To measure the RMS current, use: 
  MEAS:CURR? 
To measure the peak current, use: 
  MEAS:CURR:AMPL:RES  /* resets track and hold for peak curr. meas. 
    /* It may be need to turn the output on or program 
    /* as specific voltage at this time before taking a 
    /* peak current reading. 
  MEAS:CURR:AMPL:MAX?  /* retrieves peak current reading. 
To measure the current crest factor, use: 
  MEAS:CURR:CRES? 
Power Measurements 
To measure the true power, use: 
  MEAS:POW:REAL? 
To measure the apparent power, use: 
  MEAS:POW:APP? 
To measure the power factor, use: 
  MEAS:POW:PFAC?