Tham khảo tài liệu 'oscilloscopes episode 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 28 Oscilloscopes things settings of channels not currently in use. Additionally when the instrument is under remote control either RS232 fitted as standard or IEEE optional the STATUS LOCAL button functions as a go to LOCAL command returning control to the front panel. Two lines of user-definable text can be displayed on the screen see Figure . This can provide useful additional information on a screen shot when photographing the displayed traces. This facility is accessed via a submenu called up after pressing the UTILITY button situated at the top of the screen above the CURSOR button. Photographing the screen can conveniently be carried out using the PM 9381 001 oscilloscope camera illustrated in Chapter 4. Other facilities So many facilities are provided by the microcontroller and software which monitor and control all aspects of the instrument s operation that they cannot be covered in full here so a representative selection is presented. The CAL function can be called up by pressing the CAL button situated to the right of the AUTO SET button. This function makes fine adjustments to input trigger and timebase circuitry to achieve high accuracy even under extreme ambient conditions. Under normal laboratory conditions weekly or even monthly calibration is adequate. Note that the instrument should be allowed to warm up thoroughly before calibration and that the CAL button must be pressed for at least 2 seconds to initiate this function. A more complete calibration procedure advised annually or every 2000 hours use can be called up by a special submenu under the MAINTENANCE menu. One of the most important functions is AUTO SET which can be executed by pressing the AUTO SET button located directly above the STATUS LOCAL button. This switches off any input channels at which it detects no signal and for the others selects a suitable Y sensitivity setting with . coupling - AUTO SET does not work for very low signal frequencies. Additionally input .
