Local Operation
3-30 M370046-01
Using the External Shutdown Function
Use the external shutdown function to enable or disable the output of the
power supply via a logic level signal. When the external shutdown is
triggered, the power supply will display SD POL on the output voltage and
current displays and the ALARM LED will illuminate. The external
shutdown is useful for making adjustments to either the load or the power
supply without shutting off the power supply or for using the power
supply as part of a larger test system in which digital or analog control is
required.

Activating the External Shutdown Function

To activate the external shutdown function, use the AUX output supply
provided on the Analog Programming Connector J3. This input has a user
selectable polarity with logic low input from 0.0V to 1.2V and logic high
from 2.0V to 15V. The control signal for this input must be capable of
sinking 10mA minimum. This input is also compatible with the use of dry
contacts, where a short is logic low and an open is logic high. The input
lines of the shutdown circuit are fully optically isolated. See page C–4 for
specifications.
Once the External Shutdown has been triggered, the display will blink the
SD POL and the ALARM LED will be illuminated.

Controlling the External Shutdown Function

The external shutdown circuit accepts a voltage or dry contact control
(high or low logic level) to enable or disable the power supply output.
Make connections for the signals at the AUX Output and Isolated Analog
Programming Connector on the rear panel. (See “AUX Output and
Isolated Analog Programming (ISOL) Connector” on page 4–20 for more
information.)
To activate the shutdown function:
Connect the control signal source to the Shutdown pin (J3.12) on the Aux
Output and Isolated Analog Programming Connector with the control
circuit ground connected to Isolated Ground pin (J3.6).
The External Shutdown pin is pulled high internally (normally high).
Therefore, if this feature is not used, the polarity should be set to 1 to
avoid false triggering. (See “Defining the Polarity of the External
Shutdown Signal” on page 3–31 for instructions.)