Hameg HM 2005 Manual 

Hameg HM 2005 Manual  Manual pdf 32 page image

Subject to change without notice32any external connections). Using the test prods, identical testpoints in each circuit can be checked, and a defect can bedetermined quickly and easily.Possibly the device itself under test contains a reference circuit(e.g. a second stereo channel, push-pull amplifier, symmetricalbridge circuit), which is not defective.AdjustmentsAs described in the“Menu” section, the instrument`s softwarecontains the menu“TEST & CALIBRATE”. Calling this menucauses the submenus “TEST” and “CALIBRATE” to bedisplayed.“RO POSITION” is displayed after “TEST” was called. Aftercalling “RO POSITION” four rectangles are displayed. Therectangles position and size should coincide with the CRTgraticule lines. In spite of the CRT mumetal shielding, deviationsof up to 1mm are unavoidable due to the influence of the earthmagnetic field.The following items can be used by operators not equipped withprecision instruments. After the required warm-up time of 20minutes, first the instrument must be switched off and on againwith the AUTOSET button pressed constantly until the main menubecomes visible. In the“CALIBRATE” submenu the followingitems can be chosen: Y AMPLIFIER and TRIGGER &HORIZONTAL.Each item is called by pressing the SAVE / SET pushbutton. Thenthe instrument automatically adjusts and stores the adjustmentvalues. In case of the Y amplifiers these are the field effecttransistor‘s operating points, the invert and the variable gainbalance. For the trigger amplifier it is regarding the DC operatingpoints and the trigger threshold.RS232 InterfaceSafetyCaution:All terminals of the RS232 interface are galvanicallyconnected with the oscilloscope and subsequently withprotective (safety) earth potential.Measurement on a high level reference potential is not permittedand endangers operator, oscilloscope, interface and peripheraldevices. In case of disregard of the safety warnings contained inthis manual, HAMEG refuses any liability regarding personal injuryand/or damage of equipment.OperationThe oscilloscope is supplied with a serial interface for controlpurposes. The interface connector (9 pole D- SUB female) islocated on the rear of the instrument. Via this bi-directional port,the instrument parameter settings can be transmitted to, orreceived from a PC.The maximum connecting cable length must be less then 3meters and must contain 9 screened lines connected 1:1. Thepin connection of the oscilloscope RS232 interface (9 pole D-SUB female) is determined as follows:Pin2 Tx data (data from oscilloscope to external device)3 Rx data (data from external device to oscilloscope)7 CTS (clear to send)8 RTS (request to send)5 Ground (reference potential - connected via theoscilloscope’s power cord with protective earth)9 +5V supply voltage for external devices (max. 400mA)The maximum voltage swing at pin 2, 3, 7 and 8 is ±12 volt.The RS232 parameter are: N-8-2 (no parity bit, 8 data bits, 2stop bits, RTS/CTS hardware protocol).Baud-Rate SettingAfter the first POWER UP (switching on of the oscilloscope ) andthe first command SPACE CR (20hex, 0Dhex) sent from the PC,the baud rate is recognized and set automatically between 110baud and 115200 baud. The oscilloscope is then switched over toREMOTE control mode. The oscilloscope then transmits theRETURNCODE: 0 CR LF to the PC. In this status all settings(with the exception of those functions mentioned under “Controlsand Readout”) can be controlled via the interface only.Adjustments