58542 VXIbus Universal Power Meter
A-20 Publication 21555, Rev. E, September 2002
A.4.9 Reading Power Measurements Example 9
The following program uses BURSt Mode for the fastest measurement rates possible. The maximum
measurement speed is performed when TRIG:DEL is set to 0. TRIG:DEL controls the speed of sampling
and data buffering. When TRIG:DEL is set to 0.004, samples will be taken every 4 milliseconds, on both
channels if connected, and stored in internal data buffer. This speed does not control or account for the
meter’s internal data processing time after data acquisition or the speed of data transfer to the controller.
This second component of time, the time to get data from the 58542, is proportional to the number of
data points measured. Therefore, the example below uses only one channel and keeps the number of
points buffered to a minimum.
Both channels’ data will be taken at the same time during BURSt Mode. Power meter measurement
speed does not change when two sensors are connected versus only one sensor. However, the meter’s
processing time and the time to transmit the data over the VXI and GPIB interfaces takes longer due to
the additional sensor data. If two sensors are connected, calibrated, and their respective channels are set
to ON, then must read both arrays of data. Only read one array of data when one sensor is attached,
calibrated, and set to ON.
As shown in the examples, send the CALC#:MODE BURS command prior to sending the BURSt
Mode configuration commands TRIG:SOUR, TRIG:MODE, TRIG:COUN, and TRIG:DEL.
10 ALPHA ON
20 CLEAR SCREEN
30 !
40 OPTION BASE 1
50 DIM Id$[50],Err_msg$[70]
60 DIM Ques$[200],A$[80],Chan1sens_1(500)
70 DIM Chan2sens_2(500)
80 !
90 !
100 !###################################
110 ! Instrument ADDRESS ALLOCATION
120 !
130 ASSIGN @Slot0 TO 70100 ! 70100 is Logical Address of the Slot0 controller
140 ASSIGN @Pwr_mtr TO 70101 ! 70101 is Power Meter in 1st position right of slot 0
150 !###################################
160 !
170 ! Identify Attached Instruments
180 !
190 OUTPUT @Slot0;*Slot0;*IDN?
200 ENTER @Slot0;Id$
210 PRINT SLOT 0 is ;Id$
220 !
230 OUTPUT @Pwr_mtr;*IDN?
240 ENTER @Pwr_mtr;Id$
250 PRINT SLOT 1 is ;Id$
260 WAIT 1
270 !
280 !
290 CLEAR @Pwr_mtr
300 WAIT 1
310 OUTPUT @Pwr_mtr;*CLS ! Clears old messages from SYST:ERR buffer
320 WAIT 0.3
330 OUTPUT @Pwr_mtr;CALC1:MODE NORM! NORMal Mode to perform channel configuration
340 OUTPUT @Pwr_mtr;CALC1:POW 1 ! Channels 1 or 2 can be either POW 1 or POW 2
350 ! RAT and DIFF are illegal in SWIFt and BURSt Modes.
360 OUTPUT @Pwr_mtr;TRIG:SOUR IMM ! IMM set here to highlight conflict with BURSt operation.
370 !
380 !###################################
390 !
400 ! Entering BURSt Mode
410 !
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