Schweitzer Engineering Laboratories SEL-311C, Instruction Manual

Page: 185 / 748

5.29
Date Code 20060320
Instruction Manual SEL-311C Relay
Trip and Target Logic
Directional Comparison Blocking Logic
OUT105 = STOP and
OUT107 =
STOP
Depending on the installation, perhaps one output contact (e.g., OUT104 =
DSTRT + NSTRT) can be connected in parallel to both
START inputs on the
communications equipment in Figure 5.16 . Then output contact OUT106 can be
used for another function.
Depending on the installation, perhaps one output contact (e.g., OUT105 =
STOP) can be connected in parallel to both
STOP inputs on the
communications equipment in Figure 5.16 . Then output contact OUT107 can be
used for another function.
Figure 5.16 also shows communications equipment RX (receive) output
contacts from each remote terminal connected to separate inputs IN104 and
IN106 on the SEL-311C. The inputs operate as block trip receive inputs for the
two remote terminals and are used in the SEL
OGIC
control equation setting:
BT = IN104 + IN106
Depending on the installation, perhaps one input (e.g.,
IN104
) can be connected
in parallel to both communications equipment RX (receive) output contacts in
Figure 5.16 . Then setting BT would be programmed as:
BT = IN104
and input IN106 can be used for another function.
In Figure 5.15 and Figure 5.16 , the carrier scheme cutout switch contact
(85CO) should be closed when the communications equipment is taken out of
service so that the BT input of the relay remains asserted. An alternative to
asserting the BT input is to change to a settings group where the DCB logic is
not enabled.
Figure 5.15 SEL-311C Connections to Communications Equipment for a Two-Terminal Line DCB Scheme
(—)
OUT105 = DSTRT + NSTRT
OUT106 = STOP
(+)
OUT106
(TX) START STOP
OUT105
(TX) RX 85CO
SEL-311C
(partial)
IN104
to/from
remote
terminal
BT = IN104
RX
TX