Agilent Technologies 6843A Welding System User Manual


 
4 - Programming Examples
122
AC Voltage and Frequency
The ac rms output voltage is controlled with the VOLTage command. For example, to set the ac output
voltage to 125 volts rms, use:
VOLTage 125
NOTE: In the three-phase model, all phases are programmed to 125 volts rms because the
INSTrument:COUPle at *RST is set to ALL.
The ac source can be programmed to turn off its output if the ac output voltage exceeds a preset peak
voltage limit. This protection feature is implemented with the VOLTage:PROTection command as
explained in Chapter 3.
Maximum Voltage
The maximum rms output voltage that can be programmed can be queried with:
VOLTage? MAX
The maximum voltage that the ac source can output is limited by the peak value of the waveform. This is
425 V peak on all models. Since the user programs output voltage in units of rms volts, the maximum
value that can be programmed is dependent on the peak-to-rms ratio (crest factor) of the selected
waveform. For a sine waveform, the maximum ac voltage that can be programmed is 300 volts.
For Agilent models 6814B, 6834B and 6843A, you cannot program a voltage that produces a higher volt-
second on the output than a 300 Vrms sinewave.
NOTE: Because voltage commands are coupled with the waveform shape and voltage offset
commands, changing voltages without changing the waveform shape or voltage offset
may result in an error if the resulting peak voltage amplitude exceeds the maximum
voltage rating of the ac source. Refer to "Coupled Commands" for more information.
Voltage Ranges (Agilent 6814B/6834B/6843A only)
The Agilent 6814B, 6834B and 6843A have two voltage ranges that are controlled by a relay that switches
taps on an output transformer. The command that controls the range is:
VOLTage:RANGe MIN | MAX | 150 | 300
When the range is set to MIN (or 150), the maximum rms voltage that can be programmed for a sine
waveshape is 150 volts, but it is only on this range that the maximum output current rating is available. For
other waveshapes, the maximum programmable voltage may be different, depending on the waveform’s
voltage crest factor (peak-to-rms ratio).
NOTE: On the Agilent 6814B, 6834B and 6843A, the VOLTage:RANGe command is coupled with
the CURRent command. This means that the maximum current limit that can be
programmed at a given time depends on the voltage range setting in which the unit is
presently operating. Refer to "Coupled Commands" for more information.