ABB REG670 - Page 596

a
b
b>a
Selected current
StartCurr_UC1
Operation_UC1=On
Bin input: BLKUC1
STUC1
en05000750.vsd
TRUC1
Bin input: BLKUC1TR
DEF
AND
AND
IEC05000750 V1 EN
Figure 281: Simplified internal logic diagram for built-in first undercurrent step that is, UC1 (step UC2 has the
same internal logic)
a
b
a>b
Selected voltage
StartVolt_OV1
Operation_OV1=On
BLKOV1
Inverse time
selected
en05000751.vsd
Inverse
DEF
DEF time
selected
STOV1
TROV1
AND
BLKTROV1
AND
OR
IEC05000751 V1 EN
Figure 282: Simplified internal logic diagram for built-in first overvoltage step OV1 (step OV2 has the same
internal logic)
Section 11 1MRK502052-UEN B
Multipurpose protection
590
Technical manual