2-18
Installation
Date Code 20020129
SEL-387E Instruction Manual
the +5 Vdc for Port 2 (see Table 7.1 in
Section 7: Serial Port Communications and
Commands
). If these jumpers are installed, be certain not to short the power supply with an
incorrect communication cable. The +5 Vdc connections supply current as high as 1 A.
Solder jumpers JMP3 and JMP4 allow connection of an IRIG-B source to Port 2. Removal of
JMP3 and JMP4 will cause Port 2 to no longer accept an IRIG-B signal. The Port 1 connector
always accepts an IRIG-B signal. Port 2 and Port 1 IRIG-B circuits are in parallel; therefore,
connect only one IRIG-B source at a time.
Condition of Acceptability for North American Product Safety Compliance
To meet product safety compliance for end-use applications in North America, use an external
fuse rated 3 A or less in-line with the +5 Vdc source on pin 1. SEL fiber-optic transceivers
include a fuse that meets this requirement.
Other Jumpers
Additional main board jumpers JMP5A through JMP5D, located near JMP6, are not functional
in the SEL-387E Relay. Originally they were installed for developmental testing purposes but
are not used in the production version of the relay. Jumpers must not be installed in any JMP5
position.
Low-Level Analog Interface
SEL designed the SEL-387E Relay main board to accept low-level analog signals as an optional
testing method.
Section 10: Testing and Troubleshooting
contains a more detailed discussion of
the patented Low-Level Test Interface; and Figure 10.1 shows the pin configuration. The
SEL-RTS (Relay Test System) interfaces with the relay through a ribbon cable connection on the
main board. With the front panel removed, the low-level interface connector is on the front edge
at the far right of the top board. Refer to Figure 2.13. Remove the ribbon cable from the main
board (top board), and connect the SEL-RTS ribbon cable to the main board. This removes the
connection from the transformers in the bottom of the relay chassis and connects the SEL-RTS
system for low-level testing. Refer to the SEL-RTS Instruction Manual for system operation.
For normal operation, be sure to properly reinstall the ribbon cable that connects the
transformers in the bottom of the chassis to the main board.
Clock Battery
Refer to Figure 2.13 for clock battery B1 location. This lithium battery powers the relay clock
(date and time) if the external power source is lost or removed. The battery is a 3 V lithium coin
cell. At room temperature (25
C) the battery will operate nominally for 10 years at rated load.
Because little self-discharge of the battery occurs when an external source powers the relay,
battery life can extend well beyond the nominal 10 years. The battery cannot be recharged.
If the relay does not maintain the date and time after power loss, replace the battery. Follow the
instructions previously described in
Accessing the Relay Circuit Boards
in this section to
remove the relay main board.
