CHAPTER 8: AUTOMATION AUTOMATION CONTROL
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 459
Step-Up Mode
Range: Time-out, Acknowledge
Default: Time-out
This setting defines the selector mode of operation. When set to “Time-out,” the selector
changes its position after a pre-defined period of inactivity at the control input. The
change is automatic and does not require any explicit confirmation of the intent to
change the selector's position. When set to “Acknowledge,” the selector changes its
position only after the intent is confirmed through a separate acknowledging signal. If
the acknowledging signal does not appear within a pre-defined period of time, the
selector does not accept the change and an alarm is established by setting the SELECTOR
STP ALARM output FlexLogic operand for three seconds.
To activate a selector switch via the front panel, have this setting select the
corresponding pushbutton operand (for example, PUSHBUTTON 1 ON). This operand is
asserted only if the corresponding pushbutton element has been enabled.
Acknowledge
Range: any automation logic operand or shared operand
Default: OFF
This setting selects an acknowledging input for the stepping up control input. The pre-
selected position is applied on the rising edge of the assigned operand. This setting is
active only under the acknowledge mode of operation. The acknowledging signal must
appear within the time defined by the
Timeout setting after the last activity of the
control input. A user-programmable pushbutton typically is configured as the
acknowledging input.
3-Bit A0, 3-Bit A1, 3-Bit A2
Range: any automation logic operand or shared operand
Default: OFF
These settings specify a three-bit control input of the selector. The three-bit control word
pre-selects the position using the following encoding convention.
Table 28: Selector switch three-bit control word
The rest position (0, 0, 0) does not generate an action and is intended for situations when
the device generating the three-bit control word is having a problem. When in time-out
mode, the pre-selected position is applied in the time specified (in seconds) by the
Timeout setting after the last activity of the three-bit input. When in acknowledge mode,
the pre-selected position is applied on the rising edge of the acknowledging input
specified by the
3-Bit Acknowledge setting.
The stepping up control input (selected by the
Step-Up setting) and the three-bit control
inputs (A0, A1, and A2) lock-out mutually. Once the stepping up sequence is initiated, the
three-bit control input is inactive. Once the three-bit control sequence is initiated, the
stepping up input is inactive.
A2 A1 A0 Position
000rest
0011
0102
0113
1004
1015
1106
1117
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