SurgeX SX-2120 - Manual (Page 7)

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SEQ/SEQ-1U User Manual
Software Version 2.0
3.2.2 Over-Ride Input
The SEQ has the option of adding an over-ride function for purposes such as providing fire safety over-
ride to force the system either on or off. An over-ride is initiated by applying a dc voltage of 5-30V or by a
sustained contact closure. The selection of dc voltage or contact closure is accomplished during
programming. This topic is covered fully in the programming section.
Connect the over-ride signal to the “over-ride” input and “common”. In the case of a dc voltage, connect
the positive wire to “over-ride” and the negative wire to “common”.
3.2.3 External LED Connections
The SEQ is able to drive external LEDs or other signaling devices through its 12V DC output which can
provide up to 40mA of current. External LEDs connected in this way will mimic the LED on the front
panel. When connecting LEDs to the 12V output, a series resistor is required. For example, many LEDs
work well with 10mA of current, so a 1K resistor is usually a good choice. If more than one LED is
required, then use a separate series resistor for each LED. In this example, four external LEDs could be
powered at 10mA each from one SEQ. If more than four LEDs are required, it will be necessary to
increase the series resistor so that the total load is not more than 40mA.
Connect each LED anode to “12V DC output” through a resistor, and the cathodes to “Common”.
Program the 12V DC Output for “LED”. This causes LEDs connected to the SEQ to flash while the unit is
powering up or powering down in the same manner as the front panel LED.
3.2.4 Confirmation Connection
The SEQ offers two ways to provide confirmation feedback to a central controller: a 12V DC output and
isolated relay contacts. Confirmation tells the controller that the SEQ has indeed powered up or that it is
fully powered down. If the 12V DC output and the Aux Relay contacts are not used for any other
function, you will be free to choose whichever provides the best interface for the application. However, if
one of these outputs is used for another function you will have to use the one that is available.
To use the 12V DC output for confirmation, connect “12V DC output” to the positive input of the
controller and “Common” to ground. The output will be at 12V when all banks are powered up and will be
zero when all banks are powered down. Program 12V DC Output for “Confirm”. Note that the SEQ
common terminal is shared between the inputs and the 12V DC output. If you need relay contacts for
confirmation and you are using the Aux Relay for another function you can connect a small relay
between the 12V DC output and common. The relay coil current must not be more than 40mA, and you
must connect a diode such as a 1N4148 or 1N4002 across the relay coil (cathode to +12V dc) to
suppress the back-EMF from the coil. If you need assistance with this please contact our technical
support department.
To use the Auxiliary Relay contacts for confirmation, connect the contacts to the input of the controller.
The relay contacts will be closed when all
banks are powered up and open when all
banks are powered down. The default for menu
item “Aux Output” is “Confirm” so you do not
need to program this item unless you
previously changed it. The contacts are rated
for 30V DC at 1 Amp.