Advanced Power Designs VXI600 Programmable Power Supplies QUESTION -------- I want to send SCPI commands to the second power supply in the VXI600, but all my commands are issued to the first supply? ANSWER ------ The VXI600 can have up to three seperate power supplies within the unit. To individually access each one, you must tell the VXI600 unit which supply is the "ACTIVE" supply. All power supply specific commands (such as a :SOUR:VOLT 5 to set the voltage to 5VDC) will apply to the ACTIVE supply. The SCPI command to set a power supply to be active are: Power Supply Stage 1 :INST:NSEL 101 Power Supply Stage 2 :INST:NSEL 102 Power Supply Stage 3 :INST:NSEL 103 QUESTION -------- My VXI600 is intermittently operating incorrectly. Sometimes it works, and other times, the voltages are not properly set, or the display values are wrong or invalid? ANSWER ------ While the unit may require return to the factory for service, check the backplane voltage. VXI backplanes have 5VDC and 12VDC requirements, as well as a solid grounding. VXI instruments connected to chassis with floating grounds or backplane voltage values which are off by even small margins, can exhibit symptoms like what is described. If the problem persists, contact APD Technical Support for additional help. QUESTION -------- The VXI600 does not "power up" when placed in the card cage? ANSWER ------ A few things to check are: * The VXI chassis backplane voltages are set according to the VXI specification. * There are no bent or broken back plane pins. * There may be a bad backplane slot. Test this by trying a different slot. * The VXI600 is not properly seated in the chassis. It may be necessary to screw the front bezzel down tightly. QUESTION -------- I am not sure of which commands, and in what order, are needed to perform the various VXI600 operations, such as setting voltage, trips, etc? ANSWER ------ The VXI600's Users Guide has an Appendix with several example dialogs. The Users Guide can be downloaded directly from the APD web site under the SUPPORT page. QUESTION -------- What software drivers are available for the VXI600? ANSWER ------ Software drivers exist for LabWindows DOS, LabWindows CVI, and LabView. These drivers are available from National Instruments, or can be downloaded from the APD web site, under the SUPPORT page.