5.6
SEL-400 Series Relays Instruction Manual Date Code 20171006
Control
Disconnect Logic
Disconnect Switch Status and Alarm Logic Inputs
89AM
m
, 89BM
m
The 89AMm and 89BMm SELOGIC control equations represent the normally
open and normally closed disconnect switch auxiliary contacts. Typically, these
are set to relay inputs that are wired to the auxiliary contacts.
89CIM
m
, 89OIM
m
Input 89CIMm asserts for expiration of the close immobility timer, while input
89OIMm asserts for expiration of the open immobility timer. Timer expiration
indicates one of two conditions. The first is that an open-to-close operation of the
disconnect switch failed to move the switch enough to open the normally closed
auxiliary contact 89BMm. The second is that a close-to-open operation of the dis-
connect switch failed to move the switch sufficiently to open the normally open
auxiliary contact 89AMm.
Disconnect Switch Status and Alarm Logic Settings
89ALP
m
This setting in the Bay settings class defines the disconnect switch alarm time.
Disconnect Switch Status and Alarm Logic Outputs
89AL
m
If a disconnect switch operation initiated from the front panel does not complete,
the 89ALPm timer expires and the 89ALm Relay Word bit asserts. Expiration of
the 89ALPm timer indicates that an initiated disconnect operation failed to com-
plete and the disconnect switch is in an undetermined state. In addition, the
89CSTm or 89OSTm timer also expires to deassert the output signal (89CLSm or
89OPEm), thus ensuring that there is not a constant signal applied to the disconnect.
Figure 5.3 Disconnect Switch Status and Alarm Logic
Relay
Word
Bits
89ALPm
0
89CIMm
89OIMm
89ALm
89AMm
89BMm
Disconnect
Alarm Timer
Xnor Logic
Table
Input
AB
Output
00
01
10
11
1
0
0
1
89OIPm
89CLBm
89CLm
89OPNm
SEL
OGIC
Control Equation
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