Date Code 20000421 Installation 6-3
SEL-251, -2, -3 Instruction Manual
Output Contact Jumper
TRIP (terminals 1,2) JMP11
TRIP (terminals 3,4) JMP10
CLOSE JMP9
A1 JMP8
A2 JMP7
A3 JMP6
A4 JMP5
ALARM JMP4
Communication Port External Power Jumpers
DC power is available from Port 1 and Port 2R to power external devices. Jumpers must be
selected to route dc power to the rear panel connectors. The internal jumpers are near Port 1 and
are labeled as follows: JMP12 = +5 V; JMP13 = +12 V; JMP14 = -12 V. Use caution to ensure
the dc current requirement of the external equipment does not exceed the relay power supply
specifications. Only route dc power to the rear ports if required for your application.
Jumper Installation Instructions
The power available from these ports is limited and should be used only for SEL-RDs,
SEL-DTAs, dc-powered modems, or other low-wattage devices approved by SEL.
The power is available on either Port 1 or Port 2R. Port 2F, located on the front of the relay,
does NOT have power available.
To install jumpers for supplying power through the rear EIA-232 ports perform the following
steps:
1. Remove the relay top cover or withdraw the main circuit board.
2. Locate jumpers JMP12 (+5 Vdc), JMP13 (+12 Vdc) and JMP14 (-12 Vdc) near the
AUX INPUT connector.
3. Remove and install the needed jumpers in the "on" position.
4. Replace the top cover or reinsert the main circuit board. (Ensure that the board is
correctly seated and the cables to the power supply and input transformers are
reconnected.)
EIA-232 and IRIG-B Installation
The following information contains specific details regarding communications port pinouts.
A pin definition of the 9-pin port connectors and cabling information for the EIA-232 ports
appears in Figure 6.1. The following cable listings show several types of EIA-232 cables. These
and other cables are available from SEL. Cable configuration sheets are also available at no
charge for a large number of devices. Contact the factory for more information.
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