LEDs is shown bit-wise starting from the right

with LED1. The LEDs that were activated by writing to parameter Alarm LED

states can be acknowledged by pressing the [C] button for 2 s in the main view.

Clearing a certain LED without affecting the other LEDs can be done by setting the

corresponding bit to 0 in parameter Alarm LED states. Writing to parameter

Alarm LED states from HMI is useful when testing if a certain LED lights up.

5.1.16.2. Writing signal names on alarm LED label

You can write or print the alarm LED signal names on a special label presented in

Fig. 5.1.16.2.-1. The transparencies for the label are delivered with the relay. The

label contains eight text rows, one for each alarm LED.

A051915

Fig. 5.1.16.2.-1 Alarm LED label

After an auxiliary supply break, the state of the alarm LEDs is

restored to the same state as before the break. This means that alarms

will be seen even if the alarm went off during the break and

regardless of the mode. The alarms can be acknowledged (cleared)

only from the main view by pressing the [C] button for 2 seconds

106

-0,5

ABB OY

Distribution Automation

1MSC 971082

Alarm LED label

Hälytys-LED kilpi

REX 521

971082