© National Instruments | 3-11RMX Programmable Power Supplies User ManualCautions When Controlling the Output with an ExternalVoltage (Vext)You must take careful precautions when connecting external equipment to the J1 connector tomake sure you do not unknowingly short both output terminals to ground.Connect the cables so that output is not shorted. See the following figures for examples ofshorted output.Caution The Vext cable must not be referenced/connected to the chassis groundterminal. The signal must be floating relative to ground. Connecting/referencing thissignal to ground may cause the cable to be damaged. Refer to Figures 3-10 and 3-11for more information.If you are connecting the shield to the Vext side, do not connect the shield to theoutput terminal of the RMX programmable power supply.Figure 3-10. Connection Where the Output is Shorted by the Grounding of VextFigure 3-11. Connection Where the Output is Shorted by the Shield++–+––2-core shielded wireVext RMXOutput is shortedby the grounding of Vext,causing current to flow.Ground thepositive output terminal.Approximately the sameelectric potential asthe negative output terminalProhibited×J1++–+––2-core shielded wireVext RMXOutput is shortedby the shield,causing current to flow.Ground thepositive output terminal.Prohibited ×J1Approximately the sameelectric potential asthe negative output terminal
