Controlling Output Shutdown; Output Shutdown Connection - National Instruments RMX-4120 User Manual

Controlling Output Shutdown

This section explains how to use an external contact to turn output off. This functionality differs
from the Controlling the Output On and Off States
an output shutdown requires the unit to be power cycled.
Caution
the reinforced or double insulation of the external contact (S) and the connected cable
must be greater than or equal to the isolation voltage of the RMX programmable power
supply. Refer to Appendix A, Specifications, for the isolation voltage of your model.
If one of the output terminals is connected to chassis ground, the insulation of the
external contact and the connected cable must have a reinforced or double insulation
with a capacity greater than or equal to the maximum output voltage relative to the
chassis.
When using shielded cables for the connection, for uncovered sections of the shielded
cables, use insulation tubes to secure reinforced or double insulation with a capacity
greater than or equal to the isolation voltage of the RMX programmable power supply.
To reduce the noise on the output, connect a 2-core shielded wire or a twisted pair wire, and keep
the wire as short as possible. If the wiring is long, it becomes easy for noise to influence the
operation of the RMX programmable power supply. Even if you use wires that are designed to
suppress noise, the RMX programmable power supply may not operate properly.
If you use a shielded cable, connect the shield to the negative output terminal.
If you apply a LOW (0 to 0.5 V) or short-circuit pin 6 to pin 19 of the J1 connector, the output
shuts down.
To recover, set pin 6 of the J1 connector to HIGH (4.5 to 5 V) or open the pin, and then turn the
POWER switch off and then on.

Output Shutdown Connection

Connect your external contact between pins 6 and 19 of the J1 connector. The open-circuit
voltage across pins 6 and 19 is approximately 5 V. The short-circuit current across pins 6 and 19
is approximately 0.5 mA.
Use external contacts that have a contact rating greater than or equal to 0.5 mA at 5 VDC.
Risk of electric shock. If neither output terminal is tied to chassis ground,
RMX Programmable Power Supplies User Manual
external control pin, because recovering from
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