HP 8153 A Operating And Programming Manual

Also see for HP 81551MM: Operating manual

2The Auto KeyAuto enables or disables automatic ranging for the result. Automatic rangingensures that the result has a displayed value between 9% and 100% of fullscale. While you have automatic ranging enabled, the operation-indicator showsAUTO in the middle of the display. The default state is for automatic ranging tobe enabled.The Up KeyThis key selects the next higher range. If automatic ranging was in operation,this key disables it.Example If the instrument is currently in the range 2.000 to 19.999W,pressing Up takes it to the 20.00 to 199.99W range.The Down KeyThis key selects the next lower range. If automatic ranging was in operation,this key disables it.Example If the instrument is currently in the -20dBm range, pressingDown takes it to the -30dBm range.The Analog OutputThe analog output is the BNC connector on the front of the sensor module. Itoutputs a voltage directly proportional to the strength of the optical signal atthe optical input, in the current range.The analog signal is always in the range 0 to 2V, 2V corresponding to a fullpower input signal in the current range, 0V corresponding to no input signal.If the range changes, for example, during autoranging, the level to which 2Vcorresponds changes. Therefore it is recommended, if you want to use theanalog output, disable autoranging and select the best range for the applicationwith Up or Down .Possible applications for the analog output, would be to close the feedbackloop controlling the current supplied to a laser; or to monitor optical power onan oscilloscope (the analog signal reacts instantaneously to the input signal,whereas the power shown on the display is subject to averaging).Local Control - Measure Mode 2-13All manuals and user guides at all-guides.com