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2.25.1 Drop-off and pick-up characteristic
Figure 2.25-1 shows the UVS characteristic as hatched area with concentric circles. The pick-
up threshold voltage (PU) is represented the outer circle; the drop-off voltage point (DO) is
represented the dotted circle. The PU voltage of the UVS1 element is set using [UVS1]. The
DO voltage of the UVS1 element is set using [UVS1-DPR].
The inner circle shows the area in which the UVS function is blocked when the value of
the block voltage is set for [UVSBLK]. Setting [TUVSBLK] is also provided so that the user can
delay blocking the UVS1 and UVS2 elements using the setting.
Figure 2.25-1 UVS1 element characteristic
2.25.2 Time characteristic
The UVS element has the relationship between an input voltage and an operation time; the
relationship is divided into two time characteristics: (i) the definite time (DT) and (ii) the
inverse definite minimum time (IDMT).
(i) Definite time characteristic (DT)
Setting pick-up operation
The user is required to set DT for scheme switch [UVS1-Timer] when the UVS1 element should
run in the DT characteristic. The UVS1 element has a delay timer for the operation; the user
can set a delay time using setting [TUVS1]. The user can find the delay timer in the UVS
function logic. (See section 2.25.4)
Setting drop-off operation
Resetting the UVS1 element is performed instantly when a voltage exceeds over the drop-off
voltage.
(ii) Inverse definite minimum time (IDMT) characteristic
To operate the inverse definite minimum time (IDMT), set scheme switch [UVS1-Timer] IDMT.