ABB RELION REX640 - Page 120

Alarm mode alternatives
The ALARM input behavior can be selected with the alarm mode settings from the
alternatives "Follow-S", "Follow-F", "Latched-S" and "LatchedAck-F-S". The OK input
behavior is always according to "Follow-S". The alarm input latched modes can be
cleared with the reset input in the application logic.
Figure 44: Symbols used in the sequence diagrams
"Follow-S": Follow Signal, ON
In this mode ALARM follows the input signal value, Non-latched.
Activating
signal
LED
Figure 45: Operating sequence "Follow-S"
"Follow-F": Follow Signal, Flashing
Similar to "Follow-S", but instead the LED is flashing when the input is active, Non-
latched.
"Latched-S": Latched, ON
This mode is a latched function. At the activation of the input signal, the alarm
shows a steady light. After acknowledgement by the local operator pressing any key
on the keypad, the alarm disappears.
Activating
signal
LED
Acknow.
Figure 46: Operating sequence "Latched-S"
"LatchedAck-F-S": Latched, Flashing-ON
This mode is a latched function. At the activation of the input signal, the alarm
starts flashing. After acknowledgement, the alarm disappears if the signal is not
present and gives a steady light if the signal is present.
Basic functions
1MRS759142 F
120 REX640
Technical Manual