Programming Example - HP 6811B User Manual

Programming Example

UPS Transfer Time Measurement
The following programming example illustrates how to use the ac source with the Dual Power Analyzer
(Option 020 or 022) to measure transfer time on a UPS. Transfer time is defined as the time it takes a
UPS to go from online-operation to battery-backup operation when the ac line fails.
This example starts with the ac source output voltage (UPS input voltage) at 120 Vac. The UPS output
voltage is connected to a load and to the Power Analyzer input. The ac source output turns on at 120 Vac,
then does a 50 ms dropout to 0 volts. Both the dropout and measurements are triggered at the same time.
The FETC:TVOLT:ABS? command is then used to return the transfer time, here defined as the time
between the start of the dropout and the time when the absolute value of the UPS output voltage exceeds
50 volts for at least 0.001 seconds.
100 ASSIGN @Ps TO 705
110 !
120 !
130 OUTPUT @Ps;"*RST"
140 OUTPUT @Ps;"VOLT 120" ! SET INITIAL INPUT VOLTAGE FOR UPS TO 120 VAC
150 OUTPUT @Ps;"OUTP ON"
160 WAIT 2
170 !
180 !
190 OUTPUT @Ps;"VOLT:MODE PULS" ! SET UP PULSE MODE FOR AC SOURCE OUTPUT
200 OUTPUT @Ps;"PULS:WIDT 0.05" ! SET PULSE WIDTH TO 50 MILLISECONDS
210 OUTPUT @Ps;"VOLT:TRIG 0"
220 !
230 !
240 OUTPUT @Ps;"TRIG:SYNC:SOUR PHAS" ! SETS DROPOUT SYNCHRONIZATION TO PHASE
250 OUTPUT @Ps;"TRIG:SYNC:PHAS 90"
260 OUTPUT @Ps;"TRIG:SOUR BUS"
270
280 !
290 !
300 OUTPUT @Ps;"OUTP:TTLT:SOUR BOT"
310
320 OUTPUT @Ps;"OUTP:TTLT:STAT ON"
330 OUTPUT @Ps;"TRIG:ACQ:SOUR TTLT"
340
350 !
360 !
370 OUTPUT @Ps;"INIT:IMM:SEQ1" ! ARMS THE PULSED DROPOUT TO WAIT FOR TRIGGER
380 OUTPUT @Ps;"INIT:IMM:SEQ3" ! ARMS MEASUREMENT PROCESS TO WAIT FOR TRIGGER
390 OUTPUT @Ps;"TRIG:IMM"
400
410 OUTPUT @Ps;"SENS:NSEL 2"
420 OUTPUT @Ps;"FETC:TVOLT:ABS? 50, 0, .001"
430 ENTER @Ps;A
440 PRINT A
450 END
16
! AC SOURCE IS AT ADDRESS 5, INTERFACE 700
! BEGIN FROM A KNOWN STARTING POINT WITH RESET
! TURNS AC SOURCE OUTPUT ON AT 120 VAC
! MAKE SURE UPS OUTPUT HAS TIME TO SETTLE
! SET PULSED (TRIGGERED) VALUE TO 0 VOLTS
! SETS DROPOUT START PHASE TO 90 DEGREES
! SETS DROPOUT TRIGGER AND MEASUREMENT
! TRIGGER SOURCE TO BUS TRIGGER
! SETS SIGNAL TRIGGER SOURCE TO BEGINNING
! OF TRANSIENT (BOT)
! ENABLES TRIGGER OUTPUT SIGNAL
! SETS MEASUREMENT TRIGGER SOURCE TO
! TRIGGER OUTPUT SIGNAL
! TRIGGERS PULSED VOLTAGE DROPOUT TO 0 VOLTS
! AND STARTS THE MEASUREMENT PROCESS
! SELECTS POWER ANALYZER INPUT FOR MEASUREMENTS
! RETURNS THE TRANSFER TIME MEASUREMENT
! PRINTS THE TRANSFER TIME MEASUREMENT
! FETCHES TRANSFER TIME